Image compression method and apparatus for suppressing quantization rate in particular region, image expansion method and apparatus therefor, and computer-readable storage medium storing program for the compression or expansion

An image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein code blocks constitute a minimum unit of a collection of bit-planes restructured in a layer different from that of bit-planes in a region which is separated from a tile boundary and has a quantization rate high relative to others, and at least one code block is non-adjacent to an outer edge of a tile.

An image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein precincts constitute a minimum unit of a collection of bit-planes restructured in a layer different from that of bit-planes in a region which is separated from a tile boundary and has a quantization rate high relative to others, and at least one precinct is non-adjacent to an outer edge of a tile.

An image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein bit-planes restructured in a layer different from that of bit-planes in a region which is separated from a tile boundary and has a quantization rate high relative to others have a 15 decomposition level 1 or 2.

The image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said regions of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein bit-planes restructured in a layer different from that of bit-planes in a region which is separated from a tile boundary and has a quantization rate high relative to others have one or a plurality of subbands.

An image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein bit-planes restructured in a layer different from that of bit-planes in a region which is separated from a tile boundary and has a quantization rate high relative to others have wavelet coefficient values greater than a predetermined value.

The image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves;
• and
• a layer restructuring section restructuring a layer by shifting all bit-planes included in a precinct so as to be included in a higher layer when more than a predetermined number of code blocks forming the precinct are adjacent to a tile boundary.

An image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein said suppressing section suppresses the quantization rate of the region of interest in a vicinity of a tile boundary.

An image compression apparatus comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region low relative to other regions of the image,
• wherein said suppressing section selects the region in which the quantization rate is suppressed by a region in a vicinity of a tile boundary.

An image compression method comprising:

• a tile specifying step specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing step dividing the image using the specified rectangular tiles;
• a bit-plane decomposing step decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering step ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming step forming layers by the ordered bit-planes;
• and
• a suppressing step suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein said suppressing step suppresses the quantization rate of a region in a vicinity of a tile boundary, with respect to a bit-plane of a region separated from the tile boundary and having a relatively higher Quantization rate, so as to be included in a higher layer of the layers formed by the ordered bit-planes without shifting the bit-planes themselves.

An image compression method comprising:

• a tile specifying section specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing section dividing the image using the specified rectangular tiles;
• a bit-plane decomposing section decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming section forming layers by the ordered bit-planes;
• and
• a suppressing section suppressing a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein said suppressing step suppresses the quantization rate of the region of interest in a vicinity of a tile boundary.

An image compression method comprising:

• a tile specifying step specifying rectangular tiles having an arbitrary size with respect to an image;
• an image dividing step dividing the image using the specified rectangular tiles;
• a bit-plane decomposing step decomposing each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering step ordering the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming step forming layers by the ordered bit-planes;
• and
• a suppressing step suppressing a quantization rate of a region low relative to other regions of the image,
• wherein said suppressing step selects the region in which the quantization rate is suppressed by a region in a vicinity of a tile boundary.

A computer-readable storage medium which stores a computer program for causing a computer to carry out an image compression, said computer program comprising:

• a tile specifying procedure causing the computer to specify rectangular tiles having an arbitrary size with respect to an image;
• an image dividing procedure causing the computer to divide the image using the specified rectangular tiles;
• a bit-plane decomposing procedure causing the computer to decompose each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering procedure causing the computer to order the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming procedure causing the computer to form layers by the ordered bit-planes;
• and
• a suppressing procedure causing the computer to suppress a quantization rate of a region of interest low relative to other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein said suppressing procedure causes the computer to suppresses the quantization rate of a region in a vicinity of a tile boundary, with respect to a bit-plane of a region separated from the tile boundary and having a relatively higher canalization rate, so as to be included in a higher layer of the layers formed by the ordered bit-planes without shifting the bit-planes themselves.

A computer-readable storage medium which stores a program for causing a computer to carry out an image compression, said program comprising:

• a tile specifying procedure causing the computer to specify rectangular tiles having an arbitrary size with respect to an image;
• an image dividing procedure causing the computer to divide the image using the specified rectangular tiles;
• a bit-plane decomposing procedure causing the computer to decompose each of the specified tiles dividing the image into bit-planes;
• a bit-plane ordering section ordering procedure causing the computer to order the bit-planes decomposing each of the specified tiles depending on a coding sequence;
• a layer forming procedure causing the computer to form layers by the ordered bit-planes;
• and
• a suppressing procedure causing the computer to suppress a canalization rate of a region of interest low relative to each other regions of the image by including a bit-plane of said region of interest in a higher layer of the layers formed by the ordered bit-planes than the other regions without shifting the bit-planes themselves,
• wherein said suppressing procedure causes the computer to suppress the quantization rate of the region of interest in a vicinity of a tile boundary.

An image compression apparatus comprising:

• a dividing part configured to divide an original image into a plurality of tiles;
• an interpolating part configured to interpolate first data in a periphery of each of the tiles and carrying out a wavelet transform;
• a quantizing part configured to quantize transformed wavelet coefficient values to compress image data of the original image;
• and
• a reducing part configured to reduce a quantization rate of the wavelet coefficient values in a region in a vicinity of a tile boundary to a value lower than that of other regions.

An image compression method comprising the steps of:

• dividing an original image into a plurality of tiles;
• interpolating data in a periphery of each of the tiles and carrying out a wavelet transform;
• quantizing transformed wavelet coefficient values to compress image data of the original image;
• and
• reducing a quantization rate of the wavelet coefficient values in a region in a vicinity of a tile boundary to a value lower than that of other regions.

A computer-readable storage medium which stores a program for causing a computer to carry out an image compression, said program comprising:

• a procedure causing the computer to divide an original image into a plurality of tiles;
• a procedure causing the computer to interpolate data in a periphery of each of the tiles and carrying out a wavelet transform;
• a procedure causing the computer to quantize transformed wavelet coefficient values to compress image data of the original image;
• and
• a procedure causing the computer to reduce a quantization rate of the wavelet coefficient values in a region in a vicinity of a tile boundary to a value lower than that of other regions.