xviii Figures
FIGURE 1-16. The four sensor chip assemblies (SCAs) in the ALI. ........................................... 27
FIGURE 1-17. The pushbroom 2-D array concept used in the HYDICE, Hyperion, and MERIS
hyperspectral sensors. ........................................................................................... 28
FIGURE 1-18. The 2-D detector array layout used in HYDICE. ................................................. 29
FIGURE 1-19. Visual comparison of ETM+ whiskbroom and ALI pushbroom imagery acquired on
July 27, 2001, of center-pivot irrigated agricultural fields near Maricopa, Arizona.
.............................................................................................................................. 31
FIGURE 1-20. Visual comparison of ETM+ whiskbroom and ALI pushbroom panchromatic
imagery of an area in Alaska acquired by ETM+ on November 27, 1999, and ALI
on November 25, 2000. ........................................................................................32
FIGURE 1-21. Spectral ranges for the 36 MODIS bands. ............................................................ 33
FIGURE 1-22. Four MODIS image bands collected on March 2, 2006, showing James Bay,
Canada, at the top, the Great Lakes in the middle, and Florida at the bottom. .....34
FIGURE 1-23. The three most common multispectral image formats: BIS, BSQ, and BIL,
illustrated with an 8 sample-by-8 line-by-7 band TM image. ..............................37
FIGURE 1-24. The conversion from DN to GL to color in a 24bits/pixel digital video display...38
CHAPTER 2 Optical Radiation Models
FIGURE 2-1. Comparison of the exo-atmospheric (top-of-the-atmosphere) solar spectral
irradiance as used in the atmospheric modeling code MODTRAN (Berk et al., 1989)
to the blackbody curve for T = 5900K. ................................................................47
FIGURE 2-2. Spectral distributions at the top-of-the-atmosphere for the two radiation sources in
the visible through thermal infrared spectral regions. ..........................................48
FIGURE 2-3. The most significant radiation components seen by the sensor in solar reflective
remote sensing are the “direct” component, the “skylight” component, and the “path
radiance” component (commonly called “haze”). ................................................49
FIGURE 2-4. Transmittance of the atmosphere as calculated by the program MODTRAN...... 50
FIGURE 2-5. Solar irradiance in the visible and shortwave IR regions (for a solar elevation angle
of 45°), above the atmosphere and at the earth’s surface. ....................................51
FIGURE 2-6. The geometry of solar direct irradiance on the earth’s surface............................. 52
FIGURE 2-7. Atmospheric path transmittance as viewed by a satellite sensor. ......................... 54
FIGURE 2-8. The path-scattered and ground-reflected components of the total upwelling radiance
seen by a satellite sensor for a surface reflectance of Kentucky Bluegrass. .........56
FIGURE 2-9. The spectral response of Kentucky Bluegrass as predicted by the MODTRAN
model and a plot of a mixed grass and trees response from the AVIRIS image of
Palo Alto (Plate 1-3). ............................................................................................57