[erdmann]

Yes, and the vignetting pattern isn't so much the problem. It's a color distortion problem (spatially varying chromaticity rather than brightness that is not just a function of the position within the field of view but also of the underlying material, unfortunately). So there isn't a nice way to correct each capture in a predictable way to ensure that overlapping pixels have the same colors consistently.

[snovv_crash]

I've worked with similar problems for agricultural mapping from drone images. You would need to build a BRDF model for the different colour channels for various types of materials, then assign the material based on a combination of best representative models. Then you can re-render with uniform normal lighting.

[thomas43]

i see. interesting problem

[triplesec]

Anyone have a nice primer to read to help nonspecialists understand what you are talking about in this thread here?

[chaboud]

They are talking about a bidirectional reflectance distribution function, a now common modeling technique for practical representation of complex surface properties when illuminated.

That said, a full BRDF is not the only way to approach this problem, especially at reduced resolution where the artifacts are more apparent.

If you're an ACM member, there is a wealth of information in SIGGRAPH publications. Having been in graphics since the 90s, I started with Foley and Van Dam (Computer Graphics: Principles and Practice) and Watt and Watt (Animation and Rendering Techniques) and then stayed on top of SIGRAPH (attending regularly, though not annually) since then.

For a more whimsical survey from the pen of a straight up genius, Jim Blinn's books (e.g. Dirty Pixels) are fantastic reads.