CONNECT THE DOTSIntroduction to Computational and Biological VisionKeren shemesh
INTRODUCTION The game
educative and creational Motivation & Goal
Kids often play the game alone. Errors causing false understanding of the
numerical system. Kids can check themselves.
Known topics in computer vision: OCR Hough and Circular Hough transform
ASSUMPTIONS Dot Circles
circle-shaped in range of 5 to 15 approximately the same size and shape filled black
All numbers same font size All digits
can easily be isolated and extracted horizontal
the intensity of the components is clearly different from the intensity of the background
PRINCIPLES OF THE ALGORITHM: STAGE 1 finds all connected dots in the image
Finding all circles using Circular Hough Transform Creating bounding box Filter circles
Ratio of white-pixels/pixels in the bounding box < threshold
The center of the circle is black
PRINCIPLES OF THE ALGORITHM: STAGE 1
PRINCIPLES OF THE ALGORITHM: STAGE 2 finding all numbers in the image
Extracting all connected components
PRINCIPLES OF THE ALGORITHM: STAGE 2 filtering out the potential connected dots
while assuming that a connected dot is not ‘in’ a number And vice versa
PRINCIPLES OF THE ALGORITHM: STAGE 2 filtering out components not on the average
height filtering out components not on the average
width
PRINCIPLES OF THE ALGORITHM: STAGE 2 Link all digit in the same number
PRINCIPLES OF THE ALGORITHM: STAGE 3 Interpreting each digit using OCR detection
pre-saved database of font templates for every number 0-9
the best fit correspondence between a component and the database is calculated using correlation
PRINCIPLES OF THE ALGORITHM: STAGE 3
PRINCIPLES OF THE ALGORITHM: STAGE 4 matching the dot circles with the numbers by
proximity Match the closest digit of every number to every
dot circle Only the closest circle is matched to each
number - removing spare circles All linked digits are calculated to a number All connected dots with matched numbers are
sorted by the numbers
PRINCIPLES OF THE ALGORITHM: STAGE 4
PRINCIPLES OF THE ALGORITHM: STAGE 5 + 6 Drawing lines between connected dots with
sequential numbers using interpolation Filing the image with random numbers
RESULTS
KNOWN ISSUES False identification of number False identification of connected dot Inaccurate OCR detection due to an unknown
font False identification of connected dot and a
number
DISCUSSION AND CONCLUSIONS Correct identification depends on the
components in the image Size Proximity to others Font of the numbers
THE APPLICATION
QUESTIONS?