1. A method of target detection from hyper-spectral image data comprising a plurality of pixels comprising target spectra of target material and background spectra of background material, the method comprising: determining first filter coefficients using circuit means to perform constrained linear programming optimization based on the hyper-spectral image data, the target spectra, and an estimated background spectra; applying a filter comprising the first filter coefficients to the hyper-spectral image data to obtain first filtered pixels; and identifying first target pixels from the first filtered pixels.