Depth measurement using engineered point spread function with coded aperture

Abstract

Depth extraction and recovery from the recorded image have been studied and applied in many fields such as biology, robotics, and computer vision. In some researches, the aperture in the imaging system is coded as a particular function in order to distinguish relative distances from the focal plane or recognize sampled points from the recorded image and the image captured through this coded aperture is useful to retrieve blurred images or acquire depth maps. These studies are associated with the shape of point spread function (PSF). In some approaches, diffraction-based engineered PSFs such as double-helix and cubic phase are applied to extract the depth information. In this paper, we propose a depth measurement method based on the optical analysis of the pupil function. It is well known that the PSF is represented as a Fourier transform of the product of pupil function and spherical phase in a coherent imaging system. Also, it is possible to estimate the intensity of the PSF corresponding to the distance of the object in an incoherent imaging system. Then the depth information is extracted from a snapshot image by inverse transform of the image.