Visualizing Pattern Constancy

Performance Over Wide-ranging Extraneous Variables and Scene Contents

Time-Series Studies

Each of the following examples shows imagery taken from different times with
changing variables such as sun angle, sensor exposure, noise, dust, and
combinations of all. In each case, the imagery of the same scene from two
different times is enhanced using RVS then edge detection applied.
The two edge patterns are then represented as blue and red. When these colored
patterns are overlaid, corresponding edges are additive and result in a magenta
color. Edges which do not coincide remain blue and red. Resulting composites with
more magenta demonstrate a better match between the two times and thus better pattern
constancy over changing conditions.


Example 1 of 4

Sun angle and dust

In this example, there is a difference in sun angle plus the image at T=2 is slightly
occluded by dust. The RVS enhancement brings out the detail in the ridges very nicely,
providing for a good match between the two image as indicated by the magenta ridges in
the resluting image.

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Responsible NASA Official: Glenn Woodell

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