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ELIMINATION AND DETECTION OF DEBRIS USING MACHINE VISION, ADDITIONAL DE-STEMMER AND DE-TRASHER ON A CITRUS CANOPY SHAKE
AND CATCH MECHANICAL HARVESTER
By
ROHAN PATIL
A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE
UNIVERSITY OF FLORIDA
2010
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© 2010 Rohan Patil
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To my god, parents, friends and well-wishers
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ACKNOWLEDGMENTS
The journey of my master’s has been a wonderful experience, in which many
people have offered invaluable assistance. I want to express my deepest gratitude to
Dr. Won Suk Lee for his enormous support and guidance. He is the best advisor I have
ever had in my life. He always provided me greatest guidance in my life and study with
immense kindness and patience. He opened my eyes by introducing me to the precision
agriculture and machine vision. I also thank my committee members Dr. Reza Ehsani
and Dr. Fritz Roka for their kindness and guidance. All that I have learnt during the
course of my thesis would not have been possible without their dedications. I also thank
Dr. Schueller for sharing his valuable experience in the field of dynamics.
I especially thank Mr. Michael Zingaro, Mr. Orlando Lanni, and Mr. Steve Feagle
for sharing me their hands throughout my research. Mrs. Ramya Shankar shared her
programming experience with me. I would like to thank my friends Mr. Arun Kumar,
Rajneesh Bansal and Arvind Kumar for their encouragements and support.
Most importantly I would like to express my dearest appreciation to my family and
friends for their support and love.
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TABLE OF CONTENTS page
ACKNOWLEDGMENTS ...................................................................................................... 4
LIST OF TABLES ................................................................................................................ 7
LIST OF FIGURES .............................................................................................................. 8
LIST OF ABBREVIATIONS .............................................................................................. 11
ABSTRACT........................................................................................................................ 12
CHAPTER
1 INTRODUCTION ........................................................................................................ 14
Agricultural background of Florida State .................................................................... 14 What is Debris?........................................................................................................... 15 Citrus Greening and Citrus Canker ............................................................................ 16 Debris Generated by Mechanical Citrus Harvester ................................................... 17 Labor Productivity ....................................................................................................... 18 Needs for Debri Elimination System .......................................................................... 18 Objectives ................................................................................................................... 20
2 LITERATURE REVIEW .............................................................................................. 22
Different Types of Mechanical Harvester for Different Crops ................................... 22 Cucumber Mechanical Harvester ........................................................................ 22 Pepper Harvester ................................................................................................. 22 Chili Pepper Harvester ......................................................................................... 23 Tomato Mechanical Harvester............................................................................. 24 Corn Head Used to Minimize Debris ................................................................... 25 Greens Cutting Head ........................................................................................... 26
Citrus Mechanical Harvesting Systems ..................................................................... 26 Tractor Drawn Canopy Shake ............................................................................. 27 Trunk Shake and Catch Harvest Systems .......................................................... 28 Continuous Canopy Shake and Catch Harvest Systems ................................... 29 Abscission Agent.................................................................................................. 30 Reducing Debris in Trailer Loads by Using Abscission Agent ........................... 31
3 IMAGE PROCESSING ............................................................................................... 33
Why Image Processing?............................................................................................. 33 Hardware for Machine Vision .............................................................................. 33 Software ............................................................................................................... 34 Image Processing ................................................................................................ 34
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Image Processing Results ................................................................................... 36
4 MATERIALS AND METHODS ................................................................................... 39
Hardware for Regular and Extended De-stemmer .................................................... 39 Catch Frame De-trasher Modification ................................................................. 40 Testing Extended De-stemmer and De-trasher at Commercial Citrus Grove ... 41
Experiments ................................................................................................................ 47 Lab Experiment to Compare the Efficiency of Regular and Extended De-
stemmer ............................................................................................................ 47 Catch Frame De-trasher Modification Experiment.............................................. 48 De-trasher Modification Experiment at Commercial Citrus Grove ..................... 49
5 RESULTS AND DISCUSSION ................................................................................... 52
Comparison between De-stemmers .................................................................... 52 Catch Frame De-trasher Results ......................................................................... 55 Modified Extended De-stemmer and De-trasher Results at Citrus Grove ......... 58 Discussion ............................................................................................................ 63 New Ideas for Future Modification ....................................................................... 65
6 CONCLUSION ............................................................................................................ 69
APPENDIX: ACTUAL MASS OF DEBRIS FOR REGULAR AND EXTENDED DE-STEMMER .................................................................................................................. 72
LIST OF REFERENCES ................................................................................................... 76
BIOGRAPHICAL SKETCH................................................................................................ 78
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LIST OF TABLES
Table page 3-1 Calibration of fruit samples .................................................................................... 36
3-2 Calibration of debri samples .................................................................................. 37
3-3 Predicted mass and pixel area for regression analysis ........................................ 37
4-1 Mass of fruits and debris for regular and extended de-stemmer .......................... 50
5-1 Results obtained from t-test. .................................................................................. 52
5-2 Percentage of debris eliminated by regular and extended de-stemmer. ............. 53
5-3 Percentage of debris removed by regular and extended de-stemmer. ................ 54
5-5 Stem removal analysis for length less than 0.05 meter and greater than 0.05 meter. ...................................................................................................................... 56
5-6 Debris elimination analysis for catch frame de-trasher. ........................................ 57
5-7 Total amount of debris received from regular and extended de-stemmer truck load. ........................................................................................................................ 59
5-8 Mass of debris removed by debri removal conveyor belt for regular and extended de-stemmer truck load ........................................................................... 61
5-9 Mass of debris removed by de-trasher for regular and extended de-stemmer truck load ................................................................................................................ 62
5-10 Overall efficiency of the de-trasher ........................................................................ 63
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LIST OF FIGURES
Figure page 1-1 Leaves, Twigs along with citrus fruits collected on the catch frame of the
mechanical harvester. ............................................................................................ 15
2-1 Pik Rite 3100 cucumber mechanical harvester. .................................................... 22
2-2 Pik Rite pepper mechanical harvester.. ................................................................. 23
2-3 Pik Rite chili pepper mechanical harvester.. ......................................................... 24
2-4 Pik Rite tomato mechanical harvester.. ................................................................. 24
2-5 The 50 series cornhead used to eliminate debris.. ............................................... 25
2-6 The greens cutting head on the GH80.. ................................................................ 26
2-7 Tractor drawn canopy shake, tines penetrating the canopy.. ............................... 28
2-8 Trunk shake and catch harvester.. ........................................................................ 29
2-9 OXBO - Continuous canopy shake and catch harvester.. .................................... 30
3-1 Image acquisition systems. A) Firewire cameras. B) Halogen lamps. ................. 34
3-2 Images captured for image processing. A) Original image of debris. B) Corresponding binary image. ................................................................................. 35
3-3 Predicted actual mass vs. pixel area. .................................................................... 38
4-1 De-stemmers used for the experiment. A) Regular de-stemmer with the roller lengths of 0.61 m. B) Extended de-stemmers with the roller lengths of 0.91 m. ............................................................................................................................ 39
4-2 Hardware components used for conducting the experiment. ............................... 40
4-3 Catch frame modification. A) Typical catch frame on a mechanical harvester. B) The catch frame on a mechanical harvester with fruit and debris. C) The front view of the modified catch frame. D) Side view of the modified section of a catch frame. ......................................................................................................... 41
4-4 Field experiment setup. A) Disassembling the regular de-stemmer. B) Installation of extended de-stemmer on the mechanical harvester. ..................... 42
4-5 De-stemmer used for the experiment. A) Regular used de-stemmer B) Extended new de-stemmer. ................................................................................... 42
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4-6 Working of extended de-stemmer on the mechanical harvester and citrus fruits collected in a goat truck. ............................................................................... 43
4-7 Experimental setup at the citrus grove, goat truck unloading harvested citrus fruits into the hopper. ............................................................................................. 44
4-8 Weighing of fruit and debri samples. A) Load cell to measure the mass of fruits and debris in the hopper. B) Mass displayed on the digital screen. ............ 44
4-9 Debri removal conveyor belt installed at the end of the feeding conveyor belt inclined at an angle to remove big twigs. .............................................................. 45
4-10 Newly designed de-trasher installed on the pickup machine to test the debri removal efficiency................................................................................................... 46
4-11 Weighing platform to measure the mass of debris removed by the conveyor belt and de-trasher. ................................................................................................ 46
4-12 Fruit and debri samples used for experiment. A) Mixed sample of fruit and debris. B) Only debri samples. ............................................................................... 48
4-13 Fruit samples with different lengths of petioles. .................................................... 49
4-14 Measuring the mass of the goat truck with load and with no-load. A) Measuring front axle. B) Measuring rare axle. ...................................................... 50
4-15 Experimental setup. A) Fruit and debris unloaded in the hopper. B) Fruit and debris passing on the conveyor belt after the release of hydraulic operated gate of the hopper. C) Fruit and debris passing through the de-trasher. D) Clean load of fruits on the end conveyor belt loading the goat truck. .................. 51
5-1 Comparison between amount of debris removed. A) Regular de-stemmer. B) Extended de-stemmer. ........................................................................................... 52
5-2 Comparison of debri removal efficiency for fruit and debris with cycles 1-3 is one basket of fruit and debris that were fed on the conveyor belt three times, cycles 4-6 is two baskets of fruit and debris that were fed on the conveyor belt three times, cycles 7-9 is three baskets of fruit and debris that were fed on the conveyor belt three times and cycles 10-12 is four baskets of fruit and debris that were fed on the conveyor belt three times. ......................................... 54
5-3 Comparison of debri removal efficiency with only debri samples. ........................ 55
5-4 Fruit samples used for experiment. A) Before being fed on the modified catch frame. B) After being fed on the modified catch frame. ........................................ 56
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5-5 Stem removal efficiency with observations 1-2 were for fruit samples with petioles less than 0.05 meters and 3-12 were for fruit samples with petioles greater than 0.05 meters. ....................................................................................... 57
5-6 Catch frame modification experiment. A) Debris separated. B) Fruits and debris samples separated during the experiment. ................................................ 58
5-7 Debris collected below the feeding conveyor belt over a period of time. ............. 60
5-8 Big twigs and debris eliminated by the debri removal conveyor belt.................... 60
5-9 Debris eliminated by the de-trasher....................................................................... 62
5-10 Debris caught in-between adjacent spinners. ....................................................... 64
5-11 Petiole less than 0.05 meters which was difficult to extract.................................. 64
5-12 Two roller brushes installed on the conveyor belt rotating in the opposite direction for eliminating debris. .............................................................................. 65
5-13 Conveyor belt installed on mechanical harvester. ................................................ 66
5-14 Conveyor belt with no solid metal base. ................................................................ 67
5-15 Conveyor belt with three sets of brushes rotating in the opposite direction of the conveyor belt. ................................................................................................... 67
5-16 De-stemmer installed on the conveyor belt which is below the catch frame. ...... 68
5-17 De-stemmer installed on the catch frame for removal of debris. .......................... 68
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LIST OF ABBREVIATIONS
μ₁ amount of debris removed by the regular de-stemmer
μ₂ amount of debris removed by the extended de-stemmer
Hο null hypothesis
Hα alternative hypothesis
α significance level
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Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science
ELIMINATION AND DETECTION OF DEBRIS USING MACHINE VISION,
ADDITIONAL DE-STEMMER AND DE-TRASHER ON A CITRUS CANOPY SHAKE AND CATCH MECHANICAL HARVESTER
By
Rohan Patil
August 2010
Chair: Won Suk “Daniel” Lee Major: Agricultural and Biological Engineering
Detection of debris using machine vision at the citrus grove can be beneficial in
cost reduction for the processing plant and also lead to environmental safety.
