The influence of phase mask position upon EDoF system

Abstract

Special types of pupil mask with the appropriate phase and transmission distribution can be used to modify the 3D point-spread function (PSF) in the desired way. Recently, many studies were addressed to extend the depth-of-field (EDoF) of an imaging system via cubic phase pupil engineering. The intermediate image is detected with a digital sensor and the final image formation is restored by post-process algorithms with the help of knowledge of the pupil mask. The EDoF system is operated based on an assumption that the phase mask should be positioned exactly in the pupil of the optical system. Unfortunately, in most practical cases, the exit pupil is not always available due to the complex layout of a compound lens set and results in a limited practical benefit of this type of arrangement. In this paper, we present the influence of the phase mask position upon PSF of an extended depth-of-field system. The characterizations of EDoF in different viewing angles are dissimilar if the phase mask is not placed in the perfect pupil plane. Such properties should be taken into consideration while designing an EDoF system. Finally, we will propose some potential candidate lenses made to alleviate such difficulty.