Design and Implementation of a Cooke Triplet based Wave-front Coded Super-resolution Imaging System

Wave-front coding is a powerful technique that could be used to extend the DOF (depth of focus) of incoherent imaging system. It is the suitably designed phase mask that makes the system defocus invariant and it is the de-convolution algorithm that generates the clear image with large DOF. Compared with the traditional imaging system, the point spread function (PSF) in wave-front coded imaging system has quite a large support size and this characteristic makes wave-front coding be capable of realizing super-resolution imaging without replacing the current sensor with one of smaller pitch size. An amplification based single image super-resolution reconstruction procedure has been specifically designed for wave-front coded imaging system and its effectiveness has been demonstrated experimentally. A Cooke Triplet based wave-front coded imaging system is established. For a focal length of 50 mm and f-number 4.5, objects within the range [5 m, infinity] could be clearly imaged, which indicates a DOF extension ratio of approximately 20. At the same time, the proposed processing procedure could produce at least 3x resolution improvement, with the quality of the reconstructed super-resolution image approaching the diffraction limit.