Method and device for coding image and method and device for decoding image

A method for image decoding, comprising:

• parsing a bitstream to acquire at least one decoding parameter of a decoding block, wherein the at least one decoding parameter comprises at least one of the following parameters:
• at least one parameter for constructing a representative pixel set of the decoding block, and at least one parameter for constructing predicted values of pixel samples in the decoding block;
• and
• constructing the representative pixel set, and determining predicted values, wherein a generation manner for the predicted values comprises:
• constructing the predicted values according to reconstructed pixel samples and pixel values of the representative pixel set,
• wherein, for the pixel samples in the decoding block, the generation manner for the predicted values comprises:
• for the reconstructed pixel samples outside the decoding block, calculating distances between the reconstructed pixel samples and part or all of representative pixel samples of the representative pixel set, and setting the representative pixel samples of which the distances meet a first predefined condition as optimal representative pixel samples;
• and
• under the condition that distances between the optimal representative pixel samples and the reconstructed pixel samples meet a second predefined condition, setting numerical values of the optimal representative pixel samples as the predicted values, and when the distances between the optimal representative pixel samples and the reconstructed pixel samples do not meet the second predefined condition, setting the numerical values of the reconstructed pixel samples as the predicted values.

A device for image coding, comprising:

• a first determination component, arranged to construct a representative pixel set of a coding block within the coding block and determine information for constructing the representative pixel set;
• a second determination component, arranged to construct predicted values of pixel samples of the coding block, a generation manner for the predicted values comprising:
• constructing the predicted values of the pixel samples according to reconstructed pixel samples in an image region outside the coding block and pixel values of the representative pixel set in the block;
• and
• a coding component, arranged to code and write the information for constructing the representative pixel set and information for constructing the predicted values into a bitstream;
• wherein, for the pixel samples in the coding block, the generation manner for the predicted values comprises:
• for the reconstructed pixel samples outside the coding block, calculating distances between the reconstructed pixel samples and part or all of representative pixel samples of the representative pixel set, and setting the representative pixel samples of which the distances meet a first predefined condition as optimal representative pixel samples;
• and
• under the condition that distances between the optimal representative pixel samples and the reconstructed pixel samples meet a second predefined condition, setting numerical values of the optimal representative pixel samples as the predicted values, and when the distances between the optimal representative pixel samples and the reconstructed pixel samples do not meet the second predefined condition, setting the numerical values of the reconstructed pixel samples as the predicted values.

A device for image decoding, comprising:

• a parsing component, arranged to parse a bitstream to acquire at least one decoding parameter of a decoding block, wherein the at least one decoding parameter comprises at least one of the following parameters:
• at least one parameter for constructing a representative pixel set of the decoding block, and at least one parameter for constructing predicted values of pixel samples in the decoding block;
• and
• a third determination component, arranged to construct the representative pixel set, and determine predicted values, wherein a generation manner for the predicted values comprises:
• constructing the predicted values according to reconstructed pixel samples and pixel values of the representative pixel set;
• wherein, for the pixel samples in the decoding block, the generation manner for the predicted values comprises:
• for the reconstructed pixel samples outside the decoding block, calculating distances between the reconstructed pixel samples and part or all of representative pixel samples of the representative pixel set, and setting the representative pixel samples of which the distances meet a first predefined condition as optimal representative pixel samples;
• and
• under the condition that distances between the optimal representative pixel samples and the reconstructed pixel samples meet a second predefined condition, setting numerical values of the optimal representative pixel samples as the predicted values, and when the distances between the optimal representative pixel samples and the reconstructed pixel samples do not meet the second predefined condition, setting the numerical values of the reconstructed pixel samples as the predicted values.