Three dimensional motion compensated video coding
AssigneeAT&T Bell Laboratories
InventorAtul Puri
Life of this patent
Estimating the term…
Abstract
A video signal encoder uses three dimensional transform coding on blocks of intensity values and then selects the most significant coefficients for further processing by separating the coefficients into several groups have approximately the same energy and thus approximately the same significance. The intensity values can be error values computed by forming the difference between the actual intensity values and values computed using conditional motion compensated interpolation or motion compensated prediction. The encoder can use both two dimensional and three dimensional transformations, and if desired, adaptively switch between those processing techniques. A complementary decoder recovers the intensity values from encoded signals.
Claims21
A method of encoding a signal representing the actual intensity values of picture elements (pels) in a series of frames, comprising the steps of
- (i) computing estimates of the values of pels in at least two intermediate frames which lie between reference frames, based on the values of pels in at least one of said reference frames;
- (ii) combining error values for corresponding blocks of pels in each of said intermediate frames to form a series of transform coefficients representing said error values, each of said error values representing the difference between said estimated value and said actual value of said pel, and
- (iii) selecting ones of said coefficients for further processing based upon the significance of information represented by said coefficients,
- wherein said selection step includes
- (a) grouping said coefficients into a plurality of groups each containing coefficients having approximately the same significance, and
- (b) selecting all coefficients from only selected ones of said groups.
A method of encoding a video signal representing the actual intensity values of picture elements (pels) in a series of frames, comprising the steps of
- (i) computing estimates of the intensity values of pels in at least two intermediate frames which lie between reference frames, based on the intensity values of pels in at least one of said reference frames;
- (ii) combining error values for corresponding blocks of pels in each of said intermediate frames to form a series of transform coefficients representing said error values, each of said error values representing the difference between said estimated intensity value and said actual intensity value of said pel,
- (iii) selecting ones of said coefficients for further processing based upon selected characteristics of said coefficients, and
- (iv) encoding said selected coefficients to produce a representation of said video signal,
- wherein said intensity estimiate computing step includes
- (a) forming estimates of the motion of objects in said frames, and
- (b) calculating said intensity estimates as a function of said motion estimates.
A method of encoding a signal representing the intensity values of picture elements (pels) in a series of frames, comprising the steps of computing error values s(m,n,p) for three dimensional blocks of pels, said 3D blocks including M.times.N pels in each of P of said frames;
- forming M.times.N.times.P discrete cosine transformation coefficients c(j,k,l) for each of said 3D blocks of error values;
- grouping said coefficients into S groups, each of said groups containing coefficients having approximately the same energy, and
- selecting coefficients only from ones of said groups to represent said signal.
Apparatus for encoding a signal representing the actual intensity values of picture elements (pels) in a series of frames, comprising
- (i) means for computing estimates of the values of pels in at least two intermediate frames which lie between reference frames, based on the values of pels in at least one of said reference frames;
- (ii) means for combining error values for corresponding blocks of pels in each of said intermediate frames to form a series of transform coefficients representing said error values, each of said error values representing the difference between said estimated value and said actual value of said pel, and
- (iii) means for selecting one of said coefficients for further processing based upon the significance of information represented by said coefficients,
- wherein said selection means includes means for grouping said coefficients into a plurality of groups each containing coefficients having approximately the same significance and for selecting all coefficients from only selected ones of said groups.
Apparatus (FIG. 2) for encoding a video signal representing the actual intensity values of picture elements (pels) in a series of frames, comprising
- (i) means (210-228) for computing estimates of the intensity values of pels in at least two intermediate frames which lie between reference frames, based on the intensity values of pels in at least of said reference frames;
- (ii) means (205) for combining error values for corresponding blocks of pels in each of said intermediate frames to form a series of transform coefficients representing said error values, each of said error values representing the difference between said estimated intensity value and said actual intensity value of said pel,
- (iii) means (207) for selecting ones of said coefficients for further processing based upon selected characteristics of said coefficients, and
- (iv) means (208) for encoding said selected coefficients to produce a representation of said video signal,
- wherein said intensity estimate computing means includes
- (a) means (228) for forming estimates of the motion of objects in said frames, and
- (b) means (215 and 217) for calculating said intensity estimates as a function of said motion estimates.
Apparatus for encoding a signal representing the intensity values of picture elements (pels) in a series of frames, comprising
- means for computing error values s(m,n,p) for three dimensional blocks of pels, said 3D blocks including M.times.N pels in each of P of said frames;
- means for forming M.times.N.times.P discrete cosine transformation coefficients c(j,k,l) for each of said 3D blocks of error values;
- and
- means for grouping said coefficients into S groups, each of said groups containing coefficients having approximately the same energy and selecting coefficients only from ones of said groups to represent said signal.
A method of encoding a video signal representing the acutal intensity values of picture elements (pels) in a series of frames, comprising the steps of
- (i) computing estimates of the intensity values of pels in at least two intermediate frames which lie between reference frames, based on the intensity values of pels in said reference frames and on motion of objects in said frames;
- (ii) combining error values for blocks of pels to form a series of transform coefficients representing said error values, each of said error values representing the difference between said estimated intensity value and said actual intensity value of said pel,
- (iii) selecting ones of said coefficients for further processing based upon selected characteristics of said coefficients, and
- (iv) encoding said selected coefficients to produce a representation of said video signal,
- wherein said combining step includes:
- (a) calculating DCT coefficients for two dimensional blocks of M.times.N pels per some blocks of said frames;
- and
- (b) calculating DCT coefficients for three dimensional blocks of M.times.N pels in corresponding locations in each of P frames for other blocks of said frames.
Dependencies are inferred from the claim text.