Regression analysis was performed to find the indirect mass estimation of the debris by
using machine vision. The R2 value for debri mass estimation from the experimental
images was 0.84 between the predicted actual mass with pixel area in the images. This
system can be implemented to quantify the amount of debris.
The main objective of this research was to design an efficient debri elimination
system and to compare the efficiency of newly designed de-stemmer with regular de-
stemmer. A regular de-stemmer with a set of ten 0.61 meters long rollers and an
extended de-stemmer with a set of ten 0.91 meters long rollers were used as the first
design. Twelve baskets with different mass of fruit and debris samples were prepared
and used for debri removal experiment. A t-test was conducted to compare the amount
of debris removed by regular and extended de-stemmers. The debris removed by the
extended de-stemmer was more compared to regular de-stemmer. The efficiency of de-
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stemmer for petiole removal was 50% for petioles less than 0.5 meters and 86% for
petioles longer than 0.05 meters for second design.
A de-trasher, which was composed of eight rows of seven 0.3 meter long rollers in
each row, was designed and the efficiency of the de-trasher was 99.86% of the total
debris and fruit samples input. This system could be implemented on the harvester to
increase the efficiency of trash removal.
A newly designed de-trasher was tested to compare the efficiency of regular and
extended de-stemmer. One full load of harvested fruit and debris from a goat truck was
tested for each of the regular and extended de-stemmers. It was observed that 0.21% of
debris from the total mass of fruit and debris was received from the first load of regular
de-stemmer compared to 0.18% of debris from the total mass of fruit and debris was
received from the first load of extended de-stemmer. For the second load, it was
observed that 0.30% of debris from the total mass of fruit and debris was received from
the regular de-stemmer load compared to 0.16% of debris from the total mass of fruit
and debris from the extended de-stemmer. It was observed that 32.23% of debris from
the total mass of the debris from the overall load of fruit and debris of citrus fruits was
eliminated by the debri removal conveyor belt. The overall efficiency of the de-trasher
from the regular de-stemmer load was nearly 69.84% of the total debris was eliminated
whereas for extended de-stemmer load 67.58% of the total debris was removed
efficiently by the de-trasher. Therefore, the extended de-stemmer will be more efficient
in removing debris than the regular de-stemmer.
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CHAPTER 1 INTRODUCTION
The thesis addresses detection of debris using machine vision and elimination of
debris using additional de-stemmer and de-trasher on a citrus canopy shake and catch
mechanical harvester.
Agricultural background of Florida State
Florida State is in southeast part of United States of America. The climate in
Florida is humid and it receives an average rainfall of 1.27 meter per year. Most crops in
Florida are irrigated because of typical sandy soils and non-uniform rainfall distributions
often result in soil moisture below levels required for optimum production. Also, many
high-value specialty crops are grown in Florida, and large economic returns can be
obtained by using irrigation to maintain optimum soil moisture levels. Finally, irrigation
systems are extensively used for environmental modification, including frost or freeze
protection and crop cooling. These practices are required for economical production of
many Florida crops. Florida’s 40,000 commercial farms, utilizing 10 million acres,
continue to produce a wide variety of safe and dependable food products.
Florida is ranked first in the value of production of oranges, grapefruit, tangerines,
and sugarcane for sugar and seed along with the production of snap beans, fresh
market tomatoes, and cucumbers for fresh market, squash, bell peppers, and sweet
corn. Florida is also ranked second in production of greenhouse and nursery products,
strawberries and fourth in production of honey. According to the USDA National
Agricultural Statistics Service (2008), the total value of production in Florida is 73
percent of the total U.S. value for oranges ($1.5 billion), 65 percent of the total U.S.
value for grapefruit ($184.6 million), 55 percent of the total U.S. value snap beans ($217
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million), 53 percent of the total U.S. value for tangerines ($75.0 million), 50 percent of
the total U.S. value for sugarcane for sugar and seed ($446 million), 36 percent of the
total U.S. value for fresh market tomatoes ($464 million), 39 percent of the total U.S.
value for bell peppers ($183 million), 31 percent of the total U.S. value for cucumbers
for fresh market ($72 million) and 32 percent of the total U.S. value for watermelons
($152 million).
What is Debris?
Debris is also known as ‘trash’. Leaves, twigs, stems, dead animals, plastic
materials are forms of debris that can be mixed with loads of citrus fruits while
harvesting.
Figure 1-1. Leaves, Twigs along with citrus fruits collected on the catch frame of the mechanical harvester.
Harvesting of this debris at the processing plant has become a major concern
because this debris can cause major downtime of equipments, increase labor cost and
also increase the cost of juice production. The debri is generated by vigorous shaking of
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trees caused by the mechanical harvester. The debri can enter the processing plants in
the form of plastic bottles, dead animals, big sticks and diseased fruits.
Citrus Greening and Citrus Canker
Mossler and Aerts (2006) reported the statistical data about the production facts
and regions of oranges in Florida and situation of citrus greening and citrus canker.
Citrus greening, which is also commonly known as Huanglongbing (HLB), was first
found in the south Florida region of Homestead and Florida City in 2005. The HLB
species found in Florida was the Asian species which occurs in warm low altitude areas.
HLB disease is difficult to manage and continued production of citrus has proven difficult
and expensive in areas where it is widespread. Brlansky et al. (2009) reported an
overview on HLB disease such as diagnosis of HLB, difficulty in its management and
continued production of citrus. HLB management is expensive in areas where it is
widespread and some integrated pest management strategies are being used for the
removal of infected trees. Yates et al. (2008) reported the scouting methods such as
walking through groves or riding on all-terrain vehicles (ATVs) or on elevated platforms
for detection of disease, marking suspect trees with flagging tape are some methods
suitable to avoid spreading of HLB in the grove.
Citrus canker is a disease, which causes dropping of fruits, defoliation during
highly favorable conditions for contamination. Dewdney and Graham (2009) reported a
brief idea about citrus canker management such as protecting canker free areas by
decontamination, tree removal, defoliation, pruning, copper sprays and leaf miner
control. The leaves and twigs of the citrus trees need to be safely disposed within the
same grove, in order not to contaminate other areas.
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Debris Generated by Mechanical Citrus Harvester
Mechanical citrus harvesting systems are used in the citrus groves in Florida to
increase harvesting efficiency, and one of the commonly used harvesters is a
continuous canopy shake and catch harvester. The tines of the harvester shake up the
canopy of the tree and the fruit that falls onto a catch frame is fed to the harvester’s
conveyer belt and then transported to trucks following the harvester. The main problem
with this harvester is that along with the fruit, debris objects such as leaves and twigs
are also shaken off the tree and get mixed with fruits, which have to be separated from
the fruit at a later stage. Although, mechanical harvesting is much faster than
conventional hand harvesting and has helped reduce the harvesting cost by 10-20%
(Roka et al., 2009), however approximately 3-4 times more debris mass is collected
using mechanical harvesting (Spann et al., 2007).
These debris lead to increase in transportation and separation cost at later stages
in the juice processing plants. Sometimes big branches are stuck in juice extractors,
and cause expensive repair and maintenance. It was observed that the overall
economic impact of debris mass is approximately $0.10 for each 40.1 kg-box (Patil et
al., 2010) of mechanically harvested oranges. In 2007-08, more than 9.6 million such
boxes were harvested (Roka et al., 2009) which made the total economic impact of
debris material to be equal to approximately $1 million per annum. This is the case
when mechanical harvesting adoption rate is approximately 7% of total acreage.
Considering the 100 % adoption rate in future, the overhead cost due to debris material
can potentially become more than $10 million per annum.
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Labor Productivity
All of the mechanical harvesting systems are projected to increase labor
productivity. The area canopy shakers may double labor productivity in older traditional
groves. The canopy shake and catch harvesters or the trunk shake and catch
harvesters may increase labor productivity by 5 to 10 times that of hand harvesting. The
continuous canopy shake and catch harvesters may increase labor productivity by 10 to
20 times that of hand harvesting. None of the systems have yet achieved their projected
levels of performance. But they eventually will when the machines are durable, operated
by well trained crews in groves that are properly prepared, and the harvesting operation
can work at capacity for a regular 5 or 6 day week.
Needs for Debri Elimination System
In Florida, almost 93% of all oranges are harvested by hand. The pickers dump
the fruit into plastic tubs that hold approximately 408 kilograms of oranges. A special
fruit hauling truck, called a "goat", will then come through the grove and, using a
hydraulic boom, pick up the tub and dump it into the back of the goat. Most
mechanically harvested fruit is harvested directly into a goat truck. The goat truck then
goes outside the block of trees and the harvested oranges into a trailer that holds about
20,412 kilograms of oranges. A truck then hauls the trailer to the processing plant.
Since 1999, the industry has been harvesting a portion of the processed orange
crop with mechanical harvesters. Three types of machines are available for commercial
harvesting, the continuous canopy shake and catch system (CCSC), the trunk shake
and catch system (TSC), and the tractor-drawn continuous canopy shaker (T-CS). In
the last 3 harvesting seasons, however, mechanical harvesting has been done almost
exclusively with the CCSC and T-CS systems. During the 2008-09 season, more than
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35,000 acres and 9.5 million boxes of oranges were mechanically harvested (FDOC,
citrus MH website (citrusmh.ifas.ufl.edu)).
