IMAGE PROCESSING DEVICE AND METHOD

• US 20140233660A1
• Filed: 10/18/2012
• Published: 08/21/2014
• Est. Priority Date: 10/27/2011
• Status: Abandoned Application

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sato, Kazushi
• Application Number:
  US14/346,888
• Publication Number:
  US 20140233660A1
• Time in Patent Office: Days
• US Class Current: 375/240.29
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/134 characterised by the element, parameter or criterion affecting or controlling the adaptive coding
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/182 the unit being a pixel
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/82 involving filtering within a prediction loop
• CPC Class Codes: H04N 19/86 involving reduction of coding artifacts, e.g. of blockiness

Abstract

The present disclosure relates to image processing devices and methods for more appropriate removal of block distortion and improvement of decoded image quality.

Based on information about a quad-tree structure from an adaptive offset unit, a deblocking filter control unit determines whether the current region in a deblocking filtering process is at a boundary of the current region in an adaptive offset process. If the current region in the deblocking filtering process is at a boundary of the current region in the adaptive offset process, the deblocking filter control unit supplies control information for increasing the filtering strength to a deblocking filter. The present disclosure can be applied to image processing devices, for example.

Claims

1. An image processing device comprising:

a decoding unit configured to decode an encoded stream to generate an image;

an adaptive offset processing unit configured to perform an adaptive offset process on the image generated by the decoding unit;

a deblocking filter adjustment unit configured to adjust strength of a deblocking filtering process when a current region in the deblocking filtering process in the image is determined to be a boundary of the current region in the adaptive offset process based on information about a quad-tree structure used in the adaptive offset process; and

a deblocking filtering unit configured to perform the deblocking filtering process on the image subjected to the adaptive offset process by the adaptive offset processing unit, the deblocking filtering process having the strength adjusted by the deblocking filter adjustment unit.

2. The image processing device according to claim 1, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process, when the current region in the deblocking filtering process and a neighboring region adjacent to the current region in the deblocking filtering process are at a boundary of the current region in the adaptive offset process, and the current region in the deblocking filtering process and the neighboring region are processed with offsets of different types among edge offsets, band offsets, and “

no offset”

.

3. The image processing device according to claim 2, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process, when the current region in the deblocking filtering process and the neighboring region adjacent to the current region in the deblocking filtering process are at a boundary of the current region in the adaptive offset process, and are processed with offsets of the same type and under different categories, the type of the offsets being an edge offset or a band offset.

4. The image processing device according to claim 2, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process with a boundary strength value.

5. The image processing device according to claim 4, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process by incrementing the boundary strength value by +1, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

6. The image processing device according to claim 4, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process by adjusting the boundary strength value to 4, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

7. The image processing device according to claim 2, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process with a value α

or a value β

, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

8. The image processing device according to claim 7, wherein the deblocking filter adjustment unit determines the value α

or the value β

by performing table reduction using a value obtained by adding a quantization parameter QP and a predetermined value Δ

QP, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

9. An image processing method comprising:

generating an image by decoding an encoded stream;

performing an adaptive offset process on the generated image;

adjusting strength of a deblocking filtering process when a current region in the deblocking filtering process in the image is determined to be a boundary of the current region in the adaptive offset process based on information about a quad-tree structure used in the adaptive offset process; and

performing the deblocking filtering process on the image subjected to the adaptive offset process, the deblocking filtering process having the adjusted strength,

an image processing device generating the image, performing the adaptive offset process, adjusting the strength of the deblocking filtering process, and performing the deblocking filtering process.

10. An image processing device comprising:

an adaptive offset processing unit configured to perform an adaptive offset process on an image that is locally decoded at a time of image encoding;

a deblocking filter adjustment unit configured to adjust strength of a deblocking filtering process when a current region in the deblocking filtering process in the image is determined to be a boundary of the current region in the adaptive offset process based on information about a quad-tree structure used in the adaptive offset process;

a deblocking filtering unit configured to perform the deblocking filtering process on the image subjected to the adaptive offset process by the adaptive offset processing unit, the deblocking filtering process having the strength adjusted by the deblocking filter adjustment unit; and

an encoding unit configured to encode the image by using the image subjected to the deblocking filtering process by the deblocking filtering unit.

11. The image processing device according to claim 10, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process, when the current region in the deblocking filtering process and a neighboring region adjacent to the current region in the deblocking filtering process are at a boundary of the current region in the adaptive offset process, and the current region in the deblocking filtering process and the neighboring region are processed with offsets of different types among edge offsets, band offsets, and “

no offset”

.

12. The image processing device according to claim 11, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process, when the current region in the deblocking filtering process and the neighboring region adjacent to the current region in the deblocking filtering process are at a boundary of the current region in the adaptive offset process, and are processed with offsets of the same type and under different categories, the type of the offsets being an edge offset or a band offset.

13. The image processing device according to claim 11, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process with a boundary strength value.

14. The image processing device according to claim 13, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process by incrementing the boundary strength value by +1, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

15. The image processing device according to claim 13, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process by adjusting the boundary strength value to 4, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

16. The image processing device according to claim 11, wherein the deblocking filter adjustment unit adjusts the strength of the deblocking filtering process with a value α

or a value β

, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

17. The image processing device according to claim 16, wherein the deblocking filter adjustment unit determines the value α

or the value β

by performing table reduction using a value obtained by adding a quantization parameter QP and a predetermined value Δ

QP, when the current region in the deblocking filtering process and the neighboring region are at a boundary of the current region in the adaptive offset process and are processed with offsets of different types.

18. An image processing method comprising:

performing an adaptive offset process on an image that is locally decoded at a time of image encoding;

adjusting strength of a deblocking filtering process when a current region in the deblocking filtering process in the image is determined to be a boundary of the current region in the adaptive offset process based on information about a quad-tree structure used in the adaptive offset process;

performing the deblocking filtering process on the image subjected to the adaptive offset process, the deblocking filtering process having the adjusted strength; and

encoding the image by using the image subjected to the deblocking filtering process,

an image processing device performing the adaptive offset process, adjusting the strength of the deblocking filtering process, performing the deblocking filtering process, and encoding the image.