<title>Optical preconditioning and digital image restoration</title>

Abstract

Appropriate modifications of the image-capture process in a modern imaging system can potentially enhance the digital restorability of the collected image data and thus lead to improved final-image quality. Examples of such modification are insertion of a phase mask in the pupil that encodes depth dependent intensity distribution in the wavefront, insertion of a specific defocus phase in one of the two arms of a conventional phase-diverse speckle imaging system, and use of progressively larger sub-pixel tip-tilts in the otherwise identical low-resolution image channels of an array imaging system. In each case, the final reconstructed image has a higher quality than the intermediate raw image(s) recorded by the sensor. This paper discusses the application of Fisher information to characterize the performance of these three model imaging systems that exploit optical preconditioning to improve the digital restorability and thus the quality of the final image.