A linear systems approach to evaluating imaging arrays

The authors examine methods of varying the standard modulation transfer function analysis approach to accommodate sensor sampling. Sampled imaging arrays such as charge-coupled devices do not satisfy the spatial shift-invariance criteria,which is required to apply traditional linear systems analysis techniques. The nonisoplanatic condition in imaging arrays is due to the phase dependency of the image position relative to the fixed pixel locations. A procedure to effectively eliminate the spatial phase dependency by using linear systems procedures to model image sampling and then averaging the image scene over the pixel sampling centers is described. A modulation transfer function expression is formulated which yields a statistical estimate of the spatial frequency response of any type of linear or area imaging array