Progress Overview of Capturing Method for Integral 3-D Imaging Displays

An integral 3-D technique provides a 3-D spatial image viewable from varying positions without the use of special light sources or viewing glasses. Therefore, this technique shows promise for diverse applications in various fields, including 3-D television broadcasting, advertising, and medical diagnostics. However, there are problems in capturing and displaying large amounts of information in realizing practical integral imaging devices. This paper overviews integral 3-D capturing methods and analyzes integral 3-D imaging technology at its capturing and displaying stages. To overcome the resolution problem, it also introduces our recent work for capturing high-resolution integral imaging information. The introduced device consists of a multiple-lens array and a complementary metal-oxide-semiconductor image sensor with a circuit patterned using multiple exposures. This device can capture depth-controlled spatial information by introducing additional optics. Two types of optics for depth control are applied to the capturing device: one functions as a convex lens to control and compress a relatively large object space and the other functions as an afocal lens array that controls a relatively small object space without any distortion in the depthwise direction. Experimental results of spatial information capturing and 3-D image displays confirm that the method produces 3-D images having an appropriate motion parallax. The presented method is scalable; thus, this technique offers possibilities for developing advanced high-resolution integral 3-D imaging devices.

I. Introduction

Integral photography (IP) is a technique proposed by Lippmann for making 3-D photographs that do not require special glasses or a light source such as coherent light [1]. Precision processing techniques for optical devices and high-resolution film are required to generate high-quality 3-D images. Displaying a 3-D movie in real time using an IP method necessitates replacing film with electronic devices, such as complementary metal–oxide–semiconductor (CMOS) image sensors and liquid crystal display (LCD) panels. In recent years, interest in integral imaging, which is a technique for generating 3-D movies, has kept pace with the development of high-resolution electronic devices [2], [3]. Integral imaging is applied in a wide range of applications, such as 3-D movie displays, extraction and tracking of objects [4], [5], conversion to holograms [6]–[8], refocusing [9]–[13], and user interfaces [14].