Image processing device and method

• US 10,027,988 B2
• Filed: 09/09/2013
• Issued: 07/17/2018
• Est. Priority Date: 09/20/2012
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Lu, Shuo, Nakagami, Ohji
• Primary Examiner(s): SENFI, BEHROOZ M
• Application Number:
  US14/420,402
• Publication Number:
  US 20150215652A1
• Time in Patent Office: 1,772 Days
• Field of Search: 37524029
• 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 19/14 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 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/80 Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 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
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

The present invention relates to image processing device and method which can suppress block noise. A filter strength determination unit determines the filter strength for every four lines under the control of a control unit. In other words, if a block boundary determination unit has determined to perform filtering, the filter strength determination unit determines at which strength of the strong filter or the weak filter the filtering process is performed, and outputs the determination result to a filter calculation unit. On this occasion, the filter strength determination unit uses the Bs value in the determination formula of the strong filter. For example, in the case of using the Bs value, the threshold of the determination is set in accordance with a linear function of the Bs value from the control unit. The present disclosure can be applied to, for example, an image processing device.

Claims

1. An image processing device comprising:

circuitry configured to

determine, for a first layer of an image having a plurality of layers, whether to apply a deblocking filter including a first deblocking filter and a second deblocking filter having a stronger filter than the first deblocking filter by using a strength parameter representing strength of a deblocking filter for a block boundary, which is a boundary between a block of the image locally decoded when an image is encoded, and an adjacent block adjacent to the block;

apply the second deblocking filter for the block boundary if the circuitry has determined to apply the second deblocking filter;

apply, to another layer of the image, at least one of the strength parameter and a result of determination of whether to apply the deblocking filter; and

encode the image in coding blocks formed by recursively splitting a coding tree block into smaller coding blocks as block partitioning by using the image to which the second deblocking filter has been applied,

wherein the circuitry is configured to determine whether to apply the second deblocking filter by using the strength parameter representing the strength of the deblocking filter for the block boundary and a determination parameter representing a threshold used in the determination of the deblocking filter, and wherein whether to apply the second deblocking filter is determined by obtaining the determination filter from a table and then comparing a value obtained by multiplying the strength parameter by the determination parameter with a threshold.

2. The image processing device according to claim 1, wherein the circuitry is configured to determine whether to apply the second deblocking filter by using a function in which the strength parameter or the determination parameter is used as a variable.

3. The image processing device according to claim 2, wherein the circuitry is configured to determine whether to apply the second deblocking filter by using a linear function of the strength parameter and the determination parameter.

4. The image processing device according to claim 1, wherein the strength parameter is a parameter that is larger when a prediction mode is intra prediction than when the prediction mode is inter prediction.

5. The image processing device according to claim 4, wherein the strength parameter is Bs (Boundary Filtering Strength) value.

6. The image processing device according to claim 1, wherein the determination parameter is beta used in the determination of whether to apply the deblocking filter and the determination of strength selection of the deblocking filter.

7. An image processing method wherein an image processing device performs the steps of:

determining, using circuitry, for a first layer of an image having a plurality of layers, whether to apply a deblocking filter including a first deblocking filter and a second deblocking filter having a stronger filter than the first deblocking filter by using a strength parameter representing strength of a deblocking filter for a block boundary, which is a boundary between a block of an image locally decoded when an image is encoded, and an adjacent block adjacent to the block;

applying, using the circuitry, the second deblocking filter for the block boundary if it has been determined to apply the second deblocking filter;

applying, using the circuitry, to another layer of the image, at least one of the strength parameter and a result of determination of whether to apply the deblocking filter; and

encoding, using the circuitry, the image in coding blocks formed by recursively splitting a coding tree block into smaller coding blocks as block partitioning by using the image to which the second deblocking filter has been applied,

wherein whether to apply the second deblocking filter is determined by using the strength parameter representing the strength of the deblocking filter for the block boundary and a determination parameter representing a threshold used in the determination of the deblocking filter, and wherein whether to apply the second deblocking filter is determined by obtaining the determination filter from a table and then comparing a value obtained by multiplying the strength parameter by the determination parameter with a threshold.