Quote:
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Originally Posted by R.A.F.
Quote:
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Originally Posted by Chip
There can be coloration differences due to the effect of dust storms.
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OOPS!! I didn't "catch" this earlier, but you're absolutely right!!
So, lets see what we have, so far, to explain these Martian geological "changes"...
1. Image Resolution
2. Dust Storms
3. Image Angle
4. Sun Angle
Hmmm...I smell a non-mystery! |
Also,
spectral range and resolution
bit structure of image
image processing tools and techniques
image compression
map projection
I would broaden "image angle" to "viewing geometry"
Those of us in the image analyis and cartography fields know you can not do change detection without high precision spatial co-registration of the images involved. You also have to account for differences in atmosphere (dust in this case), lighting (sun azimuth and altitude), viewing geometry and sensor conditions at the time of acquisition. And that's with SAME SENSOR change detection. Throw in cross or mult-sensor issues and then you have to account for spectral differences, bit structure and any pre processing done on the data.
CJSF