Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
1999-07-30
2004-12-14
Lee, Young (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
Reexamination Certificate
active
06831948
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of color image displays, and more particularly to color displays in which the color image planes are separately updated or displayed. The invention also relates to compensation of motion images for artifacts introduced by a discrete time representation thereof.
BACKGROUND OF THE INVENTION
Color image displays are of two general types. In a first type, exemplified by a typical direct-view cathode ray tube color display, all color image components are displayed simultaneously. Thus, an image model, e.g., a CCIR-601 signal, defines the luminance and chrominance of each image pixel at a particular time. The motion image is therefore presented as a time sequence of color image frames.
In a second type of color image display, color image planes are displayed sequentially. This type of system is employed, for example, in certain single panel image projection systems, in which light of various colors sequentially illuminates a common spatial light modulator. The spatial image modulator, therefore, modulates the intensity of each respective color component of a pixel sequentially and independently, which is perceived as a color motion image.
Sequential color displays work well as long as one pixel is being observed during an entire frame time. When a moving object is present, the eyes are focussing on this object, and the eyes start tracking the motion. The color breakup artifact that an observer notices at that moment is caused due to tracking of the motion by the eyes, i.e. the eyes follow a moving object by rotating the head and eyes while keeping this object focussed on the same position on the retina.
Color sequential displays display the Red, Green, Blue (RGB) colors alternating during a frame time, as represented in FIG.
1
. This frame time might have a small delay for each successive row, depending on the way the color sequential illumination is implemented, but this time delay is generally considered negligible. The image pixels are observed at different time moments within a frame period, and thus might display different video data for the RGB colors other than the intended one. If this happens when the video data of these pixels changes, at that moment a color break-up artifact is visible.
JP 08-123355 A, published May 17, 1996, relates to a motion compensation system for a plasma display panel. In this system, the image motion artifact caused by the tracking of the human eye of motion of a displayed object between successive frames, in a display system having pulse modulated gray scale generation, representing a plurality of image subframes differing in brightness, is corrected by calculating object motion and moving the object within the image for correction at the time of display.
The following references are hereby incorporated herein by reference in their entirety:
W. Bruls, A. van der Werf, R. Kleihorst, T. Friedrich, E. Salomons and F. Jorritsma, “A single-chip MPEG-2 encoder for consumer storage applications”
Digest of the ICCE,
1997, Chicago, pp. 262-263.
G. de Haan and H. Huijgen, “Motion estimation for TV picture enhancement”, in
Signal Processing of HDTV III
, (H. Yasuda and L. Chiariglione, eds.), Elseviers Science Publishers B.V., 1992, pp. 241-248.
G. de Haan, J. Kettenis, and B. Deloore, “IC for motion compensated 100 Hz TV, with a smooth motion movie-mode”,
IEEE Transactions on Consumer Electronics
, vol. 42, May 1996, pp. 165-174.
G. de Haan, P.W.A.C. Biezen and O. A. Ojo, “An Evolutionary Architecture for Motion-Compensated 100 Hz Television,” in
IEEE Transactions on Circuits and Systems for Video Technology, Vol.
5, No. 3, June 1995, pages 207-217.
“Motion—compensated picture signal interpolation”, U.S. Pat. No. 5,495,300, Inventors: G. de Haan, P. Biezen, A. Ojo, and H. Huijgen.
G. de Haan, P. Biezen, H. Huijgen, and O. Ojo, “True motion estimation with 3-D recursive search block-matching,”
IEEE Transactions on Circuits and Systems for Video Technology, vol.
3, No. 5, October 1993, pp. 368-388.
G. de Haan, P.W.A.C. Biezen, H. Huijgen and O. A. Ojo, “Graceful Degradation in Motion-Compensated Field-Rate Conversion” in
Proceedings of the International Workshop on HDTV
, Ottawa, Canada, 1993, pages 249-256.
JP 06-46358, 18.2.1994, “Liquid Crystal Driving Device”, Masao Kawamura. (Moving image emphasis system).
WO 96/35294, “Motion Compensated Filtering”, 7 Nov. 1996, Timothy Borer (Motion compensated filtering of interlace video). See also U.S. Pat. Nos. 5,335,194; 4,862,266; and 4,862,267;
SUMMARY OF THE INVENTION
The present inventors have therefore determined that the perceived artifacts evident in a color sequential display producing an image of a moving object may be addressed by separately motion compensating the objects represented within the respective color planes based on the time of display. This compensation scheme determines motion vectors for areas or objects within an image stream, predicts (e.g., by interpolating or extrapolating) the object position for respective times of presentation of respective color subframes, and sequentially displays the respective color planes representing the areas or objects at the predicted position.
Artifacts may be evident any time a dynamic pixel image is displayed at a time other than the theoretical timing of presentation. Thus, while the artifact is especially apparent in color sequential RGB displays driven using the nominal RGB color separation of a sequence of composite frames of a video signal, it may also occur in certain other instances, for example in systems employing other color plane definitions or color space representations. Therefore, it is understood that the invention is not limited to the modification of color plane images of RGB sequential color displays to correct for the non-coincidence of the actual time of display with the theoretical time of display with respect to the motion of objects within a frame. In fact, the invention encompasses the modification of image subframe data for display, especially where the image subframes represent different components of the image frame and are presented at different respective times than the nominal frame time, by reformulating the discrete time image subframes by distinguishing image object components having apparent independent motion, and resynthesizing an image subframe with a modified relationship object of the respective object components having independent motion. Preferably, this resynthesis is for the purpose of correcting a timing shift between the actual time of display of the image subframe including the object component and the theoretical time for display based on the original scene. The present invention also provides a system and method for calculating and presenting the image corrections with sub-pixel precision.
The prediction of object or area position may be of any known type, although interpolation or extrapolation of first order (velocity) is preferred. Higher order predictions, for example, require additional information, and may-therefore increase image presentation latency and/or memory requirements. While known motion estimation techniques, such as those employed in MPEG-2 encoders, may be employed, model based systems may also be employed, for example MPEG-4 or VRML-type systems, to define the object motion.
Motion estimation systems typically operate on image frames to analyze sequential changes. Where analogous regions are identifiable between sequential frames, typically confined to a search area, the displacement of the region may be encoded as a motion vector. Therefore, this information is often used in motion image compression, wherein the identification of an image block and its motion vector is transmitted, instead of the image block itself. According to the present invention, similar techniques may be used, as is well known in the art. However, portions of a moving foreground object may cover or uncover the background image. In the case of uncovering of background, the background image need be synthesized. In the case where an image i
Shimizu Jeffrey A.
Van Dijk Roy
LandOfFree
System and method for motion compensation of image planes in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for motion compensation of image planes in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for motion compensation of image planes in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3290612