Picture signal digital processing unit

A digital picture encoding apparatus for a picture signal, said apparatus comprising:

• digital data compressing means for dividing a picture signal into blocks and for generating compressed picture data corresponding to said picture signal blocks, including orthogonal transformer means for generating frequency components of picture signal blocks of said picture signal, and variable-length encoding means for encoding said frequency components to provide variable-length compressed picture data;
• and
• error correction encoding means for (a) arranging compressed picture data from said digital data compressing means into two-dimensional arrays of error blocks, each code block having M word columns and L word rows, where M and L are integers, each block including (1) compressed picture data, (2) an inner check code for each word row, and (3) an outer check code for each word column, and for (b) providing inner codes each composed of (1) a row of said compressed picture data arranged into said two-dimensional error correction code blocks, (2) said inner check code, (3) a synchronizing code at each head of a row of said error correction code blocks, and (4) an inner header code of information indicating a relationship between data of the main part of said inner code and a display position of said data on a display screen;
• wherein:
• the M words forming a row of said two-dimensional array of error correction code blocks have a data length equal to or larger than a mean code length of said variable-length compressed picture data in at least one of said picture signal blocks,
• said digital data compressing means further includes fixed-length encoding means for encoding a DC component of the picture signal, and means for dividing said compressed picture data into first data, composed of fixed-length coded data encoded by said fixed-length encoding means and variable-length coded data representing lower frequency components, and second data composed of variable-length coded data representing higher frequency components, and
• said error correction encoding means includes means for inserting said first data of each block into one of said inner codes, so that the beginning of said first data coincides with a predetermined position in said inner code.

A digital picture encoding/decoding apparatus for compressed picture data, said apparatus comprising:

• an encoding section including:
• (a) digital data compressing means for dividing a picture signal into blocks and for generating compressed picture data corresponding to said picture signal blocks, including orthogonal transformer means for generating said compressed picture data by generating frequency components of said picture signal blocks, and variable-length encoding means for encoding said frequency components;
• and
• (b) error correction encoding means for (1) arranging said compressed picture data into two-dimensional arrays of error correction code blocks, each code block including compressed picture data having M word columns and L word rows, where M and L are integers, (2) providing an inner check code to each word row and an outer check code to each word column of said error correction code blocks, and (3) structuring inner codes each composed of (i) a row of said compressed picture data arranged into said two-dimensional error correction code blocks, (ii) said inner check code, (iii) a synchronizing code at each head of a row of said error correction code blocks, and (iv) an inner header code of information indicating a relationship between data of the main part of said inner code and a display position of said data on a display screen;
• wherein the M words forming a row of said two-dimensional array of error correction code blocks have a data length equal to or larger than a mean code length of said variable-length compressed picture data in at least one of said picture signal blocks;
• and
• a decoding section including:
• (a) error correction decoding means for correcting errors in compressed picture data received by said decoding means after compression by said digital data compressing means, by utilizing an inner check code and an outer check code, provided by said error correction encoding means and included in said received compressed picture data;
• and
• (b) digital data expanding means for expanding compressed picture data outputted from said error correction decoding means, including variable-length decoding means for decoding said compressed picture data into frequency components, and orthogonal inverse transformer means for generating a picture signal from said frequency components;
• said error correction decoding means including change-over means for selectively outputting either data resulting from error correction by way of said inner check code and outer check code or a signal resulting from error correction by way of only said inner check code.

A digital picture encoding/decoding apparatus for compressed picture data, said apparatus comprising:

