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Quiz 1 What is the most likely game played at each of these stadiums? 1. _________________ 2. _________________ 3. _________________ 4. _________________ 5. _________________ 1 2 3 4 5
Quiz 1What is the most likely game played at each of these stadiums?
1. _________________
2. _________________
3. _________________
4. _________________
5. _________________
1
2
3
4
5
Quiz 1What is the most likely game played at each of these stadiums?
1. Football
2. Maybe field hockey, but more likely hand ball
3. Soccer
4. Cricket
5. Baseball
1
2
3
4
5
Hyperspatial Remote Sensing
• Introduce the electromagnetic spectrum• Spectral reflectance• Spectral signature
• Resolution – Spectral, Spatial, Radiometric• Digital imagery. What is a pixel?
• Types of imagery?• Aerial • Satellite• LiDAR (Talk about later in the quarter)
• Where to get imagery?• Different sites to check out
1940’s airphoto 2003 NIR airphoto2000, High res. Satellite
Riparian Forest
Upland Savanna
Prairie
Limestone Glade
Bottomland Forest
Residential
Commercial
Oak Hickory Forest
Pasture
Upland Scrub
Upland Woodland
Road
Prairie Savanna
What causes the differences of colors on an image of the same landscape?
The electromagnetic spectrum
micronsangstroms cm m
TV, radio
Radar
Microwaves
Infrared
Ult
rav
iole
t
X-rays(soft)
X-rays(hard)
Gammarays
EHF SHF UHF VHF HF LF
Microns (micrometres)
ApproximateWavelength
0.01 0.1 1 10 100 0.1 10 100 0.1 1 10 1 10 100
0.3 0.4 0.5 0.70.6 0.8 0.9 1.0
Visible Light
0.4
0
0.4
3
0.4
9
0.5
3
0.5
8
0. 6
3
0.7
0
Nearinfrared
Ora
ng
e
Ye
llo
w
Gre
en
Blu
e
Vio
let
Nearultraviolet R
ed
Reflection
• We are most interested in measuring the diffuse reflectance properties of earth features
• The reflectance characteristics of an earth feature may be quantified by measuring the portion of incident energy that is reflected
• It is useful to think of the Principle of conservation of energy relationship expressed as:
• AKA The RAT Law . All energy is either reflected, absorbed, or transmitted.
ER = EI – (EA + ET)
EI ER
ET
EA
Target (leaf) interaction
TRANSMITTANC
E
Vegetation - panchromatic
Vegetation - color
Vegetation – color infrared
Reflection
Most earth surface features lie somewhere between perfectly specular or perfectly diffuse reflectors (depending) on the surface roughness of the feature in comparison to the wavelength of the incoming radiation
Bidirectional Reflectance Distribution Function (BRDF) is used to describes the reflection characteristics of a surface
Vegetation is a near- perfect Lambertian (diffused) surface
Roads are a near- perfect Fresnel (specular) surface
Reflectance
Many vegetation types can be distinguished just by looking at their spectral curves
Landsat ETM true color composite (bands 1, 2, 3)
Landsat ETM false color composite (bands 1, 2, 4) Ikonos
Absorption by atmospheric gases
Atmospheric windows
(Robinson and others 1995)
Land
sat ETM b
and
1Lan
dsat ETM
ban
d 2
Land
sat ETM b
and
3Lan
dsat ETM
ban
d 4
Land
sat ETM b
and
5
Land
sat ETM b
and
7
Land
sat ETM b
and
6 –
The
rmal In
frared
The visible portion of the spectrum, corresponds to both an atmospheric window and the peak energy level of the sun
Resolution
• Spatial resolution – Scale at which an object can be resolved.
• Spectral resolution – How many places along the electromagnetic spectrum are we measuring. True color image = 3 (red, green, blue), Landsat = 7 bands
• Radiometric resolution - The ability to detect very slight differences in energy
• Temporal – Time increments at which data is collected.
