Refocusing-range and image-quality enhanced optical reconstruction of 3-D objects from integral images using a principal periodic δ-function array

We propose a method for refocusing-range and image-quality enhanced optical reconstruction of threedimensional (3-D) objects from integral images only by using a 3 x 3 periodic delta-function array (PDFA), which is called a principal PDFA (P-PDFA). By directly convolving the elemental image array (EIA) captured from 3-D objects with the P-PDFAs whose spatial periods correspond to each object's depth, a set of spatially-filtered EIAs (SF-EIAs) are extracted, and from which 3-D objects can be reconstructed to be refocused on their real depth. convolutional operations are performed directly on each of the minimum 3 x 3 EIs of the picked-up EIA, the capturing and refocused-depth ranges of 3-D objects can be greatly enhanced, as well as 3-D objects much improved in image quality can be reconstructed without any preprocessing operations. Through rayoptical analysis and optical experiments with actual 3-D objects, the feasibility of the proposed method has been confirmed. (C) 2017 The Authors. Published by Elsevier B.V.