Image evaluation for optical synthetic aperture imaging system 176

In this paper, the theory of optical synthetic aperture imaging system is described, with emphasis on the image evaluation by the Point Spread Function (PSF) and Optical Transfer Function (OTF). The optical synthetic aperture imaging technique achieves higher resolution at the cost of decreasing of Modulation Transfer Function (MTF) in near mid-band regions, and of increasing the sidelobes of the PSF. The image evaluation methods for optical synthetic aperture imaging system are given, such as two-point resolution criterion and MTF. The disadvantage of evaluation methods is analyzed by Rayleigh criterion, Sparrow criterion and threshold criterion. The conclusion is that the imaging quality of synthetic aperture system is no better than that of the single sub-aperture system when the sidelobe is 0.5 times of the central lobe of the PSF. Finally, we propose new evaluation criterions, such as the efficiency factor and quality factor, which are directly linked to MTF.