14. The system as recited in claim 11 , wherein said decomposition process includes: a matching pursuits decomposition to generate a linear combination of said core spectral signatures for an individual pixel, and an adjustment of coefficients in said linear combination for statistical optimization thereof.
11. The system as recited in claim 10 , wherein the image data is captured to include multi- or hyper-spectral pixels; and, said simultaneous sparse approximation process is of a greedy adaptive decomposition (GAD) type executed upon at least one selectively grouped set of image pixels.