Image data coding apparatus and coding method for dynamic-image data

An image data coding apparatus comprising:

• data generating means for generating at least dynamic images;
• data processing means for arranging image data three-dimensionally for several frames adjoining each other among said dynamic image data generated by said data generating means as three-dimensional image data, and for dividing the three-dimensional image data into a plurality of three-dimensional blocks of a specified size, so as to output each three-dimensional block data;
• first transforming means for applying three-dimensional orthogonal transform to said three-dimensional block data output from said data processing means and for outputting three-dimensional transform coefficient data;
• second transforming means for transforming said three-dimensional coefficient data output from said first transforming means into one-dimensionally-arranged transform coefficient data;
• quantizing means for quantizing said one-dimensionally-arranged transform coefficient data transformed by said second transforming means with a specified quantization width and for generating quantization output;
• coding means for coding said quantization output generated by said quantizing means and for outputting coded output;
• means for controlling a first coding to obtain coding output when said apparatus executes quantization with a temporary quantization width, and for controlling a second coding to obtain coding output when said apparatus executes quantization with an optimum quantization width;
• number-of-code calculating means for calculating the number of codes for each specified two-dimensional block in accordance with said coding output obtained by said first coding, and for calculating the number of codes for one-frame images;
• number-of-code assigning means for assigning the number of codes to each two-dimensional block in accordance with the number of codes for each two-dimensional block calculated by the number-of-code calculating means, the number of codes for one-frame images, and target number of codes;
• estimating means for generating estimation output by estimating an optimum quantization width in accordance with the number of codes for one-frame images calculated by said number-of-code calculating means and the target number of codes;
• and
• means for stopping coding of said coding means when the number of codes assigned to each two-dimensional block by said number-of-code assignment means for said second coding is exceeded.

An image data coding apparatus comprising:

• first storing means for storing image data for several adjoining frames among generated dynamic image data as three-dimensional image data;
• first controlling means for controlling said first storing means in order to divide said three-dimensional image data stored by said first storing means into a plurality of three-dimensional blocks of a specified size and for outputting each three-dimensional block data;
• first transforming means for applying three-dimensional orthogonal transform to said three-dimensional block data output from said first storing means and for outputting three-dimensional transform coefficient data;
• second storing means for storing said three-dimensional transform coefficient data output from said first transforming means;
• second transforming means for controlling said second storing means in order to transform said three-dimensional transform coefficient data sent from said first transforming means into one-dimensionally-arranged transform coefficient data;
• quantizing means for quantizing said one-dimensionally-arranged transform coefficient data output from said second transforming means with a specified quantization width for generating quantization output;
• and
• coding means for coding said quantization output generated by said quantizing means.

An image data coding method comprising the steps of:

• obtaining dynamic image data;
• arranging image data three-dimensionally for several adjoining frames among said dynamic data, and dividing the three-dimensionally arranged image data for each frame into blocks for matrix areas of a specified size;
• applying three-dimensional orthogonal transform to each of the obtained blocks and output three-dimensional transform coefficient data;
• transforming said three-dimensional transform coefficient data into one-dimensionally-arranged transform coefficient data;
• quantizing said one-dimensionally-arranged transform coefficient data with a specified quantization width and outputting quantization output;
• and
• coding said quantization output;
• wherein said step of transforming said three-dimensional transform coefficient data includes a step of scanning, in a specified sequence, the plane approximated to a spherical surface formed centering around the DC component of said three-dimensional transform coefficient data.