Method and arrangement for redundancy-reducing picture coding
First Claim
1. A method of redundancy-reducing coding of the values of picture elements of pictures which are scanned line-by-line and which are distributed in a matrix as lines and picture elements, a difference value being formed for substantially each picture element, said difference value being the difference between the actual value of the picture element and a predictive value obtained from the values of other picture elements, comprising the steps of:
- dividing the picture matrix into adjacent, equally large, square sub-pictures;
intermediate storing the values of the picture elements of the picture lines which are covered by a series of sub-pictures;
obtaining the predictive value for a picture element from the values of the other picture elements of the associated sub-picture; and
quantizing the resulting first difference values.
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Accused Products
Abstract
With known methods for predictive decorrelation this decorrelation only applies to one or more previously scanned elements of the same picture line. In accordance with the invention a picture to be scanned is divided into sub-pictures wherein a number of picture lines equal to the number of lines comprised in a sub-picture is intermediately stored in shift registers, a processing circuit being connected to the last stages of these shift registers, which processing circuit multiplies the values of the picture elements of one sub-picture with the same number of coefficients stored in the processing device and which adds the products. In a preferred embodiment the difference values obtained in this manner are also decorrelated in a second stage, the matrix of the difference values being divided into difference value sub-pictures which are shifted, preferably diagonally, relative to the original sub-pictures. A considerably larger surrounding area of each picture element is thus involved in the prediction.
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Citations
11 Claims
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1. A method of redundancy-reducing coding of the values of picture elements of pictures which are scanned line-by-line and which are distributed in a matrix as lines and picture elements, a difference value being formed for substantially each picture element, said difference value being the difference between the actual value of the picture element and a predictive value obtained from the values of other picture elements, comprising the steps of:
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dividing the picture matrix into adjacent, equally large, square sub-pictures; intermediate storing the values of the picture elements of the picture lines which are covered by a series of sub-pictures; obtaining the predictive value for a picture element from the values of the other picture elements of the associated sub-picture; and quantizing the resulting first difference values. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A digital circuit for redundancy-reducing coding of the values of picture elements of pictures which are scanned line-by-line and which are distributed in a matrix as lines and picture elements, a difference value being formed for substantially each picture element, said difference value being the difference between the actual value of the picture element and a predictive value obtained from the values of other picture elements, comprising:
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at least a number of picture element shift registers means corresponding to the number of lines of the given sub-picture size, each having a capacity of the picture elements of a picture line, which cyclically and successively store the signals of the picture elements of the picture line-by-line; a first processing means for obtaining the difference values connected to the number of the last elements of the picture element shift register means which number is equal to the number of lines; and
whereinafter all difference values of each sub-picture have been produced, a clock-pulse control device supplies to the picture element shift register means a number of shift clock pulses equal to the number of lines of the sub-pictures. - View Dependent Claims (8, 9, 10, 11)
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Specification