IMAGE PROCESSING DEVICE AND METHOD
The present disclosure relates to an image processing device and method that enable suppression of an increase in the amount of coding of a quantization matrix. An image processing device of the present disclosure includes an up-conversion unit configured to up-convert a quantization matrix limited to a size less than or equal to a transmission size that is a maximum size allowed for transmission, from the transmission size to a size that is identical to a block size that is a processing unit of quantization or dequantization. The present disclosure is applicable to, for example, an image processing device for processing image data.
1 . An image processing device, comprising:
a setting unit configured to set a 16×16 quantization matrix corresponding to a 16×16 transform unit by performing a nearest neighbor interpolation process in which each element of the 8×8 quantization matrix is copied as a value for its 3 neighboring elements in a case where the 16×16 transform unit is selected when the image data are to be orthogonal transformed;
a quantization unit configured to quantize transform coefficient data generated by orthogonal transforming the image data in 16×16 transform unit using the 16×16 quantization matrix set by the setting unit to generate quantized data; and
an encoding unit configured to encode the quantized data generated by the quantization unit to generate a bitstream including the 8×8 quantization matrix obtained by thinning out 3 neighboring elements copied with each element of the 8×8 quantization matrix from the 16×16 quantization matrix set by the setting unit.
2 . The image processing device according to claim 1 , wherein the setting unit sets a 32×32 quantization matrix corresponding to a 32×32 transform unit by performing a nearest neighbor interpolation process in which each element of the 8×8 quantization matrix is copied as a value for its 15 neighboring elements in a case where the 32×32 transform unit is selected when the image data are to be orthogonal transformed;
the quantization unit quantizes the transform coefficient data generated by the orthogonal transforming the image data in the 32×32 transform unit using the 32×32 quantization matrix set by the setting unit; and
the encoding unit generates a bitstream including an 8×8 quantization matrix obtained by thinning out 15 elements from every 4 ×4 elements of the 32×32 quantization matrix set by the setting unit.
3 . The image processing device according to claim 2 , wherein the encoding unit sets the 8×8 quantization matrix obtained by thinning out elements from the 32×32 quantization matrix as a picture parameter set of the bitstream.
4 . The image processing device according to claim 1 , wherein the encoding unit sets the 8×8 quantization matrix obtained by thinning out elements from the 16×16 quantization matrix as a picture parameter set of the bitstream.
5 . The image processing device according to claim 1 , further comprising an orthogonal transforming unit configured to orthogonal transform the image data in a 16×16 transform unit to generate the transform coefficient data.
6 . An image processing method, comprising:
setting a 16×16 quantization matrix corresponding to a 16×16 transform unit by performing a nearest neighbor interpolation process in which each element of the 8×8 quantization matrix is copied as a value for its 3 neighboring elements in a case where the 16×16 transform unit is selected when the image data are to be orthogonal transformed;
quantizing transform coefficient data generated by orthogonal transforming the image data in 16×16 transform unit using the set 16×16 quantization matrix to generate quantized data; and
encoding the generated quantized data to generate a bitstream including the 8×8 quantization matrix obtained by thinning out 3 neighboring elements copied with each element of the 8×8 quantization matrix from the set 16×16 quantization matrix.
7 . The image processing method according to claim 6 , wherein setting a 32×32 quantization matrix corresponding to a 32×32 transform unit by performing a nearest neighbor interpolation process in which each element of the 8×8 quantization matrix is copied as a value for its 15 neighboring elements in a case where the 32×32 transform unit is selected when the image data are to be orthogonal transformed;
quantizing the transform coefficient data generated by the orthogonal transforming the image data in the 32×32 transform unit using the set 32×32 quantization matrix; and
generating a bitstream including an 8×8 quantization matrix obtained by thinning out 15 elements from every 4 ×4 elements of the set 32×32 quantization matrix.
8 . The image processing method according to claim 7 , wherein the 8×8 quantization matrix obtained by thinning out elements from the 32×32 quantization matrix is set as a picture parameter set of the bitstream.
9 . The image processing method according to claim 6 , wherein the 8×8 quantization matrix obtained by thinning out elements from the 16×16 quantization matrix is set as a picture parameter set of the bitstream.
10 . The image processing method according to claim 6 , wherein
the image data is orthogonal transformed in a 16×16 transform unit to generate the transform coefficient data.