The invention relates to upscaling of images such as upscaling of video images from standard definition to high definition. An input image is upscaled to a resolution enhanced image (207) by weighting pixel values in the input image depending on a match metric combining two match metrics. A first image generator (103) generates a blurred version of the input image and a second image generator (103) generates an upscaled 5 interpolated version. The first metric is generated bycomparing pixel sets of the blurred image and the upscaled interpolated image. A second metric is generated by comparing pixel sets of the input image and already synthesized pixel values of the resolution enhanced image (207). For each location in a search area, a resolution enhancement processor (107) generates the combined match metric and uses this to weigh the pixel value of that location when 10 generating the unknown pixel value of the resolution enhanced image (207).