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.
This paper describes recent advances in the field of autostereoscopic display development and introduces an appropriate integration of a novel user interaction technology. Beside technical aspects of the developed autostereoscopic display technology, the paper includes topics of our video-based interaction technique and introduces promising applications of autostereoscopic single user displays. Based on results of the European ATTEST project, the Fraunhofer Institute for Telecommunications (HHI) has developed the Free2C 3D display technology, which provides free positioning of a single viewer. The optics of the Free2C displays is designed such that extremely low crosstalk, excellent color reproduction and high brightness are achieved. Simple and intuitive interaction is a requirement for multi-modal 3D displays. For this reason, a novel technology has been integrated into the control console that can recognize a persons' hand and its gestures. Displayed 3D objects floating in front of the screen can be rotated by simple gestures and virtual buttons can be pressed by pointing at them (virtual 3D touch screen). Several applications are currently used by customers and have been presented at trade shows, exhibitions and showrooms. Feasible applications are based on computer generated content, live video created by stereoscopic cameras and films stored on hard disk. Immersive media presentations are one promising application for attractive stereoscopic representations. The Free2C Kiosk and the 3D Media Center combine a high-resolution autostereoscopic 3D display with a video-based hand-gesture recognition device for direct manipulation of virtual 3D objects floating in front of the screen.
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.
This paper describes recent advances in a number of R&D areas that are believed to provide 'key technologies' for the further development of a novel, digital, broadcast 3D-TV system. The provided results are part of the outcome of the European IST project ATTEST (Advanced Three-Dimensional Television System Technologies), a two-year research initiative that was finalized in March 2004. The paper covers some essential parts of the envisaged 3D signal processing chain such as the real-time generation of "virtual" stereoscopic views from monoscopic color video and associated per-pixel depth information as well as the efficient compression and the backwards-compatible transmission of this advanced data representation format using state-of-the-art video coding standards such as MPEG-2 (color data) and MPEG-4 Visual, resp. Advanced Video Coding (depth data). Furthermore, the paper also describes the development of a new, single-user autostereoscopic 3D-TV display (Free2C). This novel, high-quality 3D device utilizes a lenticular lens raster to separate two individual perspective views, which are presented simultaneously on an underlying LC panel. To provide the user with a satisfying 3D reproduction within a sufficiently large viewing area - a major problem for many state-of-the-art autostereoscopic 3D displays - the lenticular is constantly readjusted according to the viewer's actual head position, which is measured by a highly accurate, video-based tracking system. This approach allows for a variation of the viewing distance within a range of 400 mm to 1100 mm as well as horizontal head movements within a range of about ±30°. The feasibility of the new 3D-TV concept is proved through extensive human factors evaluations of the before-described algorithms and components.