AUTOGRESSIVE PIXEL PREDICTION IN THE NEIGHBORHOOD OF IMAGE BORDERS

摘要

The Invention refers to a method for coding digital image data (I), the data comprising one or more arrays of pixels (p0, ..., p112) with corresponding pixel values (i0, ..., i112). For each array of pixels, an autoregressive pixel-prediction method is performed based on a weighted sum of reconstructed pixel values (i1, ..., i12) of reconstructed pixels (p1, ..., p12) in a specific neighborhood region (SN) adjacent to the current pixel (p0) to be coded. For determining the weights, the pixel values (p1, ..., p12) in a specific training region (ST) adjacent to the current pixel (p0) are taken into account. The coding method is characterized by an appropriate determination of the specific neighborhood region (SN) and the specific training region (ST) in case that reconstructed pixel values do not exist for all pixels in the neighborhood region and the training region, e.g. at borders of the array of pixels. In such a case, the number of pixels in the neighborhood region is reduced to a number of reconstructed pixels until the ratio between the number of pixels in the training region and the number of pixels in the neighborhood region exceeds a predetermined threshold. The coding method of the invention provides a prediction with high accuracy and, thus, leads to an efficient coding of the image data.