Citrus processing plants have become increasingly concerned about the increased
volume of non fruit debris coming from fruit loads harvested by mechanical harvesting
equipment. It was determined that the best point at which to sample for debris is at the
point where the goat truck dumps harvested fruit into the trailer. This point is common to
all harvest methods and it represents the final step before fruit are delivered to the
processor, thus any debris still with the fruit at this point will be delivered to the
processor. It has been noticed that stems tend to be either relatively small (pencil-size
diameter) or quite large (> 0.0127 meter diameter) (Spann, 2007).
Processing plants argue that the increased volume of harvesting debris from
mechanical harvesting systems impose higher costs on juice plant operations. These
costs include increased repairs to fruit handling equipment, juice extraction equipment,
costs associated with equipment downtime, loss of juice yield, and time and expense to
handle larger volumes of waste material within the plant facility.
Developing a procedure to collect cost data from processing plants proved to be
more difficult than anticipated, in large part to the perceived sensitive nature of the data.
Cost of handling harvesting debris could be a sizable number. At best, knowledge of
this cost could stimulate discussion across the industry (grower + harvester +
processor) to Figure out the least cost solution to remove all harvesting debris prior to
juice extraction. At the very least, knowledge of this cost could facilitate a change in
mechanical harvesting so that debris from mechanical harvested systems dramatically
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decreases, and mechanically picked loads actually become preferred to hand harvested
loads.
Ten processing plants completed the cost surveys for the most recent three
seasons, 2006-07 through 2008-09. The ten plants represented more than 75% of fruit
processed during 2008-09. These plants reported annual number of boxes processed
and average costs per box were calculated on the basis of costs reported associated
with handling debris. Costs per box were calculated and pooled across all plants (10)
and for all years (3). The annual average cost to handle harvest debris was estimated to
be $0.088 per box (Patil et.al. 2009). Seven plants reported processing more than 12
million boxes during the 2008-09 seasons. Given the above cost estimate, these plants
incurred added annual costs of more than $1 million.
Serious measures must be taken to avoid debris entering the processing plant and
mixing with harvested citrus fruits. Hence the debri removal efficiency of citrus canopy
shake and catch harvester should be increased in order to reduce the handling cost of
debris at processing plants.
Objectives
The objective of this research was to quantify the amount of debris generated
during harvesting and determine the indirect estimation of mass using machine vision
for a citrus canopy shake and catch harvester to avoid spreading of diseases like citrus
canker and black spot.
Also to design an efficient debri removal system for testing it at commercial citrus
grove and compare the efficiencies of the newly designed extended de-stemmer in
comparison with currently used regular de-stemmer on the mechanical harvester. The
idea was to find different ways of eliminating debris entering the processing plants. The
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elimination of debris helps the processing plants reduce the downtime cost, labor cost
and increase the productivity. The main purpose of the research was to design and test
the newly designed extended de-stemmer and de-trasher at commercial citrus grove
and compare the results with the laboratory experiments and also to come up with new
designs with cost estimation for installing it on the mechanical harvester.
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CHAPTER 2 LITERATURE REVIEW
Different Types of Mechanical Harvester for Different Crops
Cucumber Mechanical Harvester
The Pik Rite 3100 cucumber mechanical harvester as shown in Figure 2-1 is used
for harvesting cucumbers. The harvester has a 3 meter long throat which inhale crops at
the rate of three acres per hour (Pik Rite, 2010). The harvester separates the cucumber
from leaves, vines and debris, and clean load of harvested cucumber are collected on
the trailer.
Figure 2-1. Pik Rite 3100 cucumber mechanical harvester. (Source: http://www.pikrite.com/. Last accessed June, 2010).
The 200 bushel hopper keeps the operator moving and unloading continuously.
This harvester can operate in adverse conditions.
Pepper Harvester
The Pik Rite mechanical harvesters as shown in Figure 2-2 are being used
successfully to harvest bell peppers, banana, jalapeno and hot cherry peppers. This
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harvester can harvest up to 7,258 kilograms of bell peppers per hour by reducing the
labor cost and increase the productivity of the harvester (Pik Rite, 2010). The sickle bar
header is designed to work in raised beds or on flat ground to achieve crop recovery. An
optional disk header is available. These types of headers can work with single or double
rows.
Figure 2-2. Pik Rite pepper mechanical harvester. (Source: http://www.pikrite.com/. Last accessed June, 2010).
The mechanical harvester consists of an optional rear cleaning table which allows
the workers to clean the vegetables or fruits remaining on the vines after passing
through the shakers. This harvester can load boxes, dump carts or semi trailers. The
discharge elevator is fully functional at heights up to 0.27 meters.
Chili Pepper Harvester
The mechanical harvester shown in the Figure 2-3 has an enclosed pressurized
inspection area designed to accommodate a crew when necessary. It is equipped with
rock separator and individual speed controls for each conveyor that separates rocks
and other debris collected during harvesting. A rotating star cleaning table separates the
stalks from the peppers. The two-row stripper heads can be adjusted for 30-40 inch
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rows and this system strips the peppers from the stalk and combs the soil by lifting the
peppers off of the soil bed.
Figure 2-3. Pik Rite chili pepper mechanical harvester. (Source: http://www.pikrite.com/. Last accessed June, 2010).
Tomato Mechanical Harvester
The HC290 Tomato Harvester is a high-capacity mechanical harvester that can
harvest up to 60 to 80 tons per hour, reducing the tomato harvesting time and labor
costs and increasing the profits of the tomato growers.
Figure 2-4. Pik Rite tomato mechanical harvester. (Source: http://www.pikrite.com/. Last accessed June, 2010).
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The harvester as shown in Figure 2-4, equipped with an NFM Sorter from Odenberg,
electronic controls, and a forced balance shaker system, which can be used to recover
excellent grades of harvested fruits and vegetables.
Corn Head Used to Minimize Debris
The 50 Series cornhead as shown in the Figure 2-5, is the most demanding
harvester equipment during the harvesting conditions and has been built to perform in
industries where there is no downtime. The corn head consists of an exclusive knife roll
design which provides a clean cut and exceptional residue management. These knife
rolls deliver stalk flow, straight pull-down engagement, and stalk conditioning that result
in high corn yield and less debris (OXBO, 2010).
Figure 2-5. The 50 series cornhead used to eliminate debris. (Source: http://www.oxbocorp.com/. Last accessed January, 2008).
The cornhead is hydraulically adjusted, beveled stripper plates that remain
centered over the knife rolls promoting straight down stalk flow, gentle corn removal,
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and less plugging. The combination of these features cut the corn cleanly off the stalk
and minimizes trash and corn damage.
Greens Cutting Head
The innovative greens cutting head is a new design which is installed on the GH80
as shown in Figure 2-6, with a parallel link float system that eliminates the need for a full
width ground roller allowing re-growth of the crop for operations that employ multiple cut
harvesting.
Figure 2-6. The greens cutting head on the GH80. (Source: http://www.oxbocorp.com/. Last accessed January, 2008).
The helix auger transfer design the green cutting head allows a very wide air gap
for elimination of dirt clods, field debris, vermin, and other foreign objects (OXBO,
2010). A constantly compensated tensioning system on the endless band blade helps in
consistent cutting performance. The features of the harvester combines to give a
reduced tearing, fraying, and dropped product on the bed surface and helps improve the
quality on the second and third cuttings.
Citrus Mechanical Harvesting Systems
Mechanical harvesting systems harvested more than 17,000 acres of Florida citrus
in the 2002-03 seasons (Futch et.al. 2005). Mechanical harvesting systems encompass
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a collection of technologies that hold significant potential to reduce harvest costs, lessen
demand for manual harvest labor by 90%, and create job opportunities for a new skilled
work force. Savings generated from mechanical harvesting will allow Florida citrus
growers to remain economically competitive within the global market place for orange
juice and will offset rising costs from cultural management strategies. Growers who
have adopted mechanical harvesting have lowered harvesting costs by 10-20% as
compared to conventional hand harvesting. Widespread adoption of mechanical
harvesting is predicted to save growers more than 50% over current harvesting costs
and reduce concerns with labor availability (Roka et al., 2009). Despite the current and
potential cost savings, many growers have been slow to embrace mechanical
harvesting and the adoption rate of mechanical harvesting has reached a plateau at
seven percent of total acreage.
Mechanically harvested acreage decreased during the 2007-08 season by 9%
from the previous year. The number of boxes mechanically harvested, however,
increased by more than 1.3 million (Roka et al., 2009). Three commercial mechanical
harvesting systems have operated in Florida since 2000: continuous canopy shake and
catch (CCSC), tractor-drawn canopy shaker (T-CS), and trunk shake and catch (TSC).
Tractor Drawn Canopy Shake
The tractor drawn canopy shaker (T-CS), manufactured by Oxbo, utilizes a
shaking head identical to the shaking unit on the self propelled CCSC. Shaker heads
penetrate the canopy and vibrate up and down and side to side to remove fruit. During
the 2004-05 seasons, a T-CS shook fruit to the ground and then utilized a hand crew to
gather the fruit into traditional 10-box tubs. A field truck or goat would then dump the
tubs and transport the fruit to the bulk trailers. A T-CS system travels between 1 and 2
28
mph down the row. Its daily use, however, is constrained by the availability of workers to
pick-up the fruit.
A big advantage of a T-CS system over its self-propelled counterpart is that trees
do not have to be skirted or grown within long rows of uniform sized trees. Since harvest
workers do need ladders, labor productivity is improved by at least 2 fold (between 20-
30 box/hr), Figure 2-7.
Figure 2-7. Tractor drawn canopy shake, tines penetrating the canopy. (Source: http://citrusmh.ifas.ufl.edu/index.asp. Last accessed January, 2009).
In trees that yield between 3 and 3.5 boxes/tree, performance statistics for a T-CS
average removal of fruits about 95%, recovery of 99% ( pick-up crew gleans reachable
fruit), machine speed of 300-400 tree/hr assuming no downtime and labor productivity of
20-30 boxes/hour/crew member (IFAS, 2010).
Trunk Shake and Catch Harvest Systems
One trunk shake and catch set (TSC) includes a minimum of three machines as
shown in Figure 2-8, one shaker unit, one receiver unit, and one field truck (goat).
Sometimes one goat can service two TSC units. The shaker unit attaches to the trunk of
a tree and shakes the tree for between 5 and 10 seconds. Falling fruit is deflected into
29
the receiver that conveys the fruit to a cart attached to the receiver. The cart can hold
between 70 and 90 boxes (90-pounds/box), after which the fruit is dumped into the field
truck for transport to the bulk trailer.
