Complexity reduction of edge-detection based spatial interpolation

摘要

The present invention relates to an efficient implementation of a directional spatial prediction. The directional spatial prediction includes detecting an edge by means of determining a vertical and a horizontal gradient within an adjacent block, determining for each pixel to be predicted an intersection of the detected edge with a boundary row or a column of pixels of the adjacent block, and extrapolating or interpolating each pixel in the block according to the determined intersection. The intersection may be a sub-pel position. In particular, the calculation of the intersection includes dividing by a vertical or a horizontal gradient to obtain an integer slope common for the entire block to be predicted. This reduces the number of divisions to one per block. In order to increase the precision of the division, a scaling by a scaling factor depending on a value of a horizontal or vertical gradient, respectively, may be applied.