| 摘要 |
The present invention determines different additional a priori information for setting up an image filter depending on the spatial position of an image element within an image. The individual image elements of an image are assigned to one of a plurality of groups and an image filter is set up separately for each group of pixels based on additional a priori information. As the original image data is not available in a decoder, a conventional decoder can only use decoded image data for determining adaptive filter coefficients. However, this decoded image data includes disturbances, such as quantisation noise. The present invention generates additional data for improving the filter efficiency based on undisturbed image data. This additional data for setting up an image filter is determined depending on the spatial position of the pixels within an image. An image is separated into a plurality of groups and separate filter data is determined for each group. The decoder analyses the filter information and determines an adaptive set of filter coefficients for each group of image elements separately. Based on a determined filter coefficient, an adaptive filtering of the decoded image data is performed depending on the spatial positions of the individual image elements. In this way, the decoder applies an improved filtering. |
