Image encoding method and apparatus, image decoding method and apparatus, and programs therefor

An image decoding method in which when decoding encoded data of an image, a frame of the image is divided into predetermined-sized processing regions, and for each processing region, a pixel value of each pixel is predicted for the decoding, wherein the method comprising:

• an object number determination step that determines an object number that indicates the number of objects present in the processing region;
• an object map decoding step that decodes an object map from the encoded data, where the object map indicates the object obtained at each pixel in the processing region, by using an object identifier;
• an object pixel value decoding step that decodes, from the encoded data, an object pixel value assigned to each individual object identifier;
• a predicted image generation step that generates a predicted image for the processing region by assigning the object pixel value to each pixel in accordance with the object map;
• and
• an image signal decoding step that decodes, from the encoded data, an image signal for the processing region by using the predicted image.

An image decoding method in which when decoding encoded data of an image, a frame of the image is divided into predetermined-sized processing regions, and for each processing region, a pixel value of each pixel is predicted for the decoding, wherein the method comprising:

• an object map decoding step that decodes an object map from the encoded data, where the object map indicates an object obtained at each pixel in the processing region, by using an object identifier;
• an object pixel value decoding step that decodes, from the encoded data, an object pixel value assigned to each individual object identifier;
• a predicted image generation step that generates a predicted image for the processing region by assigning the object pixel value to each pixel in accordance with the object map;
• and
• an image signal decoding step that decodes, from the encoded data, an image signal for the processing region by using the predicted image.

An image encoding apparatus in which when transmitting or storing an image, a frame of the image is divided into predetermined-sized processing regions, and for each processing region, a pixel value of each pixel is predicted for the encoding, wherein the apparatus comprising:

• an object number determination device that determines an object number that indicates the number of objects present in the processing region;
• an object pixel value determination device that determines one pixel value, which is assigned to and represents each individual object in the processing region, to be an object pixel value that is associated with an object identifier for identifying the relevant object;
• an object map generation device that generates, based on each object pixel value and the pixel value of each pixel in the processing region, an object map that indicates which object has been obtained at each pixel in the processing region, by using the object identifier;
• a predicted image generation device that generates a predicted image for the processing region by assigning the object pixel value to each pixel in accordance with the object map;
• an object map encoding device that encodes the object map;
• an object pixel value encoding device that encodes each object pixel value;
• and
• an image signal encoding device that performs predictive encoding of an image signal for the processing region by using the predicted image.

An image decoding apparatus in which when decoding encoded data of an image, a frame of the image is divided into predetermined-sized processing regions, and for each processing region, a pixel value of each pixel is predicted for the decoding, wherein the apparatus comprising:

• an object number determination device that determines an object number that indicates the number of objects present in the processing region;
• an object map decoding device that decodes an object map from the encoded data, where the object map indicates the object obtained at each pixel in the processing region, by using an object identifier;
• an object pixel value decoding device that decodes, from the encoded data, an object pixel value assigned to each individual object identifier;
• a predicted image generation device that generates a predicted image for the processing region by assigning the object pixel value to each pixel in accordance with the object map;
• and
• an image signal decoding device that decodes, from the encoded data, an image signal for the processing region by using the predicted image.

An image decoding apparatus in which when decoding encoded data of an image, a frame of the image is divided into predetermined-sized processing regions, and for each processing region, a pixel value of each pixel is predicted for the decoding, wherein the apparatus comprising:

• an object map decoding device that decodes an object map from the encoded data, where the object map indicates an object obtained at each pixel in the processing region, by using an object identifier;
• an object pixel value decoding device that decodes, from the encoded data, an object pixel value assigned to each individual object identifier;
• a predicted image generation device that generates a predicted image for the processing region by assigning the object pixel value to each pixel in accordance with the object map;
• and
• an image signal decoding device that decodes, from the encoded data, an image signal for the processing region by using the predicted image.