1. A method of processing an image, comprising: receiving digitized data representing an image, the image data comprising a plurality of pixels; segmenting the pixel data into segments at a plurality of scale levels; determining feature vectors of the segments at the plurality of scale levels, the feature vectors comprising one or more measures of visual perception of the segments; determining one or more similarities, each similarity determined by comparing two or more feