Motion estimation and encoding of video signals in the transform domain
First Claim
Patent Images
1. A method of encoding a video signal including a series of samples representing the intensities of elements of a picture, including the steps of:
- (a) linearly transforming the intensity values for a first block of picture elements (pels) to a corresponding set of coefficient values,(b) predicting the values of said coefficients, and(c) encoding an error signal indicative of the difference between ones of said coefficient values and the predicted values thereof,wherein said predicting step is CHARACTERIZED BY(d) estimating the displacement of objects in said picture between a previous frame and the present frame, and(e) predicting said values using the coefficients of a second block of pels in said previous frame which is displaced from said first block by said estimate.
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Abstract
Video signals are encoded (FIG. 5) using motion compensated prediction which operates on a transform domain representation of the signal. The displacement estimate used for compensation is recursively updated, so that a feedback path exists between the output (205) of the displacement calculator and one of its output (209). The update term is also computed in the transform domain. A decoder (FIG. 6) uses the same prediction technique to recover the original picture.
80 Citations
22 Claims
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1. A method of encoding a video signal including a series of samples representing the intensities of elements of a picture, including the steps of:
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(a) linearly transforming the intensity values for a first block of picture elements (pels) to a corresponding set of coefficient values, (b) predicting the values of said coefficients, and (c) encoding an error signal indicative of the difference between ones of said coefficient values and the predicted values thereof, wherein said predicting step is CHARACTERIZED BY (d) estimating the displacement of objects in said picture between a previous frame and the present frame, and (e) predicting said values using the coefficients of a second block of pels in said previous frame which is displaced from said first block by said estimate. - View Dependent Claims (2, 3, 4)
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5. A method of encoding a series of intensity values each representing an element of a picture, comprising the steps of:
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(a) transforming the intensity values for a block of pels to a series of coefficients representative thereof, (b) predicting the value of said coefficients based upon the value of coefficients for a block of pels in a previous frame of said picture, and (c) encoding a prediction error signal representing the difference between the actual and predicted values of ones of said coefficients, wherein said predicting step is CHARACTERIZED BY (d) selecting said block of pels in said previous frame in accordance with an estimate of the displacement of objects in said picture occurring between said previous frame and the present frame. - View Dependent Claims (6, 7, 8, 9)
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10. A method of encoding a video signal which includes a series of samples each indicating the intensity of an element of a picture, including the steps of:
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(1) converting the intensity values for a first block of pels to a series of coefficient values through a linear transformation, (2) predicting the values of each of said coefficients based upon stored intensity values for elements in a previous frame of said picture, and (3) encoding said signal as a function of the difference between predicted and actual coefficient values, CHARACTERIZED BY (4) estimating the displacement of objects in said picture occurring in the period between said prior frame and the present frame, and (5) selecting stored values for a second block of pels for said prediction based upon said displacement estimate. - View Dependent Claims (11)
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12. A method of encoding a video signal which includes a series of samples each indicating the intensity of an element of a picture, including the steps of:
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(1) converting the intensity values for a first block of pels to a series of coefficient values through a linear transformation. (2) predicting the values of each of said coefficients based upon stored intensity values for elements in a previous frame of said picture, and (3) encoding said signal as a function of the difference between predicted and actual coefficient values, CHARACTERIZED BY (4) estimating the displacement of objects in said picture occurring in the period between said prior frame and the present frame, said estimating step including updating each estimate each time said signal is encoded, as a function of the prior estimate, and (5) selecting stored values for said prediction based upon said displacement estimate, said selecting step including interpolating coefficient values derived from said previous frame to yield the coefficient values for a second block of pels displaced from said first block by said displacement estimate. - View Dependent Claims (13, 14)
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15. Apparatus for encoding a series of intensity values each representing an element of a picture, comprising:
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(a) means (101) transforming the intensity values for a block of pels to a series of coefficients representative thereof, (b) means (200) for predicting the value of said coefficients based upon the value of coefficients for a block of pels in a previous frame of said picture, and (c) means (103) for encoding a prediction error signal representing the difference between the actual and predicted values of ones of said coefficients, wherein said predicting means is CHARACTERIZED BY (d) means (203,
210) for selecting said block of pels in said previous frame in accordance with an estimate of the displacement of objects in said picture occurring between said previous frame and the present frame. - View Dependent Claims (16, 17)
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18. Apparatus for encoding a video signal which includes a series of samples each indicating the intensity of an element of a picture, including:
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(1) means (101) for converting the intensity values for a first block of pels to a series of coefficient values through a linear transformation, (2) means (200) for predicting the values of each of said coefficients based upon stored intensity values for elements in a previous frame of said picture, and (3) means (103) for encoding said signal as a function of the difference between predicted and actual coefficient values, CHARACTERIZED BY (4) means (210) for estimating the displacement of objects in said picture occurring in the period between said prior frame and the present frame, and (5) means (203) for selecting stored values for a second block of pels for said prediction based upon said displacement estimate. - View Dependent Claims (19)
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20. Apparatus for encoding a video signal which includes a series of samples each indicating the intensity of an element of a picture, including:
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(1) means (101) for converting the intensity values for a first block of pels to a series of coefficient values through a linear transformation, (2) means (200) for predicting the values of each of said coefficients based upon stored intensity values for elements in a previous frame of said picture, and (3) means (103) for encoding said signal as a function of the difference between predicted and actual coefficient values, CHARACTERIZED BY (4) means (210) for estimating the displacement of objects in said picture occurring in the period between said prior frame and the present frame, wherein said estimating means includes means (208) for updating each estimate, each time said signal is encoded, as a function of the prior estimate, and (5) means (203) for selecting stored values for said prediction based upon said displacement estimate, wherein said selecting means includes means (536) for interpolating coefficient values derived from said previous frame to yield coefficient values for a second block of pels displaced from said first block by said displacement estimate. - View Dependent Claims (21, 22)
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Specification