Abstract: A method of filtering a signal includes determining a class of a section (23;39) of the signal obtained as input, wherein the determination of the class includes calculating a signal section (28;41) comprising at least a component representative of a derivative of at least a first order of the input signal section (23;39) and applying a quantisation operation to the calculated signal section (28;41). A digital filter associated with the class is selected from a plurality of available filters. In the quantisation operation, a quantisation step is adapted to a dynamic range of the calculated signal section (28;41).

Abstract: In a method for color enhancement the color distance between spatially close colored pixel or pixel areas does not change more than a threshold, the threshold being a function of the initial color distance. The color difference between pixels that are close together and did not differ much in color will be restricted. This reduces the change on unnatural looking parts of an image and allows more pronounced color enhancement to be 5 used.

Abstract: The invention relates to an apparatus and a method for computing an output image (145) on the basis of an input image (100). The method comprises the steps of splitting (105) the input image (100) into multiple sub-images, each sub-image comprising information from a respective frequency band of the input image (100), calculating (110) a pixel headroom signal quantifying the margin available for enhancement of pixel values of pixels in the input image (100), calculating (115) pixel enhancement factors for pixels within sub-images to be modified in dependence upon the pixel headroom signal, such that the margin as quantified by the pixel headroom signal is spread across the respective sub-images to be modified, modifying (120) the respective sub-images by using the pixel enhancement factors and the corresponding pixel values from the respective sub-images, and generating (135) the output image (145) by using the modified sub-images.

Abstract: The invention relates to a method and a system for modifying input images (101) for generating output images (102), said method comprising the steps of: splitting (103) said input images (101) into coarse images (104) and fine images (105), enhancing (106) the sharpness of said coarse images (104) for generating intermediate sharpness-enhanced images (107), combining (108) said intermediate sharpness-enhanced images (107) and said fine images (105) for generating said output images (102).

Abstract: A pixel relevance determining unit (100) for determining relevance values for respective pixels of an image is disclosed. The pixel relevance determining unit (100) comprises edge determining means (102) for determining a first edge orientation for a first one of the pixels (300) on basis of a first group of pixel values and for determining a second edge orientation for a second one of the pixels (308) on basis of a second group of pixel values, the second one of the pixels (308) being located in a neighborhood of the first one of the pixels (300); and assigning means (104) for assigning a first one of the relevance values corresponding to the first one of the pixels (300), on basis of comparing the first edge orientation with the second edge orientation.