A computer program has been derived to quantitatively compare electro-optical systems through the distribution of charge within discrete sensor arrays. The total effect of optical components and discrete detectors on point source inputs is found by utilizing both theoretical and empirical values of MTF and transmission as a function of wavelength. Data output includes responsivity and effective quantum efficiency without regard to the MTF effects of the system. Then, the total energy spectrum is convolved spatially and spectrally over a 7 x 7 matrix to obtain S/N and total signal in each element. The effects of optics and CCD pixel sizes on point source imaging are shown.