The TSC system is well suited for long rows and uniform sized trees. Trees need
to have a clear trunk of at least 12 inches and should be “skirted” to allow optimal fruit
collection.
Figure 2-8. Trunk shake and catch harvester. (Source: http://citrusmh.ifas.ufl.edu/index.asp. Last accessed January, 2009).
On trees that have been skirted and average between 3 to 3.5 boxes per tree,
performance measures average removal of fruits about 95%, recovery of 90%, machine
speed of 235 tree/hr assuming no downtime and labor productivity of 90
boxes/hour/crew member (IFAS, 2010).
Continuous Canopy Shake and Catch Harvest Systems
One continuous canopy shake and catch set (CCSC) includes a minimum of four
machines--two harvesting units and two field trucks (goats) into which fruit is conveyed.
Most systems engage 2 additional field trucks that allow transport of fruit to the bulk
trailers without stopping the harvesting operation. Harvesters work in parallel on either
side of the tree row. Good synchronization allows the two harvesters to minimize fruit
30
drop to the ground. A CCSC system travels between 1 and 2 mph down the row.
Shaker heads penetrate the canopy and vibrate up and down and side to side to
remove fruit. Fruit falls on to a catch frame and is conveyed to a trailing field truck.
CCSC system as shown in Figure 2-9, is well suited for long rows and uniform
sized trees. Trees have to be “skirted” to allow optimal fruit collection. On trees that
have been skirted and average between 3 to 3.5 boxes per tree, removal of fruits about
95% and recovery of 90%, machine speed of 450-500 tree/hr assuming no downtime
and labor productivity of 100 boxes/hour/crew members (IFAS, 2010).
Figure 2-9. OXBO - Continuous canopy shake and catch harvester. (Source: http://citrusmh.ifas.ufl.edu/index.asp. Last accessed January, 2009).
Up until the 2004-05 seasons, Oxbo and Korvan were two manufacturers of CCSC
equipment. Korvan has since discontinued production, leaving Oxbo as the only
manufacturer of CCSC systems. Abscission Agent
The introduction of an abscission agent will selectively loosen fruit and generate
more debris during harvesting. During May and June mechanical harvesting can
inadvertently remove young developing ‘Valencia’ fruit and reduce next year’s yield by
as much as 50% Roka et al. (2009). Many commercial industry and grower cooperative
31
members believe that a suitable abscission agent would solve the late season
harvesting challenge. A suitable abscission agent will selectively loosen mature fruit so
that reduced mechanical shaking frequency can be used to harvest. With an abscission
agent application, mechanical harvesters will be able to operate at a lower intensity,
thus leading to a reduction in cosmetic tree damage. This improvement in the
harvesting process should help lessen grower concerns about adverse effects from
mechanical harvesting on crop yields and tree health. An additional benefit of reducing
harvesting intensity in combination with the loosening effect of an abscission agent is
the delivery of cleaner loads of fruit to the processing facilities due a reduction in limb
and leaf debris. A suitable abscission agent will selectively loosen mature fruit so that
reduced mechanical shaking frequency can be used to harvest. In doing so, mature fruit
selectively loosened with an abscission agent will be harvested, while young fruitlets will
not be removed and next year’s yield will be preserved.
Reducing Debris in Trailer Loads by Using Abscission Agent
The shaking mechanism that effectively harvests mature citrus fruit can also
remove large quantities of leaves and stems, or dead branches (collectively termed
“debris”) (Roka et.al., 2009). Debris makes its way into loads of fruit delivered to the
processor. Some of this debris can be eliminated via de-stemmers on the harvest
machinery, but these devices cannot remove all debris and not all processing machines
are equipped with de-stemmers. Each pound of debris that makes its way into a load is
one less pound of fruit that can be hauled in that load, thereby increasing transport
costs. The increased volume of debris flowing into processing plants from mechanical
systems increases the operational costs of the feed mill (Spann, 2007). CMNP-treated
32
fruit have fewer attached stems and leaves, and overall fruit loads have significantly
less debris than untreated hand and mechanically harvested loads.
Improvements in equipment design to eliminate unwanted debris coupled with the
use of CMNP should alleviate concerns about excess debris at the processing plant.
Currently, processing plants assess additional fees or charges on harvested loads that
transport an excessive amount of debris. The added fees compensate the processing
plant for their added costs in debris handling. Results showing that CMNP reduces
overall debris should lead to lower processing costs and more favorable acceptance of
mechanically harvested loads (Roka et.al. 2009).
33
CHAPTER 3 IMAGE PROCESSING
Why Image Processing?
The importance of image processing in citrus fruit mechanical harvesting was that
the debris were properly disposed of within the grove, so that no disease was spread to
other locations and citrus processing plants were protected from being damaged due to
big branches. Machine vision techniques find many applications in agricultural
automation for disease detection, yield mapping, and many other applications.
Chinchuluun et al. (2007 and 2009) reported a citrus yield mapping system that used
machine vision to count the number of fruits and estimate fruit quality in a continuous
canopy shake and catch harvester. Detection of debris using images is a very important
application of machine vision. This is a safer practice than manually handling diseased
vegetation.
Hardware for Machine Vision
The machine vision system (Figure 3-1) consisted of a pair of Firewire color
cameras (IMC-11FT, Imi Technology, Seoul, Korea) which were initially adjusted to get
a high quality image and three halogen lamps (MR-16, Master Line Plus 50W GU5.3
12V 38D, Phillips Electronics) installed inside a camera box to get sufficient illumination,
which was mounted on top of the conveyor system of a test bench for capturing images
during experiment.
The camera and halogen lamp were installed inside a camera box in Figure 3-1,
made of thin sheet metal with size of 0.99 m x 0.41 m x 0.51 m.
34
A B
Figure 3-1. Image acquisition systems. A) Firewire cameras. B) Halogen lamps.
Software
Debri detection system for a citrus canopy shaker and catch harvester using
machine vision was used, which was reported by Lee et al. (2008), and a C++
application using Microsoft Visual Studio (v6.0) was developed to control the interface
with the camera drivers. The camera drivers converted the raw data to bitmap format
and the program saved the file in an external hard drive (My book, Western Digital, Lake
Forest, CA). The application controlled the rate of capturing images and stored the
images on the external hard drive. The application also provided an interface to change
the camera settings such as brightness, sharpness exposure, and shutter speed.
Image Processing
Detection of debris using machine vision is completely an automated system
which identifies the size of debris and quantifies the amount of debris (leaves/twigs) that
can be disposed in the citrus grove during harvesting process. The machine vision
system can limit spreading of diseases such as citrus greening and citrus canker to
citrus trees outside the grove and save labor cost and time. After the final images were
captured and collected, all images were analyzed to quantify the amount of debris. In
image processing, images were acquired for calibration, training and validation of the
35
algorithm. Calibration is the process of mapping the pixel area of debris to the mass.
Training is the process used to identify the appropriate threshold values for image
segmentation and other parameters for morphological operations to separate debris
from initial images. Validation is the way to evaluate the performance of the algorithm
using a certain set of images which are neither part of calibration nor of training set.
A total of 20 images were taken to calibrate the debris with actual mass as shown
in table 3-1 and 3-2. Calibration sets consisted of fruits, leaves and twigs of different
sizes and masses which were chosen to represent the entire range of sizes and
masses. These sets were used to map pixel information to actual mass using
regression analysis and the regression equations were further used to estimate the
mass of debris in the validation set images.
A total of 12 tests (419 images from each camera) were conducted out of which 1st
set of (34 images from each camera) was used for training and the remaining 309
images from each camera were used to validate the debris estimation algorithm. In
each test, different amount of oranges, leaves, and twigs were mixed together, fed into
the test bench manually while the conveyor belt was rotating, and their images were
acquired every second. Figure 3-2, shows an example binary image of leaves and
twigs.
A B
Figure 3-2. Images captured for image processing. A) Original image of debris. B) Corresponding binary image.
36
Table 3-1. Calibration of fruit samples Fruit Data
Sample Number Mass (Kg) Pixel Area (Pix)
Diameter (Pix)
Average D (meter)
1 0.321 4640 76.86 0.083 2 0.289 3942 70.84 0.081 3 0.302 3678 68.43 0.079 4 0.296 4553 71.43 0.083 5 0.295 4529 68.89 0.081 6 0.256 4008 71.43 0.078 7 0.251 3728 68.89 0.077 8 0.246 3517 66.91 0.079 9 0.222 3470 66.46 0.076 10 0.213 3426 66.04 0.075 11 0.206 3324 65.05 0.074 12 0.201 3108 62.9 0.072 13 0.188 2717 58.81 0.072 14 0.170 2830 60.02 0.070 15 0.169 2989 61.69 0.069 16 0.157 2844 60.17 0.068 17 0.167 2782 59.51 0.068 18 0.150 2484 56.23 0.068 19 0.134 2304 54.16 0.063 20 0.117 2191 52.81 0.060 21 0.123 2189 52.79 0.060 22 0.122 2176 52.63 0.061 23 0.104 1993 50.37 0.059 24 0.102 1935 49.63 0.060
Image Processing Results
From the calibration images, regression analysis was performed between the
predicted mass of the debris and pixel area in the binary images as shown in the Table
3-3, where the coefficient of determination (R2) was 0.96 between actual mass of fruit
and debri materials and their sizes in images. Predicted actual mass in kilograms was
obtained from the regression equation. Linear regression equation was obtained in
order to find out the indirect mass of debris.
37
Table 3-2. Calibration of debri samples Sample Number
Actual Wt (Kg) Pixel Area
1 0.453 171844 2 0.310 113992 3 0.184 83220 4 0.132 57672 5 0.122 58986 6 0.071 38072 7 0.052 15436 8 0.024 25071 9 0.028 14671 10 0.018 10146 11 0.016 6573 12 0.056 3662 13 0.007 2825 14 0.006 4479 15 0.003 2918 16 0.00136 2605 17 0.00149 2347 18 0.00086 2492 19 0.00018 2252 20 0.00002 4070
Table 3-3. Predicted mass and pixel area for regression analysis Predicted Mass in (kg) Area (Pixel)
2.52 98478 1.53 63003 1.71 57330 4.86 169936 5.04 111826 5.58 125428 5.94 162906 6.93 189519 6.48 170632 6.57 198074 7.2 238591 6.39 198794
From the validation images, regression analysis was performed between the
predicted mass of the debris and pixel area in the binary images. The images of debris
38
was taken during actual experiment were converted into binary images using Matlab
programming and pixel area was obtained. From the obtained data, regression analysis
was conducted and the value of R2 was 0.84.
