A method and apparatus is provided for adjusting the contrast of an input image. A blurred image corresponding to the input image is obtained, the brightness level of at least some of the pixels in the input image being varied to provide the blurred image. A ring likelihood for pixels in the input image is obtained, the ring likelihood providing a measure of the likelihood that said pixels are non-edge pixels in the neighborhood of an edge pixel. The output image is produced as a sum of the brightness levels in the input image and the blurred image in dependence on the ring likelihoods.