1. An apparatus for enhancing at least a region of an input picture having input pixel values, comprising: an estimation unit arranged to identify the region of the input picture based on an estimate of a quantization precision; a pattern analysis unit, arranged to identify positions in the input picture of changes in input pixel value of less than or equal to the quantization precision, and to output analysis information representing the identified positions; and an adaptive filter, arranged to calculate an output picture corresponding to at least the region of the input picture, comprising output pixels being determined on the basis of adaptive combinations of input pixels, and arranged to determine the adaptive combinations in dependence on the analysis information, wherein the estimation unit is arranged to determine the quantization precision on the basis of a histogram of at least a second region of the input picture.