ASTER bands 3N and 3B look in different directions, 3N towards nadir and 3B to the rear or backwards. This pair of images extracted from an ASTER scene has been rotated so that a horizontal line on the screen represents the along-track movement of the spacecraft. The distance between the images causes parallax, a slight shift in viewpoint that mimics binary vision. The viewer can use a stereo viewing device to see the scene in 3-dimensions or merely stare at the screen allowing the images to converge. (With practice the image will pop out in 3-D within a minute. Deliberately "crossing" the eyes speeds up the process. Occasional use of this method of viewing stereo images will cause no harm, but frequent use could cause eye-strain and headaches.)
The author has visited this site. The relief seen in the image is very exaggerated compared to what exists in reality.
Computer algorithms have been developed to convert the elevation information in stereo pairs to numerical values from which digital terrain models (DEMs) can be constructed. ASTER images can therefore be used to make topographic maps.
