1. A tunable multi-band spectro-polarimetric imaging system comprising: an imaging detector including a two-dimensional array of pixels; an optical sub-system configured to direct the incident electromagnetic radiation from a viewed scene along an optical path to the imaging detector; a first tunable spectral filter positioned in the optical path between the optical sub-system and the imaging detector and configured to filter the incident electromagnetic radiation such that a first plurality of pixels of the array of pixels receives electromagnetic radiation in a first spectral band; a second tunable spectral filter positioned in the optical path between the optical sub-system and the imaging detector and configured to filter the incident electromagnetic radiation such that a second plurality of pixels of the array of pixels receives electromagnetic radiation in a second spectral band different than the first spectral band; a plurality of polarization filters positioned in the optical path between the optical sub-system and the imaging detector, the plurality of polarization filters being configured to selectively alter a polarization state of the incident electromagnetic radiation, such that the imaging detector receives at least three different polarizations of the electromagnetic radiation in each of the first and second spectral bands, the imaging detector being configured to produce first polarimetric image data corresponding to the first spectral band and second polarimetric image data corresponding to the second spectral band; and a controller configured to receive and process the first and second polarimetric image data to detect a target object in the viewed scene, and to provide control signals to the first and second tunable spectral filters to tune a wavelength range of each of the first and second spectral bands.