1. A method, performed by one or more processors, for increasing dynamic range of original image data representing an image, the method comprising: applying, by the one or more processors, an expansion function to generate, from the original image data, expanded data having a dynamic range greater than that of the original image data; obtaining, by the one or more processors, an expand map comprising data indicative of a degree of luminance of regions within the image and associated with pixels in the image, wherein obtaining the expand map comprises processing at least one of the original image data and the expanded data to thereby obtain the expand map data and wherein, for each region within the image, the degree of luminance of the region indicated by the expand map data is based on values of a plurality of pixels in the region; and, combining, by the one or more processors, the original image data and the expanded data according to the expand map to yield enhanced image data.