title: Optical full-depth refocusing of 3-D objects based on subdivided-elemental images and local periodic δ-functions in integral imaging.
abstract: We propose a new approach for optical refocusing of three-dimensional (3-D) objects on their real depth without a pickup-range limitation based on subdivided-elemental image arrays (sub-EIAs) and local periodic δ-function arrays (L-PDFAs). The captured EIA from the 3-D objects locating out of the pickup-range, is divided into a number of sub-EIAs depending on the object distance from the lens array. Then, by convolving these sub-EIAs with each L-PDFA whose spatial period corresponds to the specific object's depth, as well as whose size is matched to that of the sub-EIA, arrays of spatially-filtered sub-EIAs (SF-sub-EIAs) for each object depth can be uniquely extracted. From these arrays of SF-sub-EIAs, 3-D objects can be optically reconstructed to be refocused on their real depth. Operational principle of the proposed method is analyzed based on ray-optics. In addition, to confirm the feasibility of the proposed method in the practical application, experiments with test objects are carried out and the results are comparatively discussed with those of the conventional method.
authors.forename: Ling-Yu
authors.initials: LY
authors.lastname: Ai
authors.forename: Xiao-Bin
authors.initials: XB
authors.lastname: Dong
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Eun-Soo
authors.initials: ES
authors.lastname: Kim