Predicted actual mass was obtained from the regression statistics. Linear
regression equation was obtained in order to find out the indirect mass of debris. The
graph of predicted actual mass of debris vs. pixel area was plotted to find the trend. The
graph as shown in Figure 3-3, shows the correlation between predicted actual mass
and pixel area.
Figure 3-3. Predicted actual mass vs. pixel area.
The R2 value of experimental images was 0.84 between the predicted actual
mass with pixel area in the images.
39
CHAPTER 4 MATERIALS AND METHODS
Hardware for Regular and Extended De-stemmer
A test bench from OXBO is an end part of the continuous canopy shake and
catch mechanical harvester which has a conveyor belt that carries the fruits to the semi-
trailers passing through the de-stemmer. The test bench consists of a conveyor belt,
reverse moving conveyor belt and de-stemmer. The reverse moving conveyor is
mounted between the de-stemmer and the regular conveyor belt. The reverse moving
conveyor moves in the opposite direction of the regular conveyor belt and it helps
remove light debri which are thrown in the backward direction.
Two different types of de-stemmers were used for conducting debri removal
experiment. A regular de-stemmer in Figure 4-1, with a set of ten 0.61 meters long
rollers that are currently used by the mechanical harvester and an extended de-
stemmer in Figure 4-1, with a set of ten 0.91 meters long rollers were used. A de-
stemmer has set of rollers which are rotating in the opposite direction of each other. The
rollers consist of grooves which help catch debris while they are passing through the de-
stemmer and separate debris from citrus fruits. As the fruits and debris pass through the
de-stemmer, the debris are caught in the grooves and pulled down.
A B
Figure 4-1. De-stemmers used for the experiment. A) Regular de-stemmer with the roller lengths of 0.61 m. B) Extended de-stemmers with the roller lengths of 0.91 m.
40
A hydraulic motor (In-line hydraulic tester, Owatonna Tool Company, Minnesota)
was used as a power source to run the conveyor belt and de-stemmer. Test bench, a
laptop computer (Latitude, Dell) for acquiring images, weighing scale (HDM753DQ-95
A319BN, Sunbeam Products, Inc.) were additional tools used to conduct the
experiment. These components are presented in Figure 4-2.
Figure 4-2. Hardware components used for conducting the experiment.
Catch Frame De-trasher Modification
A catch frame is a major part of the citrus canopy shake and catch harvester.
The harvested fruits and debris fall on the catch frame of a citrus canopy shake and
catch harvester. Currently, the catch frame has a solid base and there is no place for
the debri samples to be separated from the harvested citrus fruits. The modified catch
frame de-trasher consists of a de-stemmer which removes the debri when they initially
41
fall on the catch frame during harvesting. The typical and modified catch frames are
indicated in Figure 4-3.
A B
C D
Figure 4-3. Catch frame modification. A) Typical catch frame on a mechanical harvester. B) The catch frame on a mechanical harvester with fruit and debris. C) The front view of the modified catch frame. D) Side view of the modified section of a catch frame.
Testing Extended De-stemmer and De-trasher at Commercial Citrus Grove
The extended de-stemmer and de-trasher were taken and installed on one of the
citrus canopy shake and catch mechanical harvester as shown in the Figure 4-4 to test
the efficiency of regular and extended de-stemmer.
42
A B
Figure 4-4. Field experiment setup. A) Disassembling the regular de-stemmer. B) Installation of extended de-stemmer on the mechanical harvester.
Two different types of de-stemmers were used for conducting debri removal
experiment. A old regular de-stemmer with a set of ten 0.61 meters long rollers that
were currently used by the mechanical harvester were replaced by the extended de-
stemmer with additional set of ten 0.91 meters long rollers as shown in the Figure 4-5
below.
A B
Figure 4-5. De-stemmer used for the experiment. A) Regular used de-stemmer B) Extended new de-stemmer.
A de-stemmer installed on a mechanical harvester has a set of rollers which are
rotating in the opposite direction of each other. The rollers consist of groves which help
43
rollers in catching of debris while passing through de-stemmer and separate debris from
citrus fruits. As the fruits and debris pass through the de-stemmer, the debris was
caught in the groves and pulled down. The extended de-stemmer installed on one of the
mechanical harvester and the citrus fruits collected on a goat truck are shown in the
Figure 4-6.
Figure 4-6. Working of extended de-stemmer on the mechanical harvester and citrus fruits collected in a goat truck.
At the time of post harvesting, some amount of debris were collected along with
citrus fruits in the goat truck. To minimize the amount of debris shipped to the
processing plant, a pickup machine was modified by installing a hopper on it along with
de-trasher and conveyor belts to eliminate more amount of debris which is collected
during post harvesting and obtain debri free load of harvested citrus fruits. The de-
trasher consists of a hopper which has a capacity of approximately 90 boxes where the
fruit and debris were unloaded from the goat truck as shown in the Figure 4-7.
44
.
Figure 4-7. Experimental setup at the citrus grove, goat truck unloading harvested citrus fruits into the hopper.
The gate of the hopper was hydraulically operated for opening and closing. The
feeding of fruits and debris to the conveyor belt was controlled by the opening and
closing of the gate. Load cells were used to measure the mass of the hopper. The load
cells were installed on the four corners of the hopper and the mass of fruit and debris
was displayed on the screen as shown in the Figure 4-8 below.
A B
Figure 4-8. Weighing of fruit and debri samples. A) Load cell to measure the mass of fruits and debris in the hopper. B) Mass displayed on the digital screen.
Hopper
End Conveyor Belt
Goat Truck
Load Cell
De-Trasher
45
A slow conveyor belt moving in the opposite direction of the slope was installed
at the end of the conveyor belt below the opening of the hopper. This conveyor belt was
used to remove big size twigs which cannot be removed by the de-stemmer and may
cause a major break down at the processing plant. The conveyor belt is tilted at an
angle such that the fruits roll down on the next moving conveyor belt and big twigs and
small debris were eliminated due to their light mass compared to the mass of the fruits
as shown in the Figure 4-9.
Figure 4-9. Debri removal conveyor belt installed at the end of the feeding conveyor belt inclined at an angle to remove big twigs.
Apart from the conveyor belt, a newly designed de-trasher was installed on the
pickup machine to eliminate maximum amount of debris generated during post
harvesting. The de-trasher consists of a set of de-stemmers moving in the opposite
direction at high speed. The de-trasher was installed on the pickup machine at a slightly
tilted slope approximately 15 to 20 degrees horizontally allowing the citrus fruits and
debris to move freely on the de-trasher as shown in Figure 4-10. As the fruits and debris
pass through the de-trasher, the fruits roll on to the next conveyor belt and debris are
caught in between the groves of the de-trasher and were eliminated.
46
Figure 4-10. Newly designed de-trasher installed on the pickup machine to test the debri removal efficiency.
The debris was collected underneath the de-trasher and the conveyor belt where
the mass of debris was measured using a weighing scale (Mettler Toledo, PBA 220
Weighing Platform) as shown in the Figure 4-11.
Figure 4-11. Weighing platform to measure the mass of debris removed by the conveyor belt and de-trasher.
47
Experiments
Lab Experiment to Compare the Efficiency of Regular and Extended De-stemmer
The experiments were conducted in the Agriculture and Biological Engineering
machine shop at the University of Florida campus. Initially different size of fruit and
debris were collected and sorted out for size calibration in the images. Corresponding
diameter and mass of fruit samples were measured using a calipers (S1148F, Summit)
and a scale (Adventure, SN: G0631201390479, OHAUS Corp, USA), respectively. After
the required data was collected, baskets of different fruit and debris were prepared and
their mass was measured. There were two types of samples used for the experiment.
One type of samples contained both fruit and debris as shown on the left hand side of
Figure 4-12, whereas the other type contained only debri samples shown on the right
hand side in Figure 4-12. The actual mass of debri samples was measured initially
when the fruit and debris sample baskets were prepared. The fruit and debri samples
were fed on the conveyor belt. The debris were separated by the de-stemmer and only
fruit were collected at the end of the test bench. The fruit mass was measured
separately and the difference in mass between the basket of fruit and debris materials
combined before feeding on the conveyor belt was collected. The mass of only fruit
samples was collected after feeding on the conveyor belt which was noted as the actual
mass of debri samples. Initially, one basket of fruit and debri samples were fed on the
conveyor belt and mass of fruit and debri samples was collected. This step was
repeated three times. Similarly, two baskets, three baskets and four baskets were fed
on the conveyor belt and mass of fruit and debri samples were noted down. This step
was also repeated three times. In the second part of the experiment, one basket of only
debri samples were fed on the conveyor belt and this part was repeated four times.
48
A B
Figure 4-12. Fruit and debri samples used for experiment. A) Mixed sample of fruit and debris. B) Only debri samples.
Simultaneously, the camera system was started and images were acquired for
further image analysis. Finally a t-test was conducted to compare the performance of
both de-stemmers. Let μ₁ be the amount of debris removed by the regular de-stemmer
and μ₂ is the amount of debris removed by the extended de-stemmer. The null
hypothesis, Hο, was defined as the amount of debris removed by the regular de-
stemmer was equal to the amount of debris removed by the extended de-stemmer (μ₁-
μ₂ =0). The alternative hypothesis Hα was that the amount of debris removed by the
regular de-stemmer was less than the debris removed by the extended de-stemmer (μ₁-
μ₂< 0). The significance level (α) was 0.05. The results were obtained using the data
analysis tool pack in Microsoft Excel and efficiency of both de-stemmers was compared.
Catch Frame De-trasher Modification Experiment
Two sets of experiment were conducted in the Agricultural and Biological
Engineering machine shop at the University of Florida. The first set included the
removal of petioles from fruit samples. The length of petioles was divided into less than
0.05 meters and greater than 0.05 meters. The fruit samples are shown below in Figure
4-13. The second set includes the separation of debris from the mixture of citrus fruits.
49
Fruit and debri sample baskets were prepared and their mass was recorded. The fruit
and debri samples were fed on the de-trasher and corresponding mass of separated
debris samples and fruit samples were also weighed and recorded. This procedure was
repeated 12 different times and corresponding data was obtained.
Figure 4-23. Fruit samples with different lengths of petioles.