Radiometric resolution
0 = 00000000
1 = 00000001
2 = 00000010
3 = 00000011
…
254 = 11111110
255 = 11111111
0 = 0000000000000000
1 = 0000000000000001
2 = 0000000000000010
3 = 0000000000000011
…
65534 = 1111111111111110
65535 = 1111111111111111
8-bit 16-bit
Most satellite and aerial imagery is provided in the 8-bit format with values ranging form 0 -255
2-bit versus 8-bit
Digital image
• All digital numbers can be assigned to gray levels or color values for the purpose of display
255
0
1910
28
21
3
16255
RGB Images – White Pixel
255
255
2558 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Displayed Color
Image Channel
RGB Images – Black Pixel
0
0
08 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images –
127
127
1278 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images – Dark Grey Pixel
35
35
358 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images – Red Pixel
0
0
2558 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images – Green Pixel
255
0
08 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images – Blue Pixel
0
255
08 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images – Cyan Pixel
255
255
08 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images – Brown Pixel
125
35
2008 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
RGB Images – Light Yellow Pixel
255
150
2558 bit Channel
8 bit Channel
8 bit Channel
Red Gun
Green Gun
Blue Gun
Image Channel
Displayed Color
History of Remote Sensing
Photography is Invented
1839
• Beginning of practice of photography by Louis Daguerre (France)
• One of the most famous of several people who invented photography Nicéphore Niépce
• He regularly used a camera obscura as an aid to painting in perspective, and this had led him to seek to freeze the image
In 1826, French scientist Joseph Nicéphore Niépce, took that photograph, titled View from the Window at Le Gras at his family’s country home.
The First Aerial Photographer
1859
• Gaspard Felix Tournachon, also known as Nadar, was a famous French photographer and balloonist who carried his bulky cameras aloft.
• His goal was to make land surveys from aerial photographs. Although Nadar set the stage for the future of remote sensing as we know it, he was not a success at aerial surveying.
• His photographic observations did, however, catch the attention of the military.
Nadar used this humorous card to promote his services.
The US Army Balloon Corps
1862
• In April 1861 Professor Thaddeus Lowe went up in a balloon near Cincinnati, Ohio, to make a weather observation. Unfortunately, strong winds carried him all the way to South Carolina, where he was arrested as a Union spy.
• Eventually released, he believed that tethered balloons could be useful for reconnaissance. After viewing a demonstration, President Lincoln agreed and authorized the US Army Balloon Corps, with Lowe in charge.
Despite its advantage to the North during the American Civil War, the unit was deactivated in 1863. Balloons had a not-surprising tendency to draw enemy fire.
Photography from Kites
1882 – becomes popular
THEN NOW
The Bavarian Pigeon Corps
1903
• An innovative attempt to avoid dangerous balloons or uncertain kites was to attach a very light camera to a carrier pigeon.
• These cameras took a picture every thirty seconds as the pigeon winged its way along a straight course to its home shelter.
• Releasing the birds behind enemy lines presented no small problem.
Dresden International Photographic Exhibition; picture postcards of the fair taken by pigeons were very popular
Photos from an Aeroplane
1909
• Wilbur Wright was the pilot for two notable events.
• The first photographs from an aircraft were taken by Wilbur's passenger, L. P. Bonvillain, on a demonstration flight in France in 1908.
• The next year, the first aerial motion pictures were taken in Italy when another photographer accompanied Wright.
Wright brothers fly first motorized plane
The Great War
1914 - 1918
• The biplane replaced the balloon for observing enemy positions in the trench warfare of World War I.
• By the end of the war, the value of complete photographic reconnaissance was recognized by both sides: the Germans acquired 4,000 photos a day as part of the planning for their last great offensive of 1918, and the US Army made over one million prints in the last four months of the war.
