Image gathering and processing for enhanced resolution

Traditional approaches to optical resolution enhancement have involved either the design of appropriate image-formation systems or some type of postprocessing of an image that has already been formed. Results presented in this paper suggest that improved images can be obtained if the image-gathering system is designed specifically to enhance the performance of the image-restoration algorithm to be used. We consider a class of problems in which the total available spatial bandwidth is fixed but the location of this bandwidth along the spatial-frequency axis is to some extent under our control. For example, we might consider either a low-pass system or a bandpass system of the same total bandwidth. We show that system performance can be substantially improved by proper allocation of the available bandwidth in the spatial-frequency domain. The optimum allocation is shown to be a function of the signal-to-noise ratio. We also describe coherent and incoherent optical image-gathering systems that can achieve the desired spatial-frequency passbands.