WPM P2.07 PERSON ADAPTIVE AUTOSTEREOSCOPIC MONITOR (PAM)

Siegbert Hentschke, Andreas Herrfeld, Markus Andiel, and Matthias Hildebrand

University of Kassel, Wilhelmshoher Allee 71, 34109 Kassel, Germany

Abstract

The PAM is an autostereoscopic monitor that presents three dimensional pictures and scenes to the user. It avoids moving glasses and can be added very easily to any computer system with a flat panel TFT display.

Basics of Stereoscopic Imaging

Stereoscopic impressions are obtained by the perception of two (slightly) different images with the right and the left eye. Conventional viewing systems like TV-sets or computer monitors present images, scenes, or films only in 2D. But, new 3D imaging systems have been developed in recent years that allow one or more users to look at three-dimensional pictures. One of our designs, the 3D Photo Display, has been presented at the ’99 ICCE [ 11. It offers up to 100 views of a single object where all information is stored on a single high resolution film. Our new development is a person-adaptive autostereo- scopic monitor (PAM). The main difference is that the PAM calculates each new picture that should be presented to a viewer in real time. Before illustrating the structure of the PAM, we first would like to summarize the principle of stereoscopic imaging.

Realizations of 3D Imaging Systems

Stereoscopic methods of filming and projection have been in use for years. Most methods use polarizing light (horizontally, vertically, and

circularly), or the shutter-technique in order to separate the right from the left picture.

Autostereoscopic presentations can be realized by beaming different views on lenticular glasses from different projection directions. The sum of the reflecting projections permits a 3D visual perception. However, it is almost impossible to achieve a continuous transition from one view to the next, because the number of projection directions cannot be enlarged arbitrarily. The autostereoscopic display for one single user, emits only two views, with respect to user’s position. A fully stereoscopic picture like in a hologram is achieved by use of head traclung sensors that control the high-capacity real-time computer for calculating the fitting stereoscopic views on the one hand, and on the other hand control the autostereoscopic display for mechanical adjustment of the lenticular glasses grid shield. Furthermore, expensive VR-systems utilizing head mounted displays are in use.

Person Adaptive Monitor PAM

The PAM now is an autostereoscopic monitor that avoids moving glasses and that can be added very easily to any computer system. An existing computer system can be expanded by a prism- lens glass in front of display’s screen, a head tracker, and a special pixel coding interface. The special glass can be fixed on the TFT-display or removed in the standard 2D mode. The head tracker is used to detect the position of the observer and to submit its position to the graphic computer and to the pixel interface. Which evaluates the signals of the head tracker. The main task is the adaptively subpixel recoding

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depending on the observers position. The subpixel recoding is done by the following restoring operation of alternating mixed pixel B(i,r) of the left and right picture into the subpixel store Bsp(n) of the used TFT panel:

Bsp(n) = B(i,r); 0 I. i < Imax-l;

(e.g. I,a,=1280), 0 2 r i 2 , n I3*(Imax -1)

n counting the subpixel, i the leftlright pixel, r the 3 colors,

with n = ho + r + int(iepitcM2) and

r = n mod(3) .

ho = int[(%+h)/l6].

Where is a starting value for the line and ho is a value of the horizontal position of the observer coming from the head tracker. A more detailed

description of the algorithm will be presented at the conference.

Because this real time processing was the most critical point, we implemented this algorithm on a hardware board. In this way the real time algorithm could be optimized to test several different parameters of the adaptive system.

The result of our development is a simple add-on component for any computer workstation with a flat panel TFT display. This component offers users the additional autostereoscopic 3D-mode. Our actual work concerns the development of 3D-software that can be individually installed on the PAM computer.

References

[l] Hentschke, S.; Herrfeld, A.; Kreuzer, E.M.; Eidenschink, R.; Schmitz, J.: Hologram Display Model, ZEEE Zntemational Conference on Consumer Electronics, Paper WAM P1.l, pp.130-131, 1999.

Block diagram of the Person-adaptive Autostereoscopic Monitor (PAM)

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