Method for predicting a block of image data by verifying condition relating temporal variation between image data of reference block and prediction block of previous reference block, decoding and coding devices implementing said method

摘要

A method for predicting a current block belonging to a current image with a view to the coding or the reconstruction of the current block. The method includes determining for the current block a reference block from at least one motion data previously associated with the current block. The fulfillment of a predefined condition is is verified. The predefined condition being representative of a temporal variation between the image data of the reference block and the image data of a prediction block of the reference block previously determined from at least one motion data associated with the reference block. The motion data is modified according to the result of the verification, and a final prediction block for the current block is generated from the motion data of the current block.

主权项

1. The prediction method for a current block belonging to a current image of a sequence of images with a view to the coding or the reconstruction of said current block, each image of said sequence comprising pixels to each of which is associated at least one image data, said method comprising the following steps:
a) determining for the current block a reference block from at least one current motion vector and one current reference index associated with said current block, b) verifying if the following conditions are fulfilled:
a majority of pixels of said reference block are temporally predicted pixels,a prediction error calculated between the image data of said reference block and the image data of a prediction block of said reference block is less than a predefined threshold value, andthe following inequality is verified:
D(mv1/d1;mv2/d2)<α where:
d1 is the distance between the current image and the image of the sequence to which the reference block belongs,d2 is the distance between the current image and the image of the sequence towards which the motion vector associated with said majority of pixels of said reference block,mv1 is the motion vector of said current block,mv2 is the motion vector associated with a majority of pixels of said reference block,D is a distance function; andα is a threshold value; c) when said conditions are fulfilled, adding to said at least one current motion vector a motion vector associated with a majority of pixels of said reference block and modifying said current reference index with the reference index associated with said majority of pixels of said reference block, and e) generating a prediction block for said current block from said at least one current motion vector and from said current reference index.