1. A method of generating a super-resolution image by a processing device, the method comprising: up-scaling an input image to generate an up-scaled image; and modifying the pixel value of a first pixel of the up-scaled image by: generating a similarity value for each of a plurality of candidate pixels in said input image and/or in one or more further input images, the candidate pixels being chosen based on the position of said first pixel in said up-scaled image, the similarity value being generated by evaluating the similarity of a group of surrounding pixels of each of said candidate pixels with a group of surrounding pixels of said first pixel; selecting a first subset of said candidate pixels based on said similarity values; and generating the modified pixel value of said first pixel based on the pixel values and similarity values of said first subset of candidate pixels.