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Remote Sensing Image Acquisition

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Remote Sensing Image Acquisition Supplement to Lecture 1 material prepared by R. Lathrop 9/99 updated 8/03 includes s previously prepared by S. Madry and C. Colvard – PowerPoint PPT presentation

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Title: Remote Sensing Image Acquisition


1
Remote Sensing Image Acquisition
  • Supplement to Lecture 1
  • material prepared by R. Lathrop 9/99
  • updated 8/03
  • includes slides previously prepared by S. Madry
    and C. Colvard
  • Readings
  • ERDAS Field Guide 5th Ed. Ch 1, 356-82

2
Digital Image Acquisition
  • Digitization of analog aerial photography, can be
    very useful for historical studies and/or for
    high spatial resolution needs
  • Direct acquisition using some form of digital
    imaging sensor

3
Early attempts
  • Kite system acquired aerial photos of the great
    San Francisco earthquake and fire
  • Pigeon cameras
  • The development of aircraft
  • World Wars I and II

4
Aerial Cameras
Keystones Wild RC-10 mapping camera
A large format oblique camera
5
Aerial photos
  • Black White - single panchromatic layer
  • Color 3 layers B-G-R
  • Color IR 3 layers G-R-NIR

6
USGS Aerial Photo Products
Aerial Products Description National Aerial
Photography Program (NAPP)
Recent,high-quality aerial photos
covering the conterminous U.S. on five- to
seven-year cycles (1987 - present). National High
Altitude Photography (NHAP)
High-altitude aerial photos
for the conterminous U.S. (1980 - 1989). Digital
Orthophoto Quadrangles (DOQs)  Digital images of
aerial photos which combine the image
characteristics of the photo with the
georeferenced qualities of a map (1987 -
present). Space Acquired Photography  Photos
taken from the International Space Station (ISS),
Shuttle, Skylab, Gemini, and Apollo missions
(1965 - present). For more info
http//edc.usgs.gov/products/aerial.html
7
Analog Image Digitization
  • Scanning micro-densitometer
  • Linear array charge-coupled device
    e.g., flat-bed scanners
  • Area array charge-coupled device
    e.g., digital camera

8
Remote Sensing Systems - Instrumentation
  • Radiometer - electro-optical instrument measuring
    radiant flux (energy)
  • Spectroradiometer - instrument that measures
    radiant flux as a function of wavelength - often
    as a continuous spectra
  • Multispectral scanner - imaging
    spectro-radiometer measuring radiant flux in
    specific spectral wavebands

9
Major Elements of electro-optical scanners
  • Optical system lenses, mirrors, apertures,
    modulators dispersion devices
  • Detectors provide an electrical signal
    proportional to the irradiance on its active
    surface, generally some type of semiconductors
  • Signal Processor performing specified functions
    on the electrical signal to provide the desired
    output data

10
Electro-optical scanners
  • Elements sensitive to electro magnetic energy
    (EME) of certain wavelengths focus energy onto a
    sensor plane. A prism is used to divide the
    energy into specific wavelengths. The CCDs are
    stimulated and produce an electrical signal equal
    to the energy focused upon it. These data are
    recorded.
  • Data are converted from an analog electrical
    signal to a digital number

11
3 different scanner designs
Single detector CCD-Scan Mirror TM
Pushbroom scanner SPOT
Two dimensional Staring Array Space Imaging
Original Current
Future
12
Important imaging parameters
  • The Instantaneous Field of View (IFOV) subtends
    an area on the terrain called a Ground Resolution
    Cell (GRC)
  • The Angular Field of View determines the width of
    the Ground Swath
  • The Dwell Time, the time required for the
    detector IFOV to sweep across the GRC

13
Airborne Remote Sensing
Aircraft Scanners Digital imagery acquired
from several multispectral scanners on board NASA
ER-2, NASA C-130B, and NASA Learjet aircrafts
(1982 - 1995). For more info http//edcdaac.usgs.
gov/airborne/air_scan.html Digital Cameras
increasingly aerial imagery is being acquired
through digital camera framing systems that can
collect multispectral (VIS-NIR) imagery and be
quickly corrected through GPS-based navigational
systems to produce digital orthophotographic
imagery in near-real time
14
Remote Sensing Satellites in Space How do they
get there?
http//visibleearth.nasa.gov/cgi-bin/viewrecord?49
2
15
MODIS Terra Launches
http//visibleearth.nasa.gov/cgi-bin/viewrecord?13
5
16
Types of satellite orbits
  • Geostationary Polar

700-900 km
35,800 km
17
Polar Orbitting Satellite
http//visibleearth.nasa.gov/cgi-bin/viewrecord?13
4
18
Geostationary vs. polar orbiting sensors
Geostationary sensors orbit with the earth
continually viewing the same hemispheric
area Polar orbiters, continually view new areas
of the earth as the planet rotates underneath the
sensor. Keeps the same general solar time as it
cross the equator on each orbit - called sun
synchronous
Polar orbit
19
Many different systems - which to choose?
20
  • AVHRR-Advanced Very High Resolution Radiometer
  • Polar orbit, coarse spatial resolution 1 and 4
    km cells, broad 2400 km ground swath width
  • 2 operational now-1 day and 1 night pass for each

21
AVHRR
  • Thermal AVHRR provides water temperature data
  • 3 bands in TIR

Gulf Stream
22
Remote Sensing of the Earth Clues to a Living
Planet
  • Scientists at the NASA Goddard Space Flight
    Center have used the AVHRR to create maps of
    vegetation greenness for the entire globe
  • The NASA scientists have combined numbers of
    satellite images to create a composite picture of
    the earth at approximately biweekly intervals
    over a number of years

For more info and images, go to
http//daac.gsfc.nasa.gov/CAMPAIGN_DOCS/BRS_SRVR/a
vhrrbrs_main.html
23
Global AVHRR composite
  • 1 band in the Red .58-.6 um
  • 1 band in the NIR .72-1.1 um
  • Vegetation Index to map vegetation amount and
    productivity

24
Remote Sensing of the Earth Clues to a Living
Planet
  • You can access these images over the INTERNET
  • http//daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/G
    LBDST_Images.html
  • You can either browse through individual images
    or watch an animation
  • First, click on the Global 1 degree 1986 NDVI
    (Climate Data Set) (1.5 MB Quicktime) animation.
    Open it, and click on the gt button. You can go
    more slowly by clicking on the gt button.

25
Remote Sensing of the Earth Clues to a Living
Planet
  • First, click on the Global 1 degree 1986 NDVI
    (Climate Data Set) (1.5 MB Quicktime) animation.
    Open it, and click on the gt button.
  • Watch closely, can you observe the Green Wave in
    the northern hemisphere?
  • What about the Brown Wave?
  • Now look at the southern hemisphere. What do you
    observe?

26
Can you see the Green Wave?
http//daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/G
LBDST_Images.html
27
Remote Sensing of the Earth Clues to a Living
Planet
  • Now take a look at the Northern hemisphere in
    greater detail.
  • Click on the North America 1986 NDVI (750K
    quicktime) Animation.
  • Can you find where you live? How long does it
    stay green?
  • Compare Florida with Maine or Minnesota.

28
North America Close-up
http//daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/G
LBDST_Images.html
29
Remote Sensing of the Earth Clues to a Living
Planet
  • To access more recently acquired AVHRR imagery go
    to the National Oceanographic Atmospheric
    Administration (NOAA) Satellite Active Archive
    http//www.saa.noaa.gov/

30
After a picture-perfect launch into space
December 1999, Terra Began releasing images April
2000. Terra includes MODIS, a 2nd generation
AVHRR-like instrument, with a number of
potential applications in regional to global
scale environmental monitoring of the land, ocean
and atmosphere. Also includes ASTER, CERES, MISR
and MOPITT.
For more info go to http//terra.nasa.gov/
31
MODIS TERRA in Orbit
http//visibleearth.nasa.gov/cgi-bin/viewrecord?13
3
32
  • 36 discrete bands between 0.4 and 14.5 µm
  • spatial resolutions of 250, 500, or 1,000 m at
    nadir.
  • Signal-to-noise ratios are greater than 500 at
    1-km resolution (at a solar zenith angle of 70),
    and absolute irradiance accuracies are lt 5 from
    0.4 to 3 µm (2 relative to the sun) and 1
    percent or better in the thermal infrared (3.7 to
    14.5 µm).
  • MODIS instruments will provide daylight
    reflection and day/night emission spectral
    imaging of any point on the Earth at least every
    2 days, operating continuously.
  • For more info http//eospso.gsfc.nasa.gov/eos_hom
    epage/mission_profiles/instruments/MODIS.php

33
  • 3 visible/NIR(VNIR 0.5 and 0.9 µm) with 15-m
    resolution
  • 3 mid IR (SWIR 1.6 and 2.43 µm) with 30-m res.
  • 5 TIR (8 and 12 µm) with 90-m resolution
  • 60- km swath whose center is pointable
    cross-track 8.55 in the SWIR and TIR, with the
    VNIR pointable out to 24. An additional VNIR
    telescope (aft pointing) covers the wavelength
    range of Channel 3. By combining these data with
    those for Channel 3, stereo views can be created,
    with a base-to-height ratio of 0.6.
  • Overpass every 16 days in all 14 bands and once
    every 5 days in the three VNIR channels. For
    more info http//eospso.gsfc.nasa.gov/eos_homepag
    e/mission_profiles/instruments/ASTER.php

34
Aqua, Latin for water, is a NASA Earth
Science satellite mission named for the large
amount of information that the mission will be
collecting about the Earths water cycle,
including evaporation from the oceans, water
vapor in the atmosphere, clouds, precipitation,
soil moisture, sea ice, land ice, and snow cover
on the land and ice.
Additional variables also being measured by Aqua
include radiative energy fluxes, aerosols,
vegetation cover on the land, phytoplankton and
dissolved organic matter in the oceans, and air,
land, and water temperatures.The AQUA Platform
includes the MODIS, CERES and AMSR_E instruments.
Aqua was formerly named EOS PM, signifying its
afternoon equatorial crossing time. AQUA was
launched May 2002. For more info
http//aqua.nasa.gov/
35
ERTS-1
  • Earth Resources Technology Satellite-1
  • Renamed Landsat Multispectral scanner (MSS)
  • First images in late 1972
  • Was the first civil remote sensing satellite

36
Landsat MSS bands 4 and 5
GREEN
RED
37
Landsat MSS bands 6 and 7
Note water absorbs IR energy-no returnblack
INFRARED 2
INFRARED 1
38
MSS color composite
Manhattan
Rutgers
  • combining bands creates a false color composite
  • redvegetation
  • light blueurban
  • blackwater
  • pinkagriculture

Philadelphia Pine barrens Chesapeake
Bay Delaware River
39
Landsat 4-5 Thematic Mapper (TM)
40
Cross-track scanning system
41
Landsat TM-7 bands-8 bit data
Spectral (where we look) Radiometric (how finely
can we measure the return) 0-63, 0-255, 0-1023
Landsat TM BAND 1 2 3 4 5
7 6
42
Spectral wavebands of Landsat TM
43
Landsat TM each waveband provides different
information about earth surface features
44
Thermal imagery-temperature
Water analysis-nuclear power cooling ponds)
45
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46
Commercialization of Landsat
  • Landsat was commercialized by Pres. Reagan
  • EOSAT formed
  • sales dropped

47
Landsat 7
  • 15 m ETM (enhanced TM) sensor
  • April 1999 launch
  • Oct.92 Land remote sensing policy act
  • a panchromatic band with 15m spatial
    resolution-fully coregistered w/30m
  • on-board, full aperture, 5 absolute radiometric
    calibration
  • a thermal IR channel with 60m spatial resolution
  • for more info go to http//landsat.gsfc.nasa.gov/

48
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49
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50
  • French commercial remote sensing system
  • First launch in 1986
  • 10 and 20 m spatial resolution
  • 60 km swath width
  • Stereo viewing ability
  • Will have 2.5 m in 1999

51
Panchromatic (PAN) sensor 10 m GRC Pan
0.51-.73 um High Resolution Visible (HRV)
sensor 20m GRC G (.5-.59), R (.61-.68), NIR
(.79-.89) Ground Swath Width of 60 km For more
info go to http//www.spotimage.fr/home/home.htm
52
SPOT before launch
53
SPOT ground stations
54
SPOT 41st images taken March 31, 1998
55
Polar Sun synchronous orbit
2 side-by-side HRV sensors
56
SPOT has steerable mirror
57
Stereo imaging
58
Indian Remote Sensing (IRS) satellite
  • IRS-1C launched in December 1995
  • IRS1D launched in September 1997
  • Panchromatic 0.5-0.75 um
  • 5.8 m GRC, 30 km ground swath
  • 22 day repeat cycle with off-nadir pointability

59
Space Imaging IKONOS
  • Panchromatic (045-0.9 um) 1 m
  • Multispectral 4 m Blue (445-516nm),
    Green(506-595nm) Red (632-698nm)
    NIR (757-853nm)
  • 11 km swath width
  • Pointable to 45o for daily viewing
  • For more info go to http//www.spaceimage.com/ind
    ex.htm

60
IKONOS SAMPLE IMAGERY
Multi-spectral 4m GRC
Pan-chromatic 1m GRC
61
Space Imaging IKONOS Imagery Sample Bound Brook
NJ
1 m panchromatic
4 m multi-spectral
62
  • OrbView-3
  • Panchromatic 1 m
  • Multispectral (color) 4 m
  • Pointable anywhere on globe within 3 days
  • Additional hyperspectral sensor
  • For more info go to
    http//www.orbimage.com/index.html

63
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64
Quickbird
  • DigitalGlobe successfully launched its QuickBird
    satellite on the Boeing Delta II launch vehicle
    on October 18, 2001.
  • Panchromatic 0.61-1m
  • Multispectral (color) 2.5-4 m
  • Can increase the resolution system by adjusting
    the orbit in which the satellite is flown. As a
    result, panchromatic resolution increases from 1
    meter to 61 centimeters and multi-spectral
    increases from 4- to 2.5-meter resolution.
  • The satellite will operate in a 450-km 98-degree
    sun-synchronous orbit, with each orbit taking
    93.4 minutes
  • http//www.digitalglobe.com/index.shtml

65

Different sensors and resolutions
sensor spatial
spectral
radiometric temporal -------------------------
--------------------------------------------------
------------------------------------- AVHRR
1.1 and 4 KM 4 or 5 bands 10
bit 12 hours 2400 Km
.58-.68, .725-1.1, 3.55-3.93
(0-1023) (1 day, 1 night)
10.3-11.3, 11.5-12.5
(micrometers) Landsat MSS 80 meters
4 bands 6 bit
16 days 185 Km
.5-.6, .6-.7, .7-.8, .8-1.1
(0-63) Landsat TM 30 meters 7
bands 8 bit 14
days 185 Km .45-.52,
.52-.6, .63-.69, (0-255)
.76-.9, 1.55-1.75,
10.4-12.5, 2.08-2.3 um SPOT P
10 meters 1 band
8 bit 26 days
60 Km .51-.73 um
(0-255) (2 out of 5) SPOT X 20
meters 3 bands 8 bit
26 days 60 Km
.5-.59, .61-.68, .79-.89 um (0-255)
(2 out of 5) IKONOS 1 and 4 meters
1 and 4 bands 10
bit 1-2 days
11 km .45-.9, .44-.51,
.52-.60, (0-1023)
.63-.70, .76-.85
66
Homework 1 Selecting and Ordering Imagery 1.
Enhanced Landsat Thematic Mapper 7 (ETM) imagery
is available through the U.S. Geological Survey.
Go to the USGS Earth Explorer web site
(http//edcsns17.cr.usgs.gov/EarthExplorer/) or
their newer, better web browser
(http//glovis.usgs.gov). A. How many Landsat TM
scenes are needed to image the entire state of
New Jersey? B. What are the Path/Row
numbers? C. What is the cost per square km for
the ETM Level 1G image? Hint 1st
determine the area of the scene in km2, then
divide scene cost by area D. Using the Search
Archive capabilities, determine the date of the
most recent cloud-free (lt20) ETM image for
Middlesex County, NJ. What is the Scene ID,
Path/Row and date?
67
Homework 1 Selecting and Ordering Imagery 2.
The OrbImage Corporation (www.orbimage.com/)
markets OrbView and other high resolution
imagery. Access the OrbImage site to get
up-to-date information on pricing and
availability. A. What is the spatial accuracy
and cost per square kilometer for the standard
OrbView Cities product? OrbView Cities Plus? 3.
DigitalGlobe (www.digitalglobe.com) markets
Quickbird imagery. Access the DigitalGlobe site
to get up-to-date information on pricing and
availability? A. What types of Quickbird image
products are offered?
68
Good Bye from Planet Earth
Source http//visibleearth.nasa.gov/
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