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.

A three-dimensional (3-D) television based on the spatial imaging method using integral photography (integral 3-D television) has three main advantages; displaying 3-D images without having to use special 3-D glasses, being viewable without restricting viewer posture, having a system applicable to live broadcasting service. I describe the principle of an integral 3-D television and introduce an experimental integral 3-D television with 33-mega-pixel imaging devices. In this experimental television, a lens array is configured of 400 lenses in the horizontal direction and 250 lenses in the vertical direction. The results from capture and display experiments confirm 3-D video reproduction that changes seamlessly with viewing position.

A three-dimensional (3-D) television system based on integral photography, which is a spatial imaging method, is described. In our experimental setup, a video system has a resolution equivalent to 8000 scan lines and a lens array is configured with 400 lenses in the horizontal direction and 250 lenses in the vertical direction. It was confirmed that the 3D image reconstructed with the experimental setup changed smoothly in accordance with the position of the observer within a viewing area.

The authors discuss practical problems, focusing, and accuracy of lens arrays involved in constructing integral imaging systems. In general, it is recommended to set the focusing for the object during capture to infinity. The positional error of the elemental lens arrangement significantly affects the image quality when the image is reconstructed near the observer. An experimental system in consideration of the practical problems that uses an extremely high resolution video system is described. Some pictures obtained by the system show the specific characteristics of this spatial imaging type of system.