A glasses-free (auto-stereoscopic) 3D display that will serve several viewers who have freedom of movement over a
large viewing region is described. This operates on the principle of employing head position tracking to provide regions
referred to as exit pupils that follow the positions ofthe viewers' eyes in order for appropriate left and right images to be
seen. A non-intrusive multi-user head tracker controls the light sources of a specially designed backlight that illuminates
a direct-view LCD.
Many 3D systems work by presenting to the observer stereoscopic pairs of images that are combined to give the
impression of a 3D image. Discomfort experienced when viewing for extended periods may be due to several factors,
including the presence of optical crosstalk between the stereo image channels. In this paper we use two video cameras
and two LCD panels viewed via a Helmholtz arrangement of mirrors, to display a stereoscopic image inherently free of
crosstalk. Simple depth discrimination tasks are performed whilst viewing the 3D image and controlled amounts of
image crosstalk are introduced by electronically mixing the video signals. Error monitoring and skin conductance are
used as measures of workload as well as traditional subjective questionnaires. We report qualitative measurements of
user workload under a variety of viewing conditions. This pilot study revealed a decrease in task performance and
increased workload as crosstalk was increased. The observations will assist in the design of further trials planned to be
conducted in a medical environment.
De Montfort University, in conjunction with the Heinrich Hertz Institute, is developing a 3D display that is targeted specifically at the television market. It is capable of supplying 3D to several viewers who do not have to wear special glasses, and who are able to move freely over a room-sized area. The display consists of a single liquid crystal display that presents the same stereo pair to every viewer by employing spatial multiplexing. This presents a stereo pair on alternate pixel rows, with the conventional backlight replaced by novel steering optics controlled by the output of a head position tracker. Illumination is achieved using arrays of coaxial optical elements in conjunction with high-density white light emitting diode arrays. The operation of the steering and multiplexing optics in the prototype display are explained. The results obtained from a prototype built under the European Union-funded ATTEST 3D television project are described. The performance of this model was not optimum, but was sufficient to prove that the principle of operation is viable for a 3D television display. A second prototype, incorporating improvements based on experience gained, is currently under construction and this is also described. The prototype is capable of being developed into a display appropriate for a production model that will enable 3D television to come to market within the next ten years. With the current widespread usage of flat panel displays it is likely that customer preference will be for a hang-on-the-wall 3D display, and this challenge will be met by reconfiguring the optics and incorporating novel optical addressing techniques.
De Montfort University (DMU) has developed an autostereoscopic display that is targeted specifically at television applications. The display is capable of supplying 3D images to multiple viewers who are not required to wear special glasses, and who are able to move freely over a room-sized area. It operates by producing regions (exit pupils) in the viewing field where either a left or a right image is seen. The positions of the exit pupils are steered to the viewers’ eyes by the use of head tracking. The DMU display consists of an LCD whose conventional backlight is replaced by a steerable optical configuration that is capable of producing several pairs of exit pupils. Left and right images are produced on alternate pixel rows of a single UXGA LCD. This spatial image multiplexing is achieved by the use of a lenticular sheet located between the steering optics and the LCD. The steering optics can produce exit pupils over a large area, but without the aberration and coloration effects associated with other methods. This is achieved using arrays of coaxial lenses in conjunction with high-density white LED array sources.