Patent ID: 6212235
Filing Date: 2001-04-03
Classification: G06T,H04N

Abstract:
Encoder for performing motion compensated encoding of video data, comprising:motion field estimating means, having an input for receiving a first video data frame I.sub.n and a reference frame R.sub.ref, said motion field estimating means being arranged to estimate a motion vector field describing scene motion displacements of video frame pixels;motion field encoding means having an input to receive from said motion field estimating means said estimated motion vector field; partitioning information indicating partitioning of a video frame into at least two segments said segments being a first segment S.sub.i and a second segment S.sub.j ; said motion field encoding means being arranged to obtain compressed motion information comprising first motion coefficients representing said motion vector field;motion compensated prediction means for predicting a predicted video data frame based on said reference frame R.sub.ref and said compressed motion information;computing means having an input for receiving said first video data frame and said predicted video data frame, said computing means being arranged to calculate a prediction error frame based on said predicted video data frame and on said first video data frame;prediction error encoding means for encoding said prediction error frame;wherein said motion encoding means further comprises:means for calculating for each segment a distortion matrix E and a distortion vector y such that a predefined measure .DELTA.E for distortion in each segment, due to approximating said motion vector field as coefficients c.sub.i of a set of polynomial basis function f.sub.i, is a function of (Ec-y), c being a vector of said motion coefficients c.sub.i ;means for decomposing said distortion matrix E into a first matrix Q and a second matrix R such thatdet Q.noteq.0 andQ R=E,a subset of the set of all columns of matrix Q being a basis of a vector space defined by all possible linear combinations of all column vectors of matrix E, columns of matrix Q being orthogonal to each other;means for calculating an auxiliary vector z according to z=Q.sup.-1 y, Q.sup.-1 being the inverse matrix of said first matrix Q;means for generating for each segment a column extended matrix A comprising the columns of matrix R and vector z as an additional column, and for selecting all rows of matrix A which have elements unequal to zero in all columns due to matrix R;means for merging segments based on selective combination of segments producing an increase in said prediction error within a certain limit;means for generating a row extended matrix B comprising said selected rows of matrix A of said first segment S.sub.i and said selected rows of matrix A of said second segment S.sub.j ;means for performing a series of multiplications of rows of matrix B with scalars unequal to zero and additions of rows of matrix B in order to obtain a modified matrix B' having in the columns due to matrix R as many rows as possible filled with zeros;orthogonalising means receiving one of said matrices A, B and B' as an input matrix M, said orthogonalising means being arranged to replace said polynomial basis functions f.sub.i by orthogonal basis functions f.sub.i and to calculate second motion coefficients c using said orthogonal basis functions and said input matrix M; andquantisation means for quantising said second coefficients c.