1. A method of determining a high resolution depth map corresponding to an image of a scene, said method comprising: receiving the image and an input depth map corresponding to the image; selecting, from a window region about an image pixel of the image, a plurality of pixels having a substantially similar characteristic value as the image pixel; determining a reference depth value for the image pixel from depth values in the input depth map which correspond to each of the selected pixels; determining weights for each pixel within the window region based at least on a difference between a depth value corresponding to each of the selected pixels and the determined reference depth value for the image pixel; determining a refined depth value for the image pixel from a weighted sum of the depth values corresponding to each of the selected pixels, said depth values being weighted in accordance with the determined weights; and determining a high resolution depth map corresponding to the image from the refined depth value.