1. A method for filtering pixels in rasterized image data comprising a combination of text and photographic content, each pixel having a discrete color value, the method comprising the steps of: determining for each pixel as a current pixel a surround value based on a number of neighboring pixels having the same color value as said current pixel; dividing the pixels in blocks of two by two pixels; determining a first critical number for each block of pixels, based on a number of surround values lower than a predetermined surround threshold within each block of pixels; discriminating noisy blocks, wherein pixels have different color values, from flat blocks, wherein pixels have the same color values, based on the first critical number; replacing the color values of pixels within a noisy block by an average of the color values of the pixels within the noisy block.