1. A method for generating a deselect mapping for a focal plane array, the method comprising: gathering a data set for a focal plane array when exposed to light or radiation from a first known target; analyzing the data set for determining which pixels or subpixels of the focal plane array to add to a deselect mapping; adding the pixels or subpixels to the deselect mapping based on the analysis; and storing the deselect mapping to at least a nonvolatile memory, wherein the analysis includes determining which pixels or subpixels have an output greater than a threshold, wherein the threshold varies with spectral dispersion of the light or radiation.