• an encoding section including:
• (a) digital data compressing means for dividing a picture signal into blocks and for generating compressed picture data corresponding to said picture signal blocks, including orthogonal transformer means for generating said compressed picture data by generating frequency components of said picture signal blocks, and variable-length encoding means for encoding said frequency components;
• and
• (b) error correction encoding means for (1) arranging said compressed picture data into two-dimensional arrays of error correction code blocks, each code block having M word columns and L word rows, where M and L are integers, (2) providing an inner check code to each word row and an outer check code to each word column of said error correction code blocks, and (3) structuring inner codes each composed of (i) a row of said compressed picture data arranged into said two-dimensional error correction code blocks, (ii) said inner check code, (iii) a synchronizing code at each head of a row of said error correction code blocks, and (iv) an inner header code of information indicating a relationship between data of the main part of said inner code and a display position of said data on a display screen,
• wherein:
• the M words forming a row of said two-dimensional array of error correction code blocks have a data length equal to or larger than a mean code length of said variable-length compressed picture data in at least one of said picture signal blocks,
• said digital data compressing means further includes fixed-length encoding means for encoding a DC component of said picture signal obtained from said orthogonal transformer means, and for sending fixed-length coded data to said error correction encoding means, and
• said error correction encoding means includes means for applying said fixed-length coded data to a fixed data area of said inner code;
• and
• a decoding section including:
• (a) error correction decoding means for correcting errors in compressed picture data received by said decoding means after compression by said digital data compressing means, by utilizing an inner check code and an outer check code, provided by said error correction encoding means and included in said received compressed picture data;
• and
• (b) digital data expanding means for expanding compressed picture data outputted from said error correction decoding means, including variable-length decoding means for decoding said compressed picture data into frequency components, and orthogonal inverse transformer means for generating a picture signal from said frequency components,
• wherein:
• said error correction decoding means including change-over means for selectively outputting either data resulting from error correction by way of said inner check code and outer check code or a signal resulting from error correction by way of only said inner check code, and
• said digital data expanding means further includes fixed-length decoding means for decoding fixed-length coded data received by said error correction decoding means.

A digital picture encoding/decoding apparatus for compressed picture data, said apparatus comprising:

• an encoding section including:
• (a) digital data compressing means for dividing a picture signal into blocks and for generating compressed picture data corresponding to said picture signal blocks, including orthogonal transformer means for generating said compressed picture data by generating frequency components of said picture signal blocks, and variable-length encoding means for encoding said frequency components;
• and
• (b) error correction encoding means for (1) arranging said compressed picture data into two-dimensional arrays of error correction code blocks, each code block having M word columns and L word rows, where M and L are integers, (2) providing an inner check code to each word row and an outer check code to each word column of said error correction code blocks, and (3) structuring inner codes each composed of (i) a row of said compressed picture data arranged into said two-dimensional error correction code blocks, (ii) said inner check code, (iii) a synchronizing code at each head of a row of said error correction code blocks, and (iv) an inner header code of information indicating a relationship between data of the main part of said inner code and a display position of said data on a display screen,
• wherein:
• the M words forming a row of said two-dimensional array of error correction code blocks have a data length equal to or larger than a mean code length of said variable-length compressed picture data in at least one of said picture signal blocks,
• said digital data compressing means further includes fixed-length encoding means for encoding a DC component of the picture signal, and means for dividing said compressed picture data into first data, composed of fixed-length coded data encoded by said fixed-length encoding means and variable-length coded data representing lower frequency components, and second data, composed of variable-length coded data representing higher frequency components, and
• said error correction encoding means includes means for inserting said first data of each block into one of said inner codes, with the beginning of said first data coinciding with a predetermined position in said inner code;
• and
• a decoding section including:
• (a) error correction decoding means for correcting errors in compressed picture data received by said decoding means after compression by said digital data compressing means, by utilizing an inner check code and an outer check code, provided by said error correction encoding means and included in said received compressed picture data;
• and
• (b) digital data expanding means for expanding compressed picture data outputted from said error correction decoding means, including variable-length decoding means for decoding said compressed picture data into frequency components, and orthogonal inverse transformer means for generating a picture signal from said frequency components,
• wherein:
• said error correction decoding means including change-over means for selectively outputting either data resulting from error correction by way of said inner check code and outer check code or a signal resulting from error correction by way of only said inner check code, and
• said digital data expanding means further includes combiner means responsive to said first and second data from said error correction decoding means for synthesizing said first data and said second data into one compressed picture data signal composed of full range frequency components.