A method of determining a saliency map (e.g., 900) for an input image (e.g., 600) is disclosed. Pre-determined data defining relative salience of image features is accessed. The input image (600) is decomposed according to the predetermined data to identify features of the input image (600) corresponding to the image features in the predetermined data. A portion of the predetermined data corresponding to a range of the identified image features is selected. A perceptual scale is determined using the selected portion of the predetermined data. The saliency map (900) for the input image using the determined perceptual scale.