Patent ID: 7454084
Filing Date: 2008-11-18
Classification: G06F,H04N

Abstract:
1. A method of transforming a digital image signal using a factored linear transformation matrix, wherein the method includes generating matrix factors for a finite-dimensional linear transform using a computer, each matrix factor represented by a symbol, the finite-dimensional linear transform represented by data values stored in a linear transformation matrix A having a nonzero determinant, the method comprising: applying a first LU-decomposition to the linear transformation matrix generating four matrices from the LU-decomposition of the linear transformation matrix generating a third matrix represented by the symbol Â from the linear transformation matrix A, the third matrix having a plurality of rows and a determinant of 1; computing a signed permutation matrix Π from the linear transformation matrix generating a permuted linear transformation matrix represented by the symbol A′ from the linear transformation matrix, the permuted linear transformation computing a second upper triangular matrix represented by the symbol U factoring the permuted linear transformation generating the matrix factors for the linear transformation matrix A, the matrix factors including at least the lower triangular matrix L, the upper triangular matrix U, the second upper triangular matrix U transforming the digital image signal by applying the linear transform to the digital signal using the matrix factors generated by the computer.