1. A method for evaluating an image, the method comprising: obtaining a computational image, wherein, for each pixel in the computational image, the computational image includes spectral information that describes the spectral values of the pixel when captured using different spectral sensitivities, wherein the spectral image was generated from two or more image captures by one or more tunable imaging sensors, and wherein the one or more tunable imaging sensors were tuned to different spectral sensitivities during the two or more image captures; segmenting the computational image into sub-images based on the spectral information that describes the spectral values of each pixel when captured using different spectral sensitivities; generating respective morphological signatures for the sub-images; generating respective spectral signatures for the sub-images; and generating an image signature based on the morphological signatures and the spectral signatures.