Moving image signal coding system

Claim 1

A system for coding moving image signals using a predictive error signal produced by predictive coding base on inter-frame correlation, comprising: orthogonal transformation means for transforming orthogonally the predictive error signal to generate a transformed error signal; quantization means for quantizing the transformed error signal for each block of a picture frame constituted by N lines of M pixels; and block coding/non-coding decision means for calculating a first evaluation value of the predictive error signal for each block of the picture frame, for deciding that block non-coding is applicable when the first evaluation value is less than a first threshold value, for deciding that block coding is applicable when the first evaluation value Sm is greater than the first threshold value, for preventing quantization of the transformed error signal when block non-coding is applicable, and for permitting quantization of the transformed error signal when block coding is applicable, said block coding/non-coding decision means dividing each block into a plurality of sub-blocks having a size smaller than the block, calculating a sub-block evaluation value for each sub-block, comparing the sub-block evaluation value with a sub-block threshold value, and deciding that the block in question is to be coded when at least one coding sub-block exists and otherwise deciding that the block in question is not to be coded.

Claim 2

A system for coding moving image signals using a predictive error signal produced by predictive coding base on inter-frame correlation, comprising: orthogonal transformation means for transforming orthogonally the predictive error signal to generate a transformed error signal; quantization means for quantizing the transformed error signal for each block of a picture frame constituted by N lines of M pixels; and block coding/non-coding decision means for calculating a first evaluation value of the predictive error signal for each block of the picture frame, for deciding that block non-coding is applicable when the first evaluation value is less than a first threshold value, for deciding that block coding is applicable when the first evaluation value Sm is greater than the first threshold value, for preventing quantization of the transformed error signal when block non-coding is applicable, and for permitting quantization of the transformed error signal when block coding is applicable, said block coding/non-coding decision means dividing each block into a plurality of sub-blocks having a size smaller than the block, calculating a sub-block evaluation value for each sub-block, comparing the sub-block evaluation value with a sub-block threshold value, and deciding that the block in question is to be coded when at least one coding sub-block exists and otherwise deciding that the block in question is not to be coded.

Claim 4

A system for coding moving image signals using a predictive error signal produced by predictive coding based on inter-frame correlation between a present input picture signal and a stored picture signal, comprising: quantization means for quantizing a signal for each block of a picture frame constituted by N lines of M pixels; and inter-frame/intra-frame selection means for calculating a first evaluation value Sm of the predictive error signal for each block of the picture frame and a second evaluation value Si, for comparing the calculated first (Sm) and second (Si) evaluation values, and for supplying to said quantization means the predictive error signal when Sm<T 2 , where T 2 is a first threshold value and when Sm<Si, and otherwise supplying to said quantization means the present input picture signal.

Claim 5

A system for coding moving image signals using a predictive error signal produced by predictive coding based on inter-frame correlation between a present input picture signal and a stored picture signal, comprising: quantization means for quantizing a signal for each block of a picture frame constituted by N lines of M pixels; and inter-frame/intra-frame selection means for calculating a first evaluation value Sm of the predictive error signal for each block of the picture frame and a second evaluation value Si, for comparing the calculated first (Sm) and second (Si) evaluation values, and for supplying to said quantization means the predictive error signal when Sm<T 2 , where T 2 is a first threshold value and when Sm<Si, and otherwise supplying to said quantization means the present input picture signal.

Claim 9

A system for coding moving image signals using a predictive error signal produced by a predictive coding based on inter-frame correlation between a present input picture signal and a stored picture signal, and quantization means for quantizing the predictive error signal for each block of a picture frame constituted by N lines of M pixels, said system comprising: block coding/non-coding decision means for calculating a first evaluation value Sm of the predictive error signal for each block of the picture frame, for deciding that block non-coding is applicable when the first evaluation value Sm is less than a predetermined first threshold value T 1 , and for deciding that block coding is applicable when the first evaluation value Sm is greater than the first threshold value T 1 ; inter-frame/intra-frame selection means for calculating a second evaluation signal a Si representing evaluation of each block with regard to the input picture signal, for comparing the first (Sm) and second (Si) evaluation values, and for selecting the predictive error signal when Sm<T 2 , where T 2 is a second threshold value, Sm≦Si, and selecting the present input picture signal in other cases; and means for preventing transmission of the predicted error signal when said block coding/non-coding decision means decides that block non-coding is applicable and said inter-frame/intra-frame selection means selects the present input picture signal and for transmitting the predicted error signal when said block coding/non-coding decision means decides that block coding is applicable and said inter-frame/intra-frame selection means selects the predictive error signal.

Claim 10

A system for coding moving image signals using a predictive error signal produced by a predictive coding based on inter-frame correlation between a present input picture signal and a stored picture signal, and quantization means for quantizing the predictive error signal for each block of a picture frame constituted by N lines of M pixels, said system comprising: block coding/non-coding decision means for calculating a first evaluation value Sm of the predictive error signal for each block of the picture frame, for deciding that block non-coding is applicable when the first evaluation value Sm is less than a predetermined first threshold value T 1 , and for deciding that block coding is applicable when the first evaluation value Sm is greater than the first threshold value T 1 ; inter-frame/intra-frame selection means for calculating a second evaluation signal a Si representing evaluation of each block with regard to the input picture signal, for comparing the first (Sm) and second (Si) evaluation values, and for selecting the predictive error signal when Sm<T 2 , where T 2 is a second threshold value, Sm≦Si, and selecting the present input picture signal in other cases; and means for preventing transmission of the predicted error signal when said block coding/non-coding decision means decides that block non-coding is applicable and said inter-frame/intra-frame selection means selects the present input picture signal and for transmitting the predicted error signal when said block coding/non-coding decision means decides that block coding is applicable and said inter-frame/intra-frame selection means selects the predictive error signal.