Image quality assessment of sparse aperture designs with decreasing fill factors

Sparse aperture designs can increase the effective aperture size of a remote sensing system, thus allowing the satellite to be placed in a higher orbit without compromising the resolution. The fill factor of a sparse aperture is the total area of the telescope apertures divided by the effective aperture size of the combined telescopes. Reducing the fill factor, F, reduces the overall weight, but also reduces both the signal and the MTF (modulation transfer function). Increasing the effective integration time, t, and applying Wiener filters can gain back some of the lost image quality. This study generated image simulations of various sparse aperture designs to assess the image quality as a function of fill factor. This study found that the integration time needs to be increased by a factor of 1/F-2 - 1/F-3 in order to maintain the image quality as the fill factor decreased. This study also found that the GIQE (Generalized Image Quality Equation) did not accurately predict the change in image quality, in Delta NIIRS, as the fill factor is reduced.