Matthew C. Forman

Continuous parallax in discrete pixelated integral three-dimensional displays

An evaluation of the retention of continuous parallax in pixelated integral three-dimensional image displays is presented. The integral image capture process is first considered, to provide a starting point for the investigation. The complementary display system is then examined in detail. The viewing geometry of the display system is analyzed to provide a foundation for the work to follow, and an experimental investigation and simulations of the characteristics of emitted ray bundles are presented. Next, an analytical model of decoding lenslet array operation is derived, leading to an understanding of the process responsible for production of continuous parallax in replay. It is found that if the lateral resolution of the lenslet is matched to that of the display, continuous parallax is retained in the replayed image, where the finite aberration-limited resolution of the lenslet acts to produce a low-pass reconstruction filter. A condition is derived for optimal continuous parallax in replay, based on a relationship between pixel width and lenslet rms spot size.

A novel coding scheme for full parallax 3D-TV pictures

A unique integral imaging system is employed as part of a three dimensional television system, allowing display of full colour 3D images with continuous parallax within a wide viewing zone. A significant quantity of data is required to represent captured integral 3D images with adequate resolution. A a lossy compression scheme is described, based on the use of a three dimensional discrete cosine transform (3D-DCT), which makes possible efficient storage and transmission of such images while maintaining all information necessary to produce a high quality 3D display. The results of simulations performed using the 3D-DCT algorithm are presented and it is shown that the rate-distortion performance is vastly improved compared with that achieved using baseline JPEG, with captured integral 3D image data.

Electronic capture and display of full-parallax 3D images

Integral Imaging is a method of recording full parallax 3D images which may offer an alternative to stereoscopic techniques, such as multi-view systems, for domestic 3D-TV. Previous understanding of integral images indicates that the required recording and display resolution is in excess of that available in current electronic imaging systems. This, in conjunction with the difficulty of manufacturing high quality micro-optical arrays has precluded wide spread research into integral imaging. An advanced form of Integral Image generation which has been previously described is re-examined with respect to new experimental evidence, which suggests that resolution requirements are far less stringent than currently believed. An outline of a possible integral-3DTV system is given. The novel application of existing compression schemes is described, which shows that the bandwidth requirements for Integral 3DTV are the same as for HDTV.

Objective quality measurement of integral 3D images

At De Montfort University the imaging technologies group have developed an integral imaging system capable of real time capture and replay. The system has many advantages compared with other 3D capture and display techniques, however one issue that has not been adequately addressed is the measurement of the fidelity of replayed 3D images where some distortion has occurred. This paper presents a method for producing a viewing angle-dependent PSNR metric based on extraction of optical model data as conventional images. The technique produces image quality measurements which are more relevant to the volume spatial content of an integral image than a conventional fidelity metric applied to the raw, optically encoded spatial distribution. Comparisons of the previous, single metric with the new angle-dependent metric are made when used in assessing the performance of a 3D-DCT based compression scheme, and the utility of the extra information provided by the angle dependent PSNR is considered.

Compression of full-parallax integral 3D-TV image data

An integral imaging system is employed as part of a three dimensional imaging system, allowing display of full color images with continuous parallax within a wide viewing zone. A novel approach to the problem of compressing the significant quantity of data required to represent integral 3D video is presented and it is shown that the reduction in bit cost achieved makes possible transmission via conventional broadcast channels.

The use of computer generated integral images to visualise cyber-sculpture

Over the past decade there has emerged a growing number of sculptors, from around the globe, who have found a use for the computer in their research and practice. For some it offers a design tool but for others it has become a new media. A new integral imaging system capable of real-time capture and replay and methods of computer generation of synthetic integral images has been developed. Keith Brown, a sculptor was intrigued at the possibilities this offers as a means through which to realize cyber-sculptures as true 3D optical constructs. This paper presents the most recent results of the collaboration between Keith Brown and the Imaging Technologies Group at De Montfort University.

Integral imaging as a modality for 3D TV and displays

The development of 3D TV systems and displays for public use require that several important criteria be satisfied. The criteria are that the perceived resolution is as good as existing 2D TV, the image must be in full natural colour, compatibility with current 2D systems in terms of frame rate and transmission data must be ensured, human-factors concerns must be satisfied and seamless autostereoscopic viewing provided. There are several candidate 3D technologies, for example stereoscopic multiview, holographic and integral imaging that endeavor to satisfy the technological and other conditions. The perceived advantages of integral imaging are that the 3D data can be captured by a single aperture camera, the display is a scaled 3D optical model, and in viewing accommodation and convergence are as in normal sighting (natural) thereby preventing possible eye strain. Consequently it appears to be ideal for prolonged human use. The technological factors that inhibited the possible use of integral imaging for TV display have been shown to be less intractable than at first thought. For example compression algorithms are available such that terrestrial bandwidth is perfectly suitable for transmission purposes. Real-time computer generation of integral images is feasible and the high-resolution LCD panels currently available are sufficient to enable high contrast and high quality image display.