Image encoding method, image decoding method, image encoding apparatus, image decoding apparatus, image encoding program, and image decoding program

Abstract

An image encoding/decoding apparatus for performing encoding/decoding while predicting an image between different views using a reference image for a view different from a processing target image and a reference depth map which is a depth map for an object of the reference image when a multi-view image including images of a plurality of different views is encoded/decoded includes a reference depth region setting unit configured to set a reference depth region which is a corresponding region on the reference depth map for decoding target regions into which the processing target image is divided, and an inter-view prediction unit configured to generate an inter-view predicted image for the processing target region from the reference image using depth information in the reference depth region as depth information for the processing target region.

1 . An image decoding apparatus which performs decoding while predicting an image between different views using a reference image decoded for a view different from a decoding target image and a reference depth map which is a depth map for an object of the reference image when the decoding target image is decoded from encoded data of a multi-view image including images of a plurality of different views, the image decoding apparatus comprising:
 a reference depth region setting unit configured to set a reference depth region which is a corresponding region on the reference depth map for decoding target regions into which the decoding target image is divided;   an inter-view prediction unit configured to set an image reference disparity vector which is a disparity vector for the reference image using depth information in the reference depth region and generate an inter-view predicted image for the decoding target region from the reference image and the image reference disparity vector; and   an image decoding unit configured to decode the decoding target image from the inter-view predicted image and the encoded data,   wherein a view of the reference depth map is different from a view of the decoding target image.   
     
     
         2 . The image decoding apparatus according to  claim 1 , further comprising:
 a depth reference disparity vector setting unit configured to set a depth reference disparity vector which is a disparity vector for a reference depth map with respect to the decoding target region,   wherein the reference depth region setting unit sets a region indicated by the depth reference disparity vector as the reference depth region.   
     
     
         3 . The image decoding apparatus according to  claim 2 , wherein the depth reference disparity vector setting unit sets the depth reference disparity vector using a disparity vector used when a region adjacent to the decoding target region is decoded. 
     
     
         4 . The image decoding apparatus according to  claim 2 , wherein the depth reference disparity vector setting unit sets the depth reference disparity vector using depth information for a region on the reference depth map having the same position as the decoding target region. 
     
     
         5 . The image decoding apparatus according to  claim 1 , wherein the inter-view prediction unit sets a representative depth using depth information within the corresponding reference depth region for every predicted region obtained by dividing the decoding target region and generates the inter-view predicted image for the decoding target region by generating a view-synthesized image from the representative depth and the reference image. 
     
     
         6 . The image decoding apparatus according to  claim 1 , wherein the inter-view prediction unit sets the image reference disparity vector which is a disparity vector for the reference image using depth information within the corresponding reference depth region for every predicted region obtained by dividing the decoding target region and generates the inter-view predicted image for the decoding target region by generating a disparity-compensated image using the image reference disparity vector and the reference image. 
     
     
         7 . The image decoding apparatus according to  claim 6 , further comprising:
 an image reference disparity vector accumulation unit configured to accumulate the image reference disparity vector; and   a disparity prediction unit configured to generate predicted disparity information for a region adjacent to the decoding target region using the accumulated image reference disparity vector.   
     
     
         8 . The image decoding apparatus according to  claim 7 , wherein the disparity prediction unit generates a depth reference disparity vector for a region adjacent to the decoding target region. 
     
     
         9 . The image decoding apparatus according to  claim 6 , further comprising:
 a correction disparity vector setting unit configured to set a correction disparity vector which is a vector for correcting the image reference disparity vector,   wherein the inter-view prediction unit generates the inter-view predicted image by generating a disparity-compensated image using a vector obtained by correcting the image reference disparity vector through the correction disparity vector and the reference image.   
     
     
         10 . The image decoding apparatus according to  claim 9 , wherein the correction disparity vector setting unit sets one vector as the correction disparity vector for the decoding target region. 
     
     
         11 . The image decoding apparatus according to  claim 5 , further comprising:
 a predicted region division setting unit configured to set region divisions within the decoding target region based on depth information within the reference depth region,   wherein the inter-view prediction unit designates a region obtained according to the region division as the predicted region.   
     
     
         12 . The image decoding apparatus according to  claim 6 , further comprising:
 a predicted region division setting unit configured to set region divisions within the decoding target region based on depth information within the reference depth region,   wherein the inter-view prediction unit designates a region obtained according to the region division as the predicted region.   
     
     
         13 . An image decoding method which performs decoding while predicting an image between different views using a reference image decoded for a view different from a decoding target image and a reference depth map which is a depth map for an object of the reference image when the decoding target image is decoded from encoded data of a multi-view image including images of a plurality of different views, the image decoding method comprising:
 a reference depth region setting step of setting a reference depth region which is a corresponding region on the reference depth map for decoding target regions into which the decoding target image is divided;   an image reference disparity vector setting step of setting an image reference disparity vector which is a disparity vector for the reference image using depth information in the reference depth region;   an inter-view prediction step of generating an inter-view predicted image for the decoding target region from the reference image and the image reference disparity vector; and   an image decoding step of decoding the decoding target image from the inter-view predicted image and the encoded data,   wherein a view of the reference depth map is different from a view of the decoding target image.   
     
     
         14 . An image encoding apparatus which performs encoding while predicting an image between different views using a reference image encoded for a different view from an encoding target image and a reference depth map which is a depth map for an object of the reference image when a multi-view image including images of a plurality of different views is encoded, the image encoding apparatus comprising:
 a reference depth region setting unit configured to set a reference depth region which is a corresponding region on the reference depth map for encoding target regions into which the encoding target image is divided;   an inter-view prediction unit configured to set an image reference disparity vector which is a disparity vector for the reference image using depth information in the reference depth region and generate an inter-view predicted image for the encoding target region from the reference image and the image reference disparity vector; and   an image encoding unit configured to encode the encoding target image using the inter-view predicted image,   wherein a view of the reference depth map is different from a view of the encoding target image.   
     
     
         15 . An image encoding method which performs encoding while predicting an image between different views using a reference image encoded for a different view from an encoding target image and a reference depth map which is a depth map for an object of the reference image when a multi-view image including images of a plurality of different views is encoded, the image encoding method comprising:
 a reference depth region setting step of setting a reference depth region which is a corresponding region on the reference depth map for encoding target regions into which the encoding target image is divided;   an disparity vector setting step of setting an image reference disparity vector which is a disparity vector for the reference image using depth information in the reference depth region;   an inter-view prediction step of generating an inter-view predicted image for the encoding target region from the reference image and the image reference; and   an image encoding step of encoding the encoding target image using the inter-view predicted image,   wherein a view of the reference depth map is different from a view of the encoding target image.   
     
     
         16 . A non-transitory computer-readable recoding medium having an image decoding program for causing a computer to execute the image decoding method according to  claim 13 . 
     
     
         17 . A non-transitory computer-readable recoding medium having an image encoding program for causing a computer to execute the image encoding method according to  claim 15 .