A compound-eye imaging system with irregular lens-array arrangement

Abstract

TOMBO (Thin Observation Module by Bound Optics) is a compound-eye imaging system inspired by a visual organ of insects. TOMBO has various advantages over conventional imaging systems. However, to demonstrate applicability of TOMBO as an imaging system, high-resolution imaging is significant and unavoidable. In this study, a TOMBO system with irregular lens-array arrangement is proposed and a high-resolution imaging method integrating a super-resolution process with depth acquisition of three-dimensional objects is presented. The proposed TOMBO system improves image resolution for far objects, because it can alleviate degeneration of the sampling points on the far objects caused by the regular arrangement of the lens array in the conventional TOMBO system. An experimental TOMBO has 1.3 mm focal length of lens, 0.5 mm pitch of lenses, 0.5 mm diameter of aperture, 3 × 3 of units, 160 × 160 pixels per unit, and 3.125 μm pitch of pixel. The target planar object is located at 5 m from the TOMBO system. The simulation result shows that the coverage ratio of the sampling points, PSNR of the super-resolved image, and the error of the depth estimation for the object are improved by 50%, 3 dB, and 56%, respectively. The experimental result shows that the error of depth estimation for the planar object located at 3.2 m is 18% and that the contrast of 123 lp/mm at the center of a unit is improved by 0.38 with the super-resolution processing.