De-trasher Modification Experiment at Commercial Citrus Grove
The experiment was conducted at a commercial citrus grove (Lykes Grove)
located in Ft Basinger, Florida and different loads of harvested fruits and debris from
regular and extended de-stemmer were collected in a goat truck and their combined
mass was measured. The mass of the goat truck with a load of fruit and debris was
measured on a truck weighing scale. A pair of truck weighing scale was installed on a
flat surface and the mass of front and rare axle was noted down separately as shown in
the Figure 4-14 below.
50
A B
Figure 4-14. Measuring the mass of the goat truck with load and with no-load. A) Measuring front axle. B) Measuring rare axle.
The mass of the goat truck was measured for both cases, with load and with no-
load. The mass of the goat truck was also measured for the loads of fruit with no debris
and only fruit samples. The fruits and debris were unloaded in the hopper which is
mounted on the de-trasher. The initial mass of the hopper was measured on the load
cell and the mass is displayed on the digital monitor.
Table 4-1. Mass of fruits and debris for regular and extended de-stemmer
Observations
Mass of Fruits and Debris (Kg)
(Regular De-Stemmer)(Load Cell)
Mass of Fruits and Debris (Kg)
(Extended De-Stemmer)(Load Cell)
1 498 1018 2 493 1068 3 491 1145 4 959 459 5 814 1134 6 882 1966
Net Total Mass 4136 6791
The gate of the hopper was opened slowly such that the fruits and debris were
fed on the conveyor belt. The fruit and debris were carried on from one conveyor belt to
51
another and then passing through the de-stemmer and finally to the empty goat truck as
shown in the Figure 4-15 below.
This process was carried out for two different loads with three different mass
values of fruit and debris obtained from regular and extended de-stemmer and
corresponding data was obtained. The mass of the goat truck with clean fruit samples
was measured on the truck weighing scale.
The debris were separated by the de-trasher and only fruit samples were
collected at the end of the conveyor belt of the pickup machine. The fruit mass was
measured separately and the mass difference between the fruit and debris combined in
the goat truck before feeding on the de-trasher and mass of only fruit samples collected
after feeding on the de-trasher was the actual mass of debris eliminated by the de-
trasher.
A B
C D
Figure 4-15. Experimental setup. A) Fruit and debris unloaded in the hopper. B) Fruit and debris passing on the conveyor belt after the release of hydraulic operated gate of the hopper. C) Fruit and debris passing through the de-trasher. D) Clean load of fruits on the end conveyor belt loading the goat truck.
52
CHAPTER 5 RESULTS AND DISCUSSION
Comparison between De-stemmers
After the experiment, the amount of debris removed by the extended de-stemmer
was compared to those by the regular de-stemmer. The following Figure 5-1 shows the
debri removal efficiency by the extended de-stemmer compared to the regular de-
stemmer.
A B
Figure 5-1. Comparison between amount of debris removed. A) Regular de-stemmer. B) Extended de-stemmer.
The t-test results are listed in table 5-1 below.
Table 5-1. Results obtained from t-test.
Percentage of debris removed by the
regular de-stemmer (%)
Percentage of debris removed by the extended
de-stemmer (%)
Mean 4.93 6.91 Variance 5.66 9.56
Observations 12 12 Pooled Variance 7.61
Degree of freedom 22 t Stat -1.76
P(T<=t) one-tail 0.045 t Critical one-tail -1.71
53
Since the value of t-stat is less than t-critical (-1.76<-1.71) and p-value less than
0.05, the alternate hypothesis Hα was accepted, which concludes that the amount of
debris removed by the extended de-stemmer was more than those removed by the
regular de-stemmer.
The efficiency of both de-stemmers was also compared by the percentage of
debris removed from the total amount of input fruit and debri samples as listed in the
table 5-2 below.
Table 5-2. Percentage of debris eliminated by regular and extended de-stemmer. Percentage of Debris Removed Percentage of Debris Removed
by the Regular De-Stemmer by the Extended De-Stemmer 2.25 13.36 8.37 4.29 8.29 1.95 3.05 6.04 4.95 4.50 3.48 7.31 7.79 9.21 6.04 6.31 4.81 9.56 2.13 8.44 5.88 3.90 2.08 8.05
From graphical representation of debri removal efficiency Figure 5-2, it was
observed that the debris removed by the extended de-stemmer was higher as
compared to regular de-stemmer. However, at cycles 2, 3, 5 and 11, it was observed
that the debris removed by the regular de-stemmer was more as compared to extended
de-stemmer because the debris were not removed by the spinner but was removed by
conveyor belt which moves in the opposite direction, as mentioned previously and
debris were removed efficiently. Another reason was the quantity and mass of fruit and
54
debri samples fed on the conveyor belt was not the same for every cycle. It was noted
that at these cycles more quantity of fruit and debris were fed on the conveyor belt for
the testing of the regular de-stmmer and less quantity of debris for extended de-
stemmer.
Figure 5-2. Comparison of debri removal efficiency for fruit and debris with cycles 1-3 is one basket of fruit and debris that were fed on the conveyor belt three times, cycles 4-6 is two baskets of fruit and debris that were fed on the conveyor belt three times, cycles 7-9 is three baskets of fruit and debris that were fed on the conveyor belt three times and cycles 10-12 is four baskets of fruit and debris that were fed on the conveyor belt three times.
With only debri samples, the efficiency of the de-stemmers was also compared
by the percentage of debris removed by the spinner from the total amount of only debri
samples fed on the conveyor belt.
Table 5-3. Percentage of debris removed by regular and extended de-stemmer.
Percentage of Debris Removed by the Regular
De-Stemmer
Percentage of Debris Removed by the Extended
De-Stemmer
8.8 9.5 3.9 7.6 7.1 8.3 6.0 8.8
55
From Figure 5-3, it was observed that the debris removed by the extended de-
stemmer was higher as compared to regular de-stemmer for only debris samples. Only
debris were fed on the conveyor belt in order to find the debri removal efficiency of both
de-stemmers.
Figure 5-3. Comparison of debri removal efficiency with only debri samples.
Catch Frame De-trasher Results
The fruits having petioles less than 0.05 meters were separated and fed on the
modified catch frame. Initially, a set of five fruits were fed on the modified catch frame
and it was noted that how many fruits’ petioles were removed by the de-stemmer on the
catch frame.
56
Table 5-4. Stem removal analysis for length less than 0.05 meter and greater than 0.05 meter.
Stem Removal Analysis Observations Number of
fruits Stem
Removed Stem Not Removed
% of Stem Removed
Stem length 1 5 3 2 60 less than 0.05
meters 2 5 2 3 40
3 5 4 1 80 4 5 5 0 100 5 5 5 0 100
Stem length 6 5 5 0 100 greater than 0.05
meters 7 5 3 2 60
8 5 4 1 80 9 5 4 1 80 10 5 4 1 80 11 5 5 0 100 12 5 4 1 80
The fruits samples before and after the experiment are represented below in Figure 5-4.
A B
Figure 5-4. Fruit samples used for experiment. A) Before being fed on the modified catch frame. B) After being fed on the modified catch frame.
Another set of five fruits, whose petiole length greater than 0.05 meters were fed
on the catch frame and similar results were obtained. The experiment was repeated
twelve times and corresponding percentage was calculated to find out the petiole
removal by the catch frame.
57
Table 5-5. Debris elimination analysis for catch frame de-trasher. Debri Removal Analysis (Kgs) REP1 REP2 REP3 REP4 REP5
Total Mass of Basket 10.78 13.14 15.76 13.14 13.68 Mass of Fruits after Experiment 8.15 10.24 13.95 10.42 11.51
Total Mass of Debris 2.63 2.90 1.81 2.72 2.17 Amount of Debris Not Removed 0 0 0.020 0 0.005
Mass of Debris from De-stemmer 2.63 2.90 1.79 2.72 2.17 % of Debris Removed by the De-
Stemmer (Catch Frame) 100 100 98.9 100 99.8 Debris Removal Analysis REP6 REP7 REP8 REP9 REP10
Total Mass of Basket 15.22 14.13 15.86 13.32 14.22 Mass of Fruits after Experiment 13.32 12.05 14.13 11.05 12.14
Total Mass of Debris 1.90 2.08 1.72 2.27 2.08 Amount of Debris Not Removed 0 0 0 0 0
Mass of Debris from De-stemmer 1.90 2.08 1.72 2.27 2.08 % of Debris Removed by the De-
Stemmer (Catch Frame) 100 100 100 100 100
Figure 5-5 illustrates the efficiency of petiole removal by the modified catch
frame de-trasher. The first two observations represent the stem removal efficiency
which is averaged to 50% for the fruit samples less than 0.05 meters and the remaining
observations represent the stem removal efficiency which is averaged to 86% for the
fruit samples more than 0.05 meters. Only the first two observation were tested for
petiole less than 0.05 meters to test the applicability of the modified system and stem
removal efficiency for small petioles.
Figure 5-5. Stem removal efficiency with observations 1-2 were for fruit samples with petioles less than 0.05 meters and 3-12 were for fruit samples with petioles greater than 0.05 meters.
58
Another experiment was conducted ten times using both fruit and debris together
and it was noticed that a large percentage of debris was separated by the modified
catch frame de-trasher. The citrus fruits and debris were prepared and fed on the catch
frame. It was observed that major amount of debris was separated by the catch frame
de-trasher and only fruits were collected at the end of the catch frame in a basket.
Figure 5-6 indicates the separated debris and fruits collected at the end of catch frame.
A B
Figure 5-6. Catch frame modification experiment. A) Debris separated. B) Fruits and debris samples separated during the experiment.
It was observed that at certain points, amount of debris not removed by the de-
stemmer was very minimal. The efficiency of the catch frame de-stemmer was 99.86%
and standard deviation of 0.356 of the total debris and fruit samples input. The amount
of debris removed by the modified catch frame de-stemmer was very high and this
system can be implemented on the harvester to increase the efficiency of debri removal.
Modified Extended De-stemmer and De-trasher Results at Citrus Grove
The efficiency of the extended de-stemmer was tested by calculating and comparing the
total amount of debris received from the regular de-stemmer load with total amount of
debris received from the extended de-stemmer load as shown in the table 5-7.
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Table 5-6. Total amount of debris received from regular and extended de-stemmer truck load.
Observations
Total Amount Of Debris Received From
Regular De-Stemmer Load (Kgs)
Total Amount Of Debris Received From
Extended De-Stemmer Load (Kgs)
1 0.64 2.42 2 0.66 3.04 3 1.82 0.38 4 1.72 1.22 5 2.5 1.18 6 3.86 2.6
Total Mass of Debris
11.2
10.84
The overall percentage of debris received from regular de-stemmer and
extended de-stemmer load was calculated and it was concluded that the extended de-
stemmer was more efficient in debri removal compared to the regular de-stemmer.
