Image coder-decoder using a matrix transform with weighted contribution of several points of the image to the formation of one point of the transform
First Claim
1. A matrix transform system for coding images with weighted contribution of several points of the image to each points of the coded image and for decoding coded images with weighted contribution of several points of the coded image to each point of the decoded image, said system comprising:
- a. means for sampling the lines of an image to be coded and forming with said image samples a square matrix associated with the image;
b. means for splitting said square matrix associated with the image into a plurality of first input component matrices of order 3N ×
3N having a central part of order N ×
N ;
c. means for multiplying each of said first input component matrices by a first rectangular coefficient matrix of order N ×
3N having a square central part in which the coefficients are equal to positive or negative unity and two square lateral parts in which the coefficients are selectively equal to zero and ±
α
where α
is a predetermined factor smaller than unity, and forming first intermediate matrices of order N ×
3d. means for multiplying each of said first intermediate matrices by a second rectangular coefficient matrix of order 3N ×
N which is the transpose of said first rectangular coefficient matrix, and forming first output matrices of order N ×
N, each of said first output matrices being the transform of the central part of a first input component matrix;
e. means for forming with said first output matrices a square matrix associated with the coded image;
f. means for splitting said square matrix associated with the coded image into a plurality of second input component matrices of order 3N ×
3N having a central part of order N ×
N;
g. means for multiplying each of said second input component matrices by a third rectangular coefficient matrix of order N ×
3N having a square central part in which the coefficients are equal to positive or negative unity and two square lateral parts in which the coefficients are selectively equal to zero and (a) ±
α
where α
is said predetermined factor smaller than unity and forming second intermediate matrices of order N ×
3N;
h. means for multiplying each of said second intermediate matrices by a fourth rectangular coefficient matrix of order 3N ×
N which is the transpose of said third rectangular coefficient matrix and forming second output matrices of order N ×
N, each of said second output matrices being the transform of the central part of a second input component matrix; and
i. means for forming with said second output matrices a square matrix associated with the decoded image.
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Abstract
A matrix transform system for coding and decoding images. The system comprises means for sampling the lines and the columns of an image and forming with these samples a sample square matrix and storing the same. This sample square matrix is split into component square matrices of order 3N × 3N having a central part of order N × N. Each of these component matrices is multiplied by a first rectangular coefficient matrix of order N × 3N having a square central part in which the coefficients are equal to unity and two square lateral parts in which the coefficients are selectively equal to zero and a predetermined factor smaller than unity, which gives an intermediate matrix of order N × 3N. This intermediate matrix is multiplied by a second rectangular coefficient matrix of order 3N × N which is the transpose of the first rectangular coefficient matrix, which gives an output matrix of order N × N which is the transform of the central part of the component matrix. If N = 2, the output matrix is of order 2 × 2; one of its terms depends on four samples of the image, two of its terms depend on 12 samples of the image and the last of its terms depends on 36 samples of the image.
34 Citations
5 Claims
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1. A matrix transform system for coding images with weighted contribution of several points of the image to each points of the coded image and for decoding coded images with weighted contribution of several points of the coded image to each point of the decoded image, said system comprising:
-
a. means for sampling the lines of an image to be coded and forming with said image samples a square matrix associated with the image; b. means for splitting said square matrix associated with the image into a plurality of first input component matrices of order 3N ×
3N having a central part of order N ×
N ;c. means for multiplying each of said first input component matrices by a first rectangular coefficient matrix of order N ×
3N having a square central part in which the coefficients are equal to positive or negative unity and two square lateral parts in which the coefficients are selectively equal to zero and ±
α
where α
is a predetermined factor smaller than unity, and forming first intermediate matrices of order N ×
3d. means for multiplying each of said first intermediate matrices by a second rectangular coefficient matrix of order 3N ×
N which is the transpose of said first rectangular coefficient matrix, and forming first output matrices of order N ×
N, each of said first output matrices being the transform of the central part of a first input component matrix;e. means for forming with said first output matrices a square matrix associated with the coded image; f. means for splitting said square matrix associated with the coded image into a plurality of second input component matrices of order 3N ×
3N having a central part of order N ×
N;g. means for multiplying each of said second input component matrices by a third rectangular coefficient matrix of order N ×
3N having a square central part in which the coefficients are equal to positive or negative unity and two square lateral parts in which the coefficients are selectively equal to zero and (a) ±
α
where α
is said predetermined factor smaller than unity and forming second intermediate matrices of order N ×
3N;h. means for multiplying each of said second intermediate matrices by a fourth rectangular coefficient matrix of order 3N ×
N which is the transpose of said third rectangular coefficient matrix and forming second output matrices of order N ×
N, each of said second output matrices being the transform of the central part of a second input component matrix; andi. means for forming with said second output matrices a square matrix associated with the decoded image. - View Dependent Claims (2, 3, 4, 5)
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Specification