Image processing apparatus and image processing method

An image processing method comprising:

• generating a decoded image by decoding a coded stream;
• determining deblocking filter application necessity with respect to color difference components of the decoded image based on boundary strength that is calculated by adopting a block boundary of the decoded image as a target, and using information related to transform coefficients of the color difference components obtained by orthogonal transformation;
• and
• applying a deblocking filter to color difference components of pixels located in a vicinity of the block boundary based on a determination result of the deblocking filter application necessity,
• wherein the boundary strength is calculated by independently determining whether a significant coefficient of each of components is present in the blocks that sandwich the block boundary as the target for the calculation of the boundary strength,
• the boundary strength is represented by five bits which correspond to a condition on intra prediction, a condition on a significant coefficient of a Y component, a condition on a significant coefficient of a U component of the color difference components, a condition on a significant coefficient of a V component of the color difference components, and a condition on a motion vector and a reference picture, respectively,
• the deblocking filter application necessity is determined through determination based on the boundary strength and large block determination based on sizes of blocks that sandwich the block boundary, the sizes being sizes in a direction perpendicular to the block boundary of directions perpendicular to and parallel to the block boundary.

An image processing apparatus comprising:

• circuitry configured to
• determine deblocking filter application necessity with respect to color difference components of a decoded image that is decoded based on local decoding process, based on boundary strength that is calculated by adopting a block boundary of the decoded image as a target, and using information related to transform coefficients of the color difference components obtained by orthogonal transformation;
• apply a deblocking filter to color difference components of pixels located in a vicinity of the block boundary based on a determination result of the deblocking filter application necessity;
• and
• encode an image using the decoded image to which the deblocking filter is applied by the filtering unit,
• wherein the boundary strength is calculated by independently determining whether a significant coefficient of each of components is present in the blocks that sandwich the block boundary as the target for the calculation of the boundary strength,
• the boundary strength is represented by five bits which correspond to a condition on intra prediction, a condition on a significant coefficient of a Y component, a condition on a significant coefficient of a U component of the color difference components, a condition on a significant coefficient of a V component of the color difference components, and a condition on a motion vector and a reference picture, respectively,
• determine the deblocking filter application necessity through determination based on the boundary strength and large block determination based on sizes of blocks that sandwich the block boundary, the sizes being sizes in a direction perpendicular to the block boundary of directions perpendicular to and parallel to the block boundary.

An image processing method comprising:

• determining deblocking filter application necessity with respect to color difference components of a decoded image that is decoded based on local decoding process, based on boundary strength that is calculated by adopting a block boundary of the decoded image as a target, and using information related to transform coefficients of the color difference components obtained by orthogonal transformation;
• applying a deblocking filter to color difference components of pixels located in a vicinity of the block boundary based on a determination result of the deblocking filter application necessity;
• and
• coding an image using the decoded image to which the deblocking filter is applied,
• wherein the boundary strength is calculated by independently determining whether a significant coefficient of each of components is present in the blocks that sandwich the block boundary as the target for the calculation of the boundary strength,
• the boundary strength is represented by five bits, which correspond to a condition on intra prediction, a condition on a significant coefficient of a Y component, a condition on a significant coefficient of a U component of the color difference components, a condition on a significant coefficient of a V component of the color difference components, and a condition on a motion vector and a reference picture, respectively,
• the deblocking filter application necessity is determined through determination based on the boundary strength and large block determination based on sizes of blocks that sandwich the block boundary, the sizes being sizes in a direction perpendicular to the block boundary of directions perpendicular to and parallel to the block boundary.