It was observed that 0.21% of debris from the total mass of fruit and debris was
received from the first load of regular de-stemmer compared to 0.18% of debris from the
total mass of fruit and debris was received from the first load of extended de-stemmer.
Therefore the amount of debris received from the extended de-stemmer was less
compared to the regular de-stemmer. For the second load, it was observed that 0.30%
of debris from the total mass of fruit and debris was received from the regular de-
stemmer load compared to 0.16% of debris from the total mass of fruit and debris from
the extended de-stemmer.
At the inlet conveyor belt placed below the hopper, it was observed that over a
period of time some amount of debris was accumulated below the conveyor belt
because the base of the conveyor belt was not solid and it had small openings for the
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debris to pass through it and thus some amount of debris were getting collected at the
bottom of the inlet conveyor belt over a period of time as shown in Figure 5-7.
Figure 5-7. Debris collected below the feeding conveyor belt over a period of time.
The debris was eliminated by the debri removal conveyor belt and de-trasher. It
was noticed that majority of big twigs were taken care by the debri removal conveyor
belt as shown in the Figure 5-8.
Figure 5-8. Big twigs and debris eliminated by the debri removal conveyor belt.
61
The big twigs were collected along with other debris in a box and their masss
were noted down. The weighing of debris was repeated for all six observations as
shown in the table 5-8.
Table 5-7. Mass of debris removed by debri removal conveyor belt for regular and extended de-stemmer truck load
Observations Mass of Debris Removed by Conveyor
Regular De-Stemmer Load (Kgs)
Mass of Debris Removed by Conveyor
Extended De-Stemmer Load (Kgs)
1 0.22 0.62 2 0 0.36 3 0.84 0.2 4 0.38 0.44 5 0.74 0.28 6 1.88 1.16
Total Debris 4.06 3.06
It was observed that 32.23 percent of debris from the total mass of the debris
from the overall load of fruit and debris of citrus fruits was eliminated by the debri
removal conveyor belt. The main advantage of this debri removal conveyor belt was
efficient elimination of big twigs from the load of fruit and debris.
It was also observed that the majority of the debris was eliminated by the de-
trasher as shown in the Figure 5-9.
62
Figure 5-9. Debris eliminated by the de-trasher.
As the fruits and debris pass through the de-trasher, the debris was pulled down
efficiently and the debris were collected in a box, measured on the weighing scale and a
clean load of fruits was collected in the goat truck.
Table 5-8. Mass of debris removed by de-trasher for regular and extended de-stemmer truck load
Observations
Mass of Debris Removed by De-trasher
Regular De-Stemmer Load (Kgs)
Mass of Debris Removed by De-trasher
Extended De-Stemmer Load (Kgs)
1 0.42 1.8 2 0.66 2.68 3 0.98 0.18 4 1.34 0.78 5 1.76 0.9 6 1.98 1.44
Total Debris 7.14 7.78
The overall efficiency of the de-trasher from the regular de-stemmer load was
nearly 69.84% of the total debris was eliminated where as for extended de-stemmer
load 67.58% of the total debris was removed efficiently by the de-trasher. The efficiency
of de-trasher for different observations is mentioned in the table below.
63
Table 5-9. Overall efficiency of the de-trasher
Observations
Overall Efficiency Of The De-Trasher for
Regular De-Stemmer Load (Kgs)
Overall Efficiency Of The De-Trasher for
Extended De-Stemmer Load (Kgs)
1 0.65 0.74 2 1 0.88 3 0.53 0.47 4 0.77 0.63 5 0.70 0.76 6 0.51 0.55
Average Debris Eliminated by the De-trasher for Different
Truck Loads 0.69 0.67
Discussion
The problems faced during the experiment were the debris getting trapped on the
edges and reduced the performance of the extended de-stemmer. The debris reduced
the life and debri removal efficiency of the de-stemmer. Big twigs created a problem in
operation of de-stemmer by getting trapped in between two rollers and cease the
rotation of de-stemmer which indirectly reduced the debri removal efficiency.
Illumination of light was another problem faced while the machine vision system was
used to estimate the mass of debris. The problem was the varying sunlight intensity
over time, which prevented from acquiring high quality images because the illumination
inside the box is heavily affected by the intensity of the sunlight due to the opening
underneath the camera box along with the initial camera setting. The quality of images
obtained was low which created problems in finding the pixel area.
Initially, the main problem was caused by the big branches, which were caught
by the de-stemmer and the rollers were not able to spin and eliminate the debris. Long
branches were caught in between two adjacent spinners, which were rotating in the
64
opposite direction and were not able to separate the debris effectively. Figure 5-10
gives an example about the problem.
Figure 5-10. Debris caught in-between adjacent spinners.
Apart from the big branches, short petioles were another problem faced during
the experiment. These petioles were not completely removed by the de-stemmer and
only the half portion of the petioles was removed from the citrus fruits. Petioles less than
0.05 meters were difficult to remove, since they were not able to get in contact with the
spinners and were not removed completely. Figure 5-11 indicates the short petiole that
was difficult to remove.
Figure 5-11. Petiole less than 0.05 meters which was difficult to extract.
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The main challenge is to incorporate the modified catch frame de-stemmer onto
a mechanical harvester and test it during actual harvesting. Another challenge is to
design a conveyor belt system for moving the removed debris by the de-stemmer. The
conveyor belt should be placed underneath the de-stemmer for moving the debris which
is removed by the de-stemmer when the fruit are harvested.
New Ideas for Future Modification
Modification of the mechanical harvester was a challenging task because of lack
of space for modifications and also the harvester was out of hydraulic power. Different
ideas and their estimated costs were analyzed. The designs were discussed with
engineers in Oxbo, International Corporation who is the manufacturer of the mechanical
harvester. These engineers gave their comments on each individual design, and based
on its feasibility, they came up with approximate cost estimation.
Figure 5-12. Two roller brushes installed on the conveyor belt rotating in the opposite direction for eliminating debris.
Idea-1 is represented in Figure 5-12. This idea consists of two brushes which are
installed on the conveyor belt as shown in Figure 5-13, and are rotating the opposite
direction of each other.
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Figure 5-13. Conveyor belt installed on mechanical harvester.
This system can be implemented on the conveyor belt which is before the camera box
is placed on the mechanical harvester. The top brush is rotating in clockwise direction
and the brush next to it is rotating in the counter-clockwise direction. As the fruits are
moving to the right side as shown by the arrow in the Figure, the brushes will throw the
debris by rotating the brushes. The modification cost for this idea was estimated around
$4,500 by the Oxbo engineers. The brushes cost about $1,000 each along with
bearings, motors and labor around $2,500 approximately.
Idea-2 is represented below in Figure 5-14. This idea is the simplest one which does not
incur any modification cost. This design consists of removing the solid base below the
conveyor belt so that the debris moving with citrus fruits fall off due to gravity and
vibration of the conveyor belt. The Oxbo engineers mentioned that removing of the solid
base would lead to instability in the structure of the mechanical harvester.
67
Figure 5-14. Conveyor belt with no solid metal base.
Idea-3 is represented in Figure 5-15. This idea consists of three brushes which are
rotating the opposite direction as shown in the Figure. The brushes which are attached
to the conveyor belt are moving in clockwise direction opposite to that of the conveyor
belt and not allowing debris to pass through it. This would increase the debri removal
efficiency of the mechanical harvester. The modification cost for this idea was estimated
around $7,000 by the Oxbo engineers. The brushes cost around $1,000 each along with
bearings, motors and labor around $4,000 approximately.
Figure 5-15. Conveyor belt with three sets of brushes rotating in the opposite direction of the conveyor belt.
Idea-4 is represented in Figure 5-16. The idea consists of providing a series of de-
stemmer on the conveyor belt which is placed right below the catch frame of the
mechanical harvester. This conveyor is located on flat surface of the mechanical
harvester and the more amount of debris can be eliminated by using this system. As
shown in the Figure the de-stemmer can be placed in different positions so that debris
68
can be eliminated completely at initial phase. This idea was estimated about $20,000
approximately by the Oxbo engineers depending on the mass and drives of the system.
Figure 5-16. De-stemmer installed on the conveyor belt which is below the catch frame.
Idea-5 is represented in Figure 5-17. This idea is similar to the modification of the
catch frame. De-stemmers are attached on the catch frame such that the debris directly
comes in contact with de-stemmer and gets eliminated at the initial level of debri
elimination process of the mechanical harvester. This idea was estimated approximately
$50,000 to $150,000 depending on the length and type of de-stemmers used.
Figure 5-17. De-stemmer installed on the catch frame for removal of debris.
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CHAPTER 6 CONCLUSION
This thesis describes and detection of debris using machine vision and
elimination using an extended de-stemmer for a continuous citrus canopy shake and
catch harvester. The hardware setup and software have been described. A t-test was
performed to compare the efficiency of regular and extended de-stemmer and states
that the extended de-stemmer was more efficient in eliminating debris compared to
regular de-stemmer which are currently used by continuous canopy shake and catch
harvesters. The efficiency of the de-stemmers was also compared by the percentage of
debris removed by the spinner from the total amount of input fruit-debri samples and
only debris. The percentage of debris removed by extended de-stemmer was more
compared to regular de-stemmer.
The R2 value for debri mass estimation from the experimental images was 0.84
between the predicted actual mass with pixel area in the images. This system can be
implemented to quantify the amount of debris. Detection of debris using machine vision
at the citrus grove can be beneficial in cost reduction for the processing plant and also
lead to environmental safety.
The results obtained from the experiment indicated that the efficiency of debri
removal by the catch frame de-stemmer was very high. The efficiency of de-stemmer for
petiole removal was 50% for petioles less than 0.05 meters and 86% for petioles more
than 0.05 meters. The efficiency of the catch frame de-stemmer was 99.86% of the total
debris and fruit samples input. The amount of debris removed by the modified catch
frame de-stemmer was very high and this system can be implemented on the harvester
to increase the efficiency of debri removal.
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One full load of harvested fruit and debris from a goat truck was tested for each
of the regular and extended de-stemmers. It was observed that 0.21% of debris from
the total mass of fruit and debris was received from the first load of regular de-stemmer
compared to 0.18% of debris from the total mass of fruit and debris was received from
the first load of extended de-stemmer. For the second load, it was observed that 0.30%
of debris from the total mass of fruit and debris was received from the regular de-
stemmer load compared to 0.16% of debris from the total mass of fruit and debris from
the extended de-stemmer. Since only one full load of harvested fruit and debris was
tested for each testing of the regular and extended de-stemmers, the percentage
difference was not much for this trial. However, over an entire harvesting season, much
more debris will be removed by the extended de-stemmer. Therefore, the extended de-
stemmer will be more efficient in eliminating debris than the regular de-stemmer.
The load of fruit and debris were fed on the de-trasher to filter out more amount
of debri sample from the mechanically harvested citrus fruits. It was observed that
32.23% of debris from the total mass of the debris from the overall load of fruit and
debris of citrus fruits was eliminated by the debri removal conveyor belt. It was also
observed that the overall efficiency of the de-trasher from the regular de-stemmer load
was nearly 69.84% of the total debris was eliminated where as for extended de-
stemmer load 67.58% of the total debris was removed efficiently by the de-trasher.
Overall for all the six observations an average of 68.71% of debris was eliminated by
the de-trasher from the mechanically harvested citrus fruits from the regular and
extended de-stemmer load and a clean load was obtained. Some of the big twigs were
also removed by the debri removal conveyor belt which is placed at the end of the
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feeding conveyor belt of the de-trasher. Thus the use of de-trasher is more efficient in
removal of debris and sending a clean load of citrus fruit to the processing plant.
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APPENDIX ACTUAL MASS OF DEBRIS FOR REGULAR AND EXTENDED DE-STEMMER
Regular De-Stemmer Mass are in (Kg)
One Basket REP 1 REP 2 REP 3 Total Mass of Basket 13.41 9.69 10.60 Mass of Fruits after Experiment 10.87 8.15 8.88 Total Mass of Debris 2.54 1.54 1.72 Mass of Debris from De-Stemmer 0.58 0.67 0.68 Actual Mass of Debris from De-Stemmer 0.06 0.14 0.16
Two Basket REP 1 REP 2 REP 3 Total Mass of Basket 29.45 29.90 30.44 Mass of Fruits after Experiment 24.55 24.82 24.82 Total Mass of Debris 4.89 5.07 5.62 Mass of Debris from De-Stemmer 0.68 0.78 0.72 Actual Mass of Debris from De-Stemmer 0.15 0.26 0.20
Three Baskets REP 1 REP 2 REP 3 Total Mass of Basket 34.70 35.52 31.80 Mass of Fruits after Experiment 28.72 28.54 25.28 Total Mass of Debris 5.98 6.98 6.52 Mass of Debris from De-Stemmer 1.00 0.95 0.84 Actual Mass of Debris from De-Stemmer 0.48 0.43 0.32
Four Baskets REP 1 REP 2 REP 3 Total Mass of Basket 40.68 40.59 40.41 Mass of Fruits after Experiment 34.07 33.34 33.98 Total Mass of Debris 6.61 7.25 6.43 Mass of Debris from De-Stemmer 0.67 0.96 0.66 Actual Mass of Debris from De-Stemmer 0.14 0.44 0.14
Debris mass - 0.61
Mass of Box
73
Extended De-Stemmer Mass are in (Kg)
One Basket REP 1 REP 2 REP 3 Total Mass of Basket 12.32 10.92 11.60
Mass of Fruits after Experiment 10.87 8.61 9.88 Total Mass of Debris 1.45 2.31 1.72
Mass of Debris from De-Stemmer 0.74 0.63 0.56 Actual Mass of Debris from De-Stemmer 0.22 0.11 0.04
Two Basket REP 1 REP 2 REP 3 Total Mass of Basket 25.82 21.74 26.36
Mass of Fruits after Experiment 21.65 17.12 23.01 Total Mass of Debris 4.17 4.62 3.35
Mass of Debris from De-Stemmer 0.78 0.74 0.78 Actual Mass of Debris from De-Stemmer 0.26 0.22 0.26
Three Basket REP 1 REP 2 REP 3 Total Mass of Basket 36.51 36.60 34.88
Mass of Fruits after Experiment 29.99 29.54 28.90 Total Mass of Debris 6.52 7.07 5.98
Mass of Debris from De-Stemmer 0.62 0.46 0.59 Actual Mass of Debris from De-Stemmer 0.62 0.46 0.59
Four Basket REP 1 REP 2 REP 3 Total Mass of Basket 40.32 39.23 38.69
Mass of Fruits after Experiment 33.52 32.71 32.98 Total Mass of Debris 6.80 6.52 5.71
Mass of Debris from De-Stemmer 0.59 0.26 0.47 Actual Mass of Debris from De-Stemmer 0.59 0.26 0.47
74
With Regular De-Stemmer
Observations
Total Mass of Debris (Kg)
Actual Mass of Debris from De-
Stemmer (Kg) REP1 2.72 0.06
One Basket REP2 1.72 0.14 REP3 1.90 0.16 REP1 5.07 0.15
Two Basket REP2 5.25 0.26 REP3 5.80 0.20 REP1 6.16 0.48
Three Basket REP2 7.16 0.43 REP3 6.70 0.32 REP1 6.80 0.14
Four Basket REP2 7.43 0.44 REP3 6.61 0.14
Difference Between Total Mass
to Actual Mass of Debris (Kg)
% Amount of Debris not Removed by the Regular
De-Stemmer
% Amount of Debris removed
by Regular De-Stemmer
2.66 97.75 2.25 1.58 91.63 8.37 1.74 91.71 8.29 4.92 96.95 3.05 4.99 95.05 4.95 5.60 96.52 3.48 5.68 92.21 7.79 6.72 93.96 6.04 6.38 95.19 4.81 6.65 97.87 2.13 6.99 94.12 5.88 6.48 97.92 2.08
75
With Extended Spinners
De-Stemmer
Observations
Total Mass of Debris (Kg)
Actual Mass of Debris from De-
Stemmer (Kg) REP1 1.63 0.22
One Basket REP2 2.49 0.11 REP3 1.90 0.04 REP1 4.35 0.26
Two Basket REP2 4.80 0.22 REP3 3.53 0.26 REP1 6.70 0.62
Three Basket REP2 7.25 0.46 REP3 6.16 0.59 REP1 6.98 0.59
Four Basket REP2 6.70 0.26 REP3 5.89 0.47
Difference Between Total Mass
to Actual Mass of Debris (Kg)
% Amount of Debris not Removed by the Extended
De-Stemmer
% Amount of Debris removed by Regular De-
Stemmer 1.41 86.64 13.36 2.38 95.71 4.29 1.87 98.05 1.95 4.09 93.96 6.04 4.59 95.50 4.50 3.28 92.69 7.31 6.09 90.79 9.21 6.79 93.69 6.31 5.57 90.44 9.56 6.39 91.56 8.44 6.44 96.10 3.90 5.41 91.95 8.05
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LIST OF REFERENCES
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Chinchuluun, R., W. S. Lee, and R. Ehsani. 2007. Citrus yield mapping system on a canopy shake and catch harvester. ASABE Paper No. 073050. St. Joseph, Mich.: ASABE.
Chinchuluun, R., W. S. Lee, and R. Ehsani. 2009. Machine vision system for determining citrus count and size on a citrus canopy shake and catch harvester. Applied Engineering in Agriculture 25(4): 451-458.
Dewdney, M.M., and J.H. Graham. 2009. Florida citrus pest management guide: citrus canker. EDIS. UF/IFAS. FL.
Futch, S. H., and F.M. Roka. 2005. Continuous canopy shake mechanical harvesting systems. EDIS. UF/IFAS. FL.
Futch, S.H., J. D. Whitney, J. K. Burns, and F.M. Roka. 2005. Harvesting: From manual to mechanical. EDIS. UF/IFAS. FL.
IFAS. 2010. Citrus Mechanical Harvesting: 2009-2010. University of Florida. Gainesville, Florida. IFAS Citrus Mechanical Harvesting. Available at: http://citrusmh.ifas.ufl.edu/index.asp. Accessed 26 January 2009.
Lee, W.S., R. Ehsani, and R.Shankar. 2008. Trash detection system for a citrus canopy shake and catch harvester using machine vision. ASABE Paper No. 084249. St. Joseph, Mich.: ASABE.
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OXBO. 2010. Mechanical Harvesters: 2009-2010. Oxbo International Corporation. Available at: http://www.oxbocorp.com/. Accessed 26 January 2008.
Patil, R., W. S. Lee, R. Shankar, and R. Ehsani. 2009. Detection and elimination of trash using machine vision and extended de-stemmer for a citrus canopy shake and catch harvester. ASABE Paper No. FL09-129. St. Joseph, Mich.: ASABE
Pik Rite. 2010. Mechanical Harvesters: 2009-2010. Pik Rite Corporation. Available at: http://www.pikrite.com/. Accessed 26 June 2010.
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Roka, F.M., Burns, J.K., Syvertsen, J., Spann, T., Hyman, 2009. Improving the economic viability of Florida citrus by enhancing mechanical harvesting with the abscission agent CMNP, UF/IFAS, FL.
Spann, T.M. 2007. Mechanical harvesting system and CMNP effects on debris accumulation in loads of citrus fruits. EDIS. UF/IFAS. FL.
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BIOGRAPHICAL SKETCH
Rohan graduated with a dual master degree in industrial systems engineering and
agriculture and biological engineering (2010) and was working as a Graduate Research
Assistant at University of Florida. His current research is on detection and elimination of
debris using machine vision and extended de-stemmer and designing new ideas for a
citrus canopy shake and catch mechanical harvester.
Rohan received his bachelor’s degree in mechanical engineering (2007) from
Visvesvaraya Technological University, India. In 2007, Rohan joined the mining industry
as a maintenance engineer and manager for a short period of 8 months. The company
use to excavate iron-ore from mining fields and separate different sizes of ore particles.
His job designation was to manage personnel for smooth operation of the plant and also
as a Maintenance Engineer to schedule proper maintenance for machineries used on
the plant.
In 2003, Rohan had a good amount of experience in different fields like finance
and mining industry. Rohan started his professional carrier with J.V.S & Stock Broker
Pvt. Ltd Mumbai, India as a stock broker for more than 7 years along with his
undergraduate studies handling more than 200 clients. He served the firm as a financial
advisor helping clients in their investments by purchasing and selling of shares. He is
also experienced in equity market, derivatives, futures and options, commodity markets,
currency exchange and filing tax returns. Presented various seminars and conducted
stock market simulation programs during his undergraduate curriculum.
