A system, circuit and methods for target detection from hyper-spectral image data are disclosed. Filter coefficients are determined using a modified constrained energy minimization (CEM) method. The modified CEM method can operate on a circuit operable to perform constrained linear programming optimization. A filter comprising the filter coefficients is applied to a plurality of pixels of the hyper-spectral image data to form CEM values for the pixels, and one or more target pixels are identified from the CEM values. The process may be repeated to enhance target recognition by using filter coefficients determined by excluding the identified target pixels from the hyper-spectral image data.