Method and device for coding and decoding an image by block cutting into zones

A device for encoding or decoding at least one image, each image being split into blocks of elements, said device comprising at least one computing machine dedicated or configured, for at least one block, to:

• split the block into at least two areas;
• and
• process at least one said area, comprising scanning the elements of the area according to a predetermined scanning order, and for at least one scanned element, called current element:
• selecting at least one predictor element previously encoded or decoded according to a prediction function;
• predicting the current element into a predicted current element:
• from the at least one predictor element, if the at least one predictor element belongs to said area;
• from at least one replacement value obtained independently of the at least one other area from at least one other predictor element, selected in a previously encoded or decoded block in a vicinity of the current block, otherwise;
• obtaining a residue element by subtraction of the predicted current element from the current element;
• and
• encoding the residue element and inserting the encoded residue element in encoded data representative of said image.

A non-transitory computer-readable medium comprising a computer program product stored thereon and having instructions for implementing a method of encoding or decoding at least one image when the instructions are executed by a processor of an encoding or decoding device, wherein each image is split into blocks and the instructions configure the encoding or decoding device to, for at least one block:

• split the block into at least two areas;
• and
• process at least one said area, comprising scanning the elements of the area according to a predetermined scanning order, and for at least one scanned element, called current element:
• selecting at least one predictor element previously encoded or decoded according to a prediction function;
• predicting the current element into a predicted current element:
• from the at least one predictor element, if the at least one predictor element belongs to said area;
• from at least one replacement value obtained independently of the at least one other area from at least one other predictor element, selected in a previously encoded or decoded block in a vicinity of the current block, otherwise;
• obtaining a residue element by subtraction of the predicted current element from the current element;
• and
• encoding the residue element and inserting the encoded residue element in encoded data representative of said image.

A method for encoding or decoding at least one image, each image being split into blocks of elements, said method being performed by an encoding or decoding device and comprising, for at least one block:

• splitting the block into at least two areas;
• and
• processing at least one said area, comprising scanning the elements of the area according to a predetermined scanning order, and for at least one scanned element, called current element:
• selecting at least one predictor element previously encoded or decoded according to a prediction function;
• and
• predicting the current element:
• from the at least one predictor element, if the at least one predictor element belongs to said area;
• from at least one replacement value obtained independently of the at least one other area, otherwise,
• wherein the current element being located on a row (lin) and a column (col), the prediction function selects a previously processed first element on the same row (lin) and on the previous column (col−1), a previously processed second element on the previous row (lin−1) and on the same previous column (col) and a previously processed third element on the previous row and column (lin−1, col−1) and a boundary between said at least two areas is diagonal, and
• wherein or a block comprising H rows and W columns, the current block is split into two areas, such that the elements of the first area meet the condition lin+col<(H+W)/2+1.