Optical: systems and elements – Single channel simultaneously to or from plural channels – By partial reflection at beam splitting or combining surface
Patent
1995-08-29
1998-01-27
Nelms, David C.
Optical: systems and elements
Single channel simultaneously to or from plural channels
By partial reflection at beam splitting or combining surface
G02B 2714
Patent
active
057127328
DESCRIPTION:
BRIEF SUMMARY
This invention is concerned with the field of three-dimensional imaging and specifically with co-ordinate tracking and single-user display applications in which the position of the observer is used as feedback to the display system.
BACKGROUND
There are various ways of producing a three-dimensional image, in which the viewer's left and right eyes observe different perspectives of the same subject, thus creating a sensation of depth and separation between foreground and background. Some systems are based on providing only two perspectives. In these cases, it is normal to use special eyewear (such as polarising or anaglyphic filters) which transmit the appropriate image to each eye. In another type of system, a continuum or plurality of perspectives, combined in interdigitated form behind a lenticular screen, is projected by this screen, so that in use the viewer effectively only observes two of them (one for each eye), without requiring special eyewear to do so. The viewer may alter his position and observe the subject from a new view point. His range of movement is typically limited to some 20 to 30 degrees around the screen if good image quality is to be maintained, and the depth of field is limited by the ability of the optical system to separate adjacent perspectives and avoid the blurring of them. In a further type of system, the aperture (or pupil) of the image projection optics is relatively large, and relayed, using suitable optical elements to the observer's location. An electro-optic and/or electromechanical shutter arrangement, located near the aperture, allows different perspectives to be sequenced using a single display screen, each perspective only being observable at specific locations in space. For real time applications, multiple perspective (autostereoscopic) systems require very high display bandwidth and complex display apparatus. The prior art contains a number of publications which are relevant to the current invention. One which is particularly relevant is entitled "Head Tracking Stereoscopic Display" (A. Schwartz, IEEE Transactions on Electron Devices, Vol.ED-33 No 8, Aug. 1986, pp. 1123-1127). In the Schwartz system, two CRT's are positioned behind corresponding projection lenses. Each CRT produces one image of a stereo pair, the two being rear projected, at slightly different angles, into the back of a Fresnel lens. This lens acts as a highly directional screen by reimaging the pupils of the two projection lenses to points in space corresponding to the possible respective positions of an observer's eyes. By positioning a lenticular screen with its lenses running horizontally at the Fresnel lens, the images of the projection lens pupils are extended vertically into stripes. An observer may now position himself, at the distance at which these stripes are formed from the viewing screen and observe a stereoscopic image. The observer's left. eye must remain located within the vertical stripe comprising light from the CRT producing the left eye image, whereas the observer's right eye must remain within the stripe corresponding to the other CRT, which provides the image for that eye. To allow the observer freedom of head movement, an infrared detection system is used to detect the position the observer's head, and a servo system controls the lateral position of the Fresnel lens, so that the line joining optical centre to the point half way between the two exit pupils of the projection lenses lies in a vertical plane passing between the observer's eyes.
The Schwartz system works, provided the observer is positioned at the required distance from the Fresnel screen. The distance by which this must be moved is roughly half the lateral movement of the observer. The system is inevitably somewhat bulky and large mechanical movements are required to provide substantial scope for lateral head movement. Furthermore, the horizontal width of the Fresnel lens must exceed the useful image width by this amount or the image itself will be truncated when the observer ranges laterally. The Schwartz syst
REFERENCES:
patent: Re35029 (1995-08-01), Sandor et al.
patent: 3834785 (1974-09-01), Kimura
patent: 4641178 (1987-02-01), Street
patent: 4649425 (1987-03-01), Pund
patent: 4872750 (1989-10-01), Morishita
patent: 5287437 (1994-02-01), Deering
patent: 5414544 (1995-05-01), Aoyagi
patent: 5467205 (1995-11-01), Kuba
patent: 5477385 (1995-12-01), Freeman
patent: 5493427 (1996-02-01), Nomura
patent: 5583695 (1996-12-01), Dobrusskin
Schwartz, Head Tracking Stereoscopic Display, Oct. 15-17, 1995, pp. 141-144.
Schwartz, Alfred, 1985 International Display Research Conference, Oct. 15, 1985, San Diego, CA, pp. 141-144, "Head Tracking Stereoscopic Display".
Eichenlaub, J. B., Proceedings on the SPIE: Stereoscopic Displays and Applications IV, vol. 1915, Feb. 1, 1993, San Jose, CA, pp. 177-186, "Developments in Autostereoscopic Technology at Dimension Technologies Inc".
Okoshi, Takanori, Three Dimensional Imaging Techniques, pp. 364-369, Academic Press, 1976.
Isono, Haruo, "Autostereoscopic 3-D Display Using LCD-Generated Active Barrier-Strip", Proceedings on 22nd Image Technology Conference, pp. 103-106, 1991.
Mack Ricky
Nelms David C.
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