(left) Military aerial observer/photographer during World War I(right) Vertical aerial photograph of trenches in 1916
World War II
1944
• Aerial photo acquisition and intelligence gathering was common practice
• 90% of aerial photo analysts were women
Apollo Program
1968
• The mission to the Moon needed maps of the lunar surface, especially of the proposed landing sites. These were prepared using remote sensing techniques. Apollo 8 returned the first pictures of the Earth from deep space (1968). Images from the Apollo 9 multispectral four-lens camera were digitized and used to develop techniques for processing Landsat data, which, in 1969, was still four years away.
Grad Students: AB suggested reading summarizes the last 50 years of satellite remote sensing
But what about aerial photography now?
1970 - present
• Still going strong, especially in the government and environmental management sectors
• Color and near infrared
• Digital format (soft copy), computerized acquisitions and processing
Source: http://www.appliedairborne.com/drones
UAV’s, Drones, Quadcopters, Model Aircrafts, Balloons and Kites
Don’t try this on your own yet!
Camera locations and image overlap (only upper photos)
Dense cloud (only upper photos)
Wireframe (only upper photos)
Dense cloud (only upper photos)
Wireframe (only upper photos)
Digital Elevation Model (only upper photos)
Orthophotograph (only upper photos)
DSM & 10 cm contour (only upper photos)
Where to get Imagery
Start with Google Earth UW map library or other Universities – (e.g. WAGDA) Check Geoeye or Digital Globe
USDA NAIP program USGS – GLOVIS (especially good for Landsat) State or city gov., (City of Seattle, City of Tacoma), Cedar River Watershed NASA NOAA SCGIS listserve UW GIS listserve State (DNR) Federal agencies (USDA FS, NPS, BLM, Army Corps of Engineers)
Check with partners or consortia (Puget Sound LiDAR Consortium) Call people up
Fly your own … ‘soonish’ (FAA regulations due in 2017)
Remote Sensing Erasdata processing and analysis – production of information
1830s Visual interpretation
1920’sOptical analytical devices
1970sComputer aideddigital analyses
2010sCrowd sourcing
Remote Sensing Erasdelivery of information to the end user
1830sPhotographic productsHand-drawn products
1970sComputergenerated productsvia digital tapes 1990s 2000s
via the internetwired wireless
2010scloud storage/computing
Remote Sensing Erasdata recording and storage
1830sFilmBW/Color/Color IR
1960s/70sDigitalMagnetic tape 1990s
MechanicalHard DrivesCD/DVD
2000sNon-MechanicalHard Drives
2010sCloud Storage
Lectures & Labs Objectives
Today• Theory,
background & terminology
• Examples
Wednesday• Future trends in
remote sensing
• Examples
CONCEPTS Role of remote sensing in monitoring & measuring natural resource systems The concepts of spatial, spectral & temporal resolution provided by the different
remote sensing systems Satellite imagery, their uses and limitations Recent high-tech imaging, their potentials and limitations Conventional aerial photos, their uses and limitations
LABS Simple exercises to
demonstrate the differences in aerial vs. satellite imagery
Simple exercises to demonstrate the differences in active vs. passive sensors
Simple mensuration techniques (i.e. scale)
RESOLUTION
Data Source:• AVIRIS, Hyperion
Applications: • Vegetation Health• Species Identification• Invasive Species …
Tools:• Spectral Analysis
Data Source:• MODIS, AVHRR
Applications: • Change analysis• Monitoring…
Tools:• Harmonic Analysis
Data Source:• LiDAR• Aerial Photos, IKONOS
Applications: • Forest Structure …
Tools:• Feature Extraction
Remote Sensing Tools
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DATASET Spatial Res. (Pixel size) Spectral Res. Temporal Example
Aerial ImageryHIGH(1 m)
LOW (3 bands)
MEDIUM(1 – 3 years)
LandsatSatellite Imagery
MEDIUM (30 m)
MEDIUM(7 bands)
HIGH(every 16 days)
LiDARVERY HIGH
(4-6 pts / m2)VERY LOW(1 band)
LOW(rare)
