Method of image signal encoding by orthogonal transformation

Claim 1

A method of image signal encoding by orthogonal transformation, which comprises the steps of: (i) dividing two-dimensional image signals into blocks and conducting two-dimensional orthogonal transformation on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, (ii) recognizing a region, where absolute values of almost all of the transformed signals obtained by the orthogonal transformation are smaller than a predetermined value, from a matrix of the transformed signals put side by side in order of sequence of said orthogonal function in longitudinal and transverse directions in the block, and (iii) sampling only the transformed signals outside of said recognized region, and encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 2

A method of image signal encoding by orthogonal transformation, which comprises the steps of: (i) dividing two-dimensional image signals into blocks and conducting two-dimensional orthogonal transformation on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, (ii) recognizing a region, where absolute values of almost all of the transformed signals obtained by the orthogonal transformation are smaller than a predetermined value, from a matrix of the transformed signals put side by side in order of sequence of said orthogonal function in longitudinal and transverse directions in the block, and (iii) sampling only the transformed signals outside of said recognized region, and encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 3

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequency of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic value corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) sampling in each block only the transformed signals on a frequency side lower than a frequency corresponding to the transformed signal at which the use obtained by said addition comes up to a predetermined value, and (iii) encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 4

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequency of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic value corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) sampling in each block only the transformed signals on a frequency side lower than a frequency corresponding to the transformed signal at which the use obtained by said addition comes up to a predetermined value, and (iii) encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 12

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) sampling in each block only the transformed signals on a frequency side lower than (a) a frequency corresponding to the transformed signal at which the sum obtain by said addition comes up to a predetermined value, or (b) a critical frequency specified in advance, whichever higher, and (iii) encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 13

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) sampling in each block only the transformed signals on a frequency side lower than (a) a frequency corresponding to the transformed signal at which the sum obtain by said addition comes up to a predetermined value, or (b) a critical frequency specified in advance, whichever higher, and (iii) encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 14

A method of image signal encoding by orthogonal transformation wherein two dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) sampling in each block only the transformed signals on a frequency side lower that a frequency corresponding to the transformed signal at which the use obtained by said addition comes up to a predetermined value, (iii) encoding the sampled transformed signals respectively with an intrinsic code length, and (iv) correcting the sampling regions in the blocks adjacent to each other so that the difference between said sampling regions becomes not larger than a predetermined value when said difference is larger than said predetermined value.

Claim 15

A method of image signal encoding by orthogonal transformation wherein two dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) sampling in each block only the transformed signals on a frequency side lower that a frequency corresponding to the transformed signal at which the use obtained by said addition comes up to a predetermined value, (iii) encoding the sampled transformed signals respectively with an intrinsic code length, and (iv) correcting the sampling regions in the blocks adjacent to each other so that the difference between said sampling regions becomes not larger than a predetermined value when said difference is larger than said predetermined value.

Claim 16

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) comparing in each block a frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up a predetermined value, with a critical frequency specified in advance, (iii) sampling only the transformed signals on a frequency side lower than said critical frequency in the case where said frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to the predetermined value, higher than said critical frequency, and sampling only the transformed signals on a frequency side lower than said signal, at which the sum obtained by said addition comes up to the predetermined value, in the case where said frequency corresponding to said transformed signal is not higher than said critical frequency, and (iv) encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 17

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side toward a low frequency component side, (ii) comparing in each block a frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up a predetermined value, with a critical frequency specified in advance, (iii) sampling only the transformed signals on a frequency side lower than said critical frequency in the case where said frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to the predetermined value, higher than said critical frequency, and sampling only the transformed signals on a frequency side lower than said signal, at which the sum obtained by said addition comes up to the predetermined value, in the case where said frequency corresponding to said transformed signal is not higher than said critical frequency, and (iv) encoding the sampled transformed signals respectively with an intrinsic code length.

Claim 25

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side towards a low frequency component side, (ii) comparing in each block a frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to a predetermined value, with a critical frequency specified in advance, (iii) sampling only transformed signals on a frequency side lower than said critical frequency in the case where said frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to the predetermined value, is higher than said critical frequency, and sampling only the transformed signals on a frequency side lower than said frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to a predetermined value, in the case where said frequency corresponding to said transformed signal is not higher than said critical frequency, (iv) encoding the sampled transformed signals respectively with an intrinsic code length, and (v) correcting the sampling regions in the blocks adjacent to each other so that the difference between said sampling regions becomes not larger than a predetermined value when said difference is larger than said predetermined value.

Claim 26

A method of image signal encoding by orthogonal transformation wherein two-dimensional image signals are divided into blocks, orthogonal transformation is conducted on each block of two-dimensional image signals on the basis of a predetermined orthogonal function, and transformed signals obtained by the orthogonal transformation and put side by side in the order of sequence of said orthogonal function in the block are respectively encoded with an intrinsic code length, wherein the improvement comprises the steps of: (i) adding characteristic values corresponding to absolute values of the respective transformed signals in said block sequentially from a high frequency component side towards a low frequency component side, (ii) comparing in each block a frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to a predetermined value, with a critical frequency specified in advance, (iii) sampling only transformed signals on a frequency side lower than said critical frequency in the case where said frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to the predetermined value, is higher than said critical frequency, and sampling only the transformed signals on a frequency side lower than said frequency corresponding to the transformed signal, at which the sum obtained by said addition comes up to a predetermined value, in the case where said frequency corresponding to said transformed signal is not higher than said critical frequency, (iv) encoding the sampled transformed signals respectively with an intrinsic code length, and (v) correcting the sampling regions in the blocks adjacent to each other so that the difference between said sampling regions becomes not larger than a predetermined value when said difference is larger than said predetermined value.