Dual coaxial lens system for depth reconstruction

Abstract

Depth information can be acquired using two different projection images, namely, an orthogonal projection image and a perspective projection image. A dual-lens optical system is able to simultaneously take these projection images in a coaxial frame. The dual-lens optical system consists of a telecentric lens, an entocentric lens, and a dichroic mirror, which can acquire the different projection images separated by color. The dual-lens optical system is shown to be more compact by means of two coaxial band-pass filters. The different projection images separated by color are radially deviated from each other where object features at each depth on the perspective projection image are similar transformation of those on the orthogonal projection image. This means that matching of the object features for depth reconstruction is needed to be performed only in a radial direction with the similarity transformation. Using such constraint, the optical system is validated by an experiment, showing that the proposed optical system can be used for depth reconstruction.