Motion-adaptive modelling of scene content for very low bit rate model-assisted coding of video sequences
First Claim
1. A method of coding a video signal, the video signal comprising a succession of frames, a given one of the frames comprising an image including a foreground portion and a background portion, the foreground portion of the image of the given frame including a predetermined object, the method comprising the steps of:
- automatically determining the foreground portion of the image of the given frame;
automatically determining a region of interest within the foreground portion of the image of the given frame, said region of interest including at least a portion of the predetermined object, by matching one or more predetermined shapes to the predetermined object in the foreground portion of the image of the given frame;
coding the determined region of interest with a first coder, the first coder having a first coding error; and
coding at least a portion of the image of the given frame, which portion excludes the determined region of interest, with a second coder, the second coder having a second coding error, wherein said first coding error is smaller than said second coding error.
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Accused Products
Abstract
A method and apparatus for video coding whereby a region of an image which includes a predetermined object such as a person'"'"'s face in the foreground portion of the image is automatically determined. Specifically, the foreground portion of the image is identified, and one or more predetermined (geometric) shapes (e.g., ellipses) are compared with the shapes of objects found in the foreground portion of the image. The foreground portion of an image may be determined by performing a global motion estimation of the overall image to detect global image movement resulting, for example, from camera pan and zoom. That portion of the image whose movement is consistent with the estimated global motion may be identified as the background portion, with the remainder of the image identified as the foreground portion. The identified region of the image which includes the predetermined object and portions of the image which do not include the predetermined object may be coded with differing levels of coding accuracy (e.g., using different quantization levels), such that if the identified region contains, for example, a person'"'"'s face, the quality of the coding of the face may be improved relative to the quality of the coding of other portions of the image.
322 Citations
20 Claims
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1. A method of coding a video signal, the video signal comprising a succession of frames, a given one of the frames comprising an image including a foreground portion and a background portion, the foreground portion of the image of the given frame including a predetermined object, the method comprising the steps of:
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automatically determining the foreground portion of the image of the given frame; automatically determining a region of interest within the foreground portion of the image of the given frame, said region of interest including at least a portion of the predetermined object, by matching one or more predetermined shapes to the predetermined object in the foreground portion of the image of the given frame; coding the determined region of interest with a first coder, the first coder having a first coding error; and coding at least a portion of the image of the given frame, which portion excludes the determined region of interest, with a second coder, the second coder having a second coding error, wherein said first coding error is smaller than said second coding error. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A video coder for coding a video signal, the video signal comprising a succession of frames, a given one of the frames comprising an image including a foreground portion and a background portion, the foreground portion of the image of the given frame including a predetermined object, the apparatus comprising:
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means for automatically determining the foreground portion of the image of the given frame; means for automatically determining a region of interest within the foreground portion of the image of the given frame, said region of interest including at least a portion of the predetermined object, by matching one or more predetermined shapes to the predetermined object in the foreground portion of the image of the given frame; a first coder for coding the determined region of interest, the first coder having a first coding error; and a second coder for coding at least a portion of the image of the given frame, which portion excludes the determined region of interest, the second coder having a second coding error, wherein said first coding error is smaller than said second coding error. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification