Image processing device and method
The present disclosure relates to an image processing device and method that allow reduction in coding efficiency to be suppressed. A pixel value of a chroma component is predicted by linear prediction from a pixel value of a reference image of a luma component whose pixel location is changed by using a filter, and a prediction image of the chroma component is generated. A chroma component of encoded data in which an image is encoded is decoded by using the generated prediction image. The filter is selected on a basis of information regarding a pixel location of the chroma component and information regarding a color format. The present disclosure is applicable, for example, to an image processing device, an image encoding device, an image decoding device, or the like.
1. An image processing device comprising:
circuitry configured to
predict a pixel value of a chroma component of encoded data by linear prediction from a pixel value of a luma component of the encoded data at a pixel location of the luma component that is determined using a filter selected on a basis of information regarding a pixel location of the chroma component and information regarding a color format of the encoded data;
generate a prediction image of the chroma component based on the predicted pixel value of the chroma component; and
decode the chroma component of the encoded data using the prediction image.
2. The image processing device according to claim 1 , wherein the circuitry is configured to:
select a filter on the basis of the information regarding the pixel location of the chroma component and the information regarding color format, the filter changing the pixel location of the luma component,
predict the pixel value of the chroma component by linear prediction from the pixel value of the luma component whose pixel location is changed by the filter, and
generate the prediction image of the chroma component based on the predicted pixel value of the chroma component.
3. The image processing device according to claim 2 , wherein the circuitry is configured to select a candidate in a candidate group as the filter, the candidate group supporting a plurality of color formats, the candidate corresponding to a color format and the information regarding the pixel location of the chroma component, the color format including a format designated by the information regarding the color format.
4. The image processing device according to claim 2 , wherein the circuitry is configured to select the filter on a basis of linear prediction mode information, the information regarding the pixel location of the chroma component, and the information regarding the color format, the linear prediction mode information including information regarding a mode of the linear prediction.
5. The image processing device according to claim 2 , wherein the circuitry is configured to
change the pixel location of the luma component by using the filter,
predict the pixel value of the chroma component by linear prediction from the pixel value of the luma component whose location is changed, and
generate the prediction image of the chroma component based on the predicted pixel value of the chroma component.
6. The image processing device according to claim 1 , wherein
the chroma component includes a Cb component and a Cr component, and
the circuitry is configured to correct the prediction image of the Cr component by using a collocate block of the Cb component, the collocate block corresponding to the prediction image of the Cr component.
7. The image processing device according to claim 1 , wherein the circuitry is configured to
acquire the information regarding the pixel location of the chroma component included in the encoded data, and
generate the prediction image of the chroma component by the linear prediction by using the pixel value of the luma component whose pixel location is changed on a basis of the information regarding the pixel location of the chroma component.
8. The image processing device according to claim 1 , wherein the circuitry is configured to acquire cross-chroma residual prediction information indicating whether to correct a prediction image of a Cr component by using a collocate block of a Cb component corresponding to the prediction image of the Cr component, the cross-chroma residual prediction information being included in the encoded data.
9. The image processing device according to claim 8 , wherein the circuitry is configured to
acquire cross-chroma residual prediction enabled information indicating whether or not the cross-chroma residual prediction information is enabled, and
acquire the cross-chroma residual prediction information included in the encoded data on condition that the cross-chroma residual prediction enabled information indicates that the cross-chroma residual prediction information is enabled, the cross-chroma residual prediction enabled information being included in the encoded data.
10. An image processing method comprising:
predicting a pixel value of a chroma component of encoded data by linear prediction from a pixel value of a luma component of the encoded data at a pixel location of the luma component that is determined using a filter selected on a basis of information regarding a pixel location of the chroma component and information regarding a color format of the encoded data;
generating a prediction image of the chroma component based on the predicted pixel value of the chroma component; and
decoding the chroma component of the encoded data using the prediction image.
11. An image processing device comprising:
circuitry configured to
predict a pixel value of a chroma component of an image by linear prediction from a pixel value of a luma component of the image at a pixel location of the luma component that is determined using a filter selected on a basis of information regarding a pixel location of the chroma component and information regarding a color format of the image;
generate a prediction image of the chroma component based on the predicted pixel value of the chroma component; and
encode the chroma component of the image using the prediction image.
12. The image processing device according to claim 11 , wherein the circuitry is configured to:
select a filter on the basis of the information regarding the pixel location of the chroma component and the information regarding color format, the filter changing the pixel location of the luma component,
predict the pixel value of the chroma component by linear prediction from the pixel value of the luma component whose pixel location is changed by the filter, and
generate the prediction image of the chroma component based on the predicted pixel value of the chroma component.
13. The image processing device according to claim 12 , wherein the circuitry is configured to select a candidate in a candidate group as the filter, the candidate group supporting a plurality of color formats, the candidate corresponding to a color format and the information regarding the pixel location of the chroma component, the color format including a format designated by the information regarding the color format.
14. The image processing device according to claim 12 , wherein the circuitry is configured to select the filter on a basis of linear prediction mode information, the information regarding the pixel location of the chroma component, and the information regarding the color format, the linear prediction mode information including information regarding a mode of the linear prediction.
15. The image processing device according to claim 12 , wherein the circuitry is configured to
change the pixel location of the luma component by using the filter,
predict the pixel value of the chroma component by linear prediction from the pixel value of the luma component whose location is changed, and
generate the prediction image of the chroma component based on the predicted pixel value of the chroma component.
16. The image processing device according to claim 11 , wherein
the chroma component includes a Cb component and a Cr component, and
the circuitry is configured to correct the prediction image of the Cr component by using a collocate block of the Cb component, the collocate block corresponding to the prediction image of the Cr component.
17. The image processing device according to claim 11 , wherein the circuitry is configured to add the information regarding the pixel location of the chroma component to the encoded chroma component.
18. The image processing device according to claim 11 , wherein the circuitry is configured to add cross-chroma residual prediction information to encoded data, the cross-chroma residual prediction information indicating whether to correct a prediction image of a Cr component by using a collocate block of a Cb component corresponding the prediction image of the Cr component.
19. The image processing device according to claim 18 , wherein the circuitry is configured to add cross-chroma residual prediction enabled information to the encoded data, and adds the cross-chroma residual prediction information to the encoded data in a case where the cross-chroma residual prediction enabled information indicates that the cross-chroma residual prediction information is enabled, the cross-chroma residual prediction enabled information indicating whether or not the cross-chroma residual prediction information is enabled.
20. An image processing method comprising:
predicting a pixel value of a chroma component of an image by linear prediction from a pixel value of a luma component of the image at a pixel location of the luma component determined using a filter selected on a basis of information regarding a pixel location of the chroma component and information regarding a color format of the image;
generating a prediction image of the chroma component based on the predicted pixel value of the chroma component; and
encoding the chroma component of the image using the generated prediction image.