Point spread function for the wide-field-of-view plenoptic cameras

Abstract

Recently, single or multi-layer spherical lens (monocentric lens) coupled with a microlens array (MLA) and an imaging sensor are under investigation to expand the field of view (FOV) for handheld plenoptic cameras. However, there lacks modeling the point spread functions (PSFs) for them to improve the imaging quality and to reconstruct the light field in the object space. In this paper, a generic image formation model is proposed for wide-FOV plenoptic cameras that use a monocentric lens and an MLA. By analyzing the optical characteristics of the monocentric lens, we propose to approximate it by a superposition of a series of concentric lenses with variable apertures. Based on geometry simplification and wave propagation, the equivalent imaging process of each portion of a wide-FOV plenoptic camera is modeled, based on which the PSF is derived. By comparing PSFs captured by real wide-FOV plenoptic camera and those generated by the proposed model, the validity of this model is verified. Further, reconstruction process is applied by deconvolving captured images with the PSFs generated by the proposed model. Experimental results show that the quality of reconstructed images is better than that of subaperture images, which demonstrates that our proposed PSF model is beneficial for imaging quality improvement and light field reconstruction.