Image processing device and method

Patent metadata

Field	Value
Publication number	US-10419756-B2
Application number	US-201715624457-A
Country	US
Kind code	B2
Filing date	Jun 15, 2017
Priority date	Apr 6, 2012
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A β LUT_input calculation unit and a clipping unit calculate β LUT_input that is a value input to an existing β generation unit and an extended β generation unit. When the value of β LUT_input qp from the clipping unit is equal to or less than 51, the existing β generation unit calculates β using the LUT defined in the HEVC method and supplies the calculated β to a filtering determination unit. When the value of β LUT_input qp from the clipping unit is larger than 51, the extended β generation unit calculates extended β and supplies the calculated β to the filtering determination unit. The device can be applied to an image processing device, for example.

First claim

The invention claimed is:

1. An image processing device, comprising:
a decoder configured to generate a decoded image by decoding an encoded stream; and
a filter configured to apply a deblocking filter to pixels neighboring a block boundary within the decoded image using a filter parameter set based on a quantization parameter, the filter parameter being set to be greater than 12 in case that the quantization parameter is equal to 47, wherein
the filter parameter is used during clipping of filtered pixels output by the deblocking filter, and
the filter parameter being set by a look-up table based on a value of the quantization parameter when the value of the quantization parameter is equal to or less than 53.

2. The image processing device according to claim 1 , wherein the quantization parameter is an average of a first quantization parameter and a second quantization parameter between a first block and a second block at the block boundary.

3. The image processing device according to claim 2 , wherein the filter is configured to apply the deblocking filter to the pixels within the decoded image using the filter parameter set according to an extended range, the range being within the extended range.

4. The image processing device according to claim 3 , wherein
the deblocking filter comprises a weak filter with a first strength and a strong filter with a second strength stronger than the first strength, and
the filter parameter is a parameter used during selection of either one of the weak filter and the strong filter or during clipping of the filtered pixels after application of the strong filter.

5. The image processing device according to claim 1 , wherein the block boundary is a boundary of a transformer unit or of a prediction unit.

6. The image processing device according to claim 1 , wherein the decoder comprises:
an arithmetic decoding unit configured to perform an arithmetic decoding process on the encoded stream to generate quantized data;
an inverse quantization unit configured to perform an inverse quantization process on the quantized data to generate transformation coefficient data; and
an inverse orthogonal transformation unit to configured to perform an inverse orthogonal transformation process on the transformation coefficient data.

7. The image processing device according to claim 6 , wherein the decoder is configured to decode the encoded stream according to coding units derived from dividing a largest coding unit recursively.

8. The image processing device according to claim 7 , wherein the coding units are derived from dividing the largest coding unit in accordance with a quad-tree structure.

9. The image processing device according to claim 8 , wherein the largest coding unit is a coding unit in the top level of the quad-tree structure.

10. The image processing device according to claim 9 , wherein
the largest coding unit is a block of fixed size under sequence level, and
the coding unit is a block of variable size.

11. An image processing method, comprising:
generating a decoded image by decoding an encoded stream; and
applying a deblocking filter to pixels neighboring a block boundary within the decoded image using a filter parameter set based on a quantization parameter, the filter parameter being set to be greater than 12 in case that the quantization parameter is equal to 47, wherein
the filter parameter is used during clipping of filtered pixels output by the deblocking filter, and
the filter parameter being set by a look-up table based on a value of the quantization parameter when the value of the quantization parameter is equal to or less than 53.

12. The image processing method according to claim 11 , wherein the quantization parameter is an average of a first quantization parameter and a second quantization parameter between a first block and a second block at the block boundary.

13. The image processing method according to claim 12 , wherein the deblocking filter is applied to the pixels within the decoded image using the filter parameter set according to an extended range, the range being within the extended range.

14. The image processing method according to claim 13 , wherein
the deblocking filter comprises a weak filter with a first strength and a strong filter with a second strength stronger than the first strength, and
the filter parameter is a parameter used during selection of either one of the weak filter and the strong filter or during clipping of the filtered pixels after application of the strong filter.

15. The image processing method according to claim 11 , wherein the block boundary is a boundary of a transformer unit or of a prediction unit.

16. The image processing method according to claim 11 , wherein generating the decoded image comprises:
performing an arithmetic decoding process on the encoded stream to generate quantized data;
performing an inverse quantization process on the quantized data to generate transformation coefficient data; and
performing an inverse orthogonal transformation process on the transformation coefficient data.

17. The image processing method according to claim 16 , wherein generating the decoded image further includes decoding the encoded stream according to coding units derived from dividing a largest coding unit recursively.

18. An image processing device, comprising:
circuitry configured to:
decode an encoded stream to generate a decoded image; and
apply a deblocking filter to pixels neighboring a block boundary within the decoded image using a filter parameter set based on a quantization parameter, the filter parameter being set to be greater than 12 in case that the quantization parameter is equal to 47, wherein

the filter parameter is used during clipping of filtered pixels output by the deblocking filter, and
the filter parameter being set by a look-up table based on a value of the quantization parameter when the value of the quantization parameter is equal to or less than 53.

19. The image processing device according to claim 1 , wherein the filter parameter is set by evaluating the function of the quantization parameter as follows:
tc (qp)=max(round(0.5*qp−13.5), i ),

wherein tc is the filter parameter and qp is the quantization parameter.

20. The image processing method according to claim 11 , wherein the filter parameter is set by evaluating the function of the quantization parameter as follows:
tc (qp)=max(round(0.5*qp−13.5),1),

wherein tc is the filter parameter and qp is the quantization parameter.

21. The image processing device according to claim 18 , wherein the filter parameter is set by evaluating the function of the quantization parameter as follows:
tc (qp)=max(round(0.5*qp−13.5),1),

wherein tc is the filter parameter and qp is the quantization parameter.

Assignees

• Sony Corp

Inventors

• Lu Shuo
• Ikeda Masaru

Classifications

• H04N19/86 Primary

  involving reduction of coding artifacts, e.g. of blockiness · CPC title

• H04N19/44

  Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder · CPC title

• H04N19/117 Primary

  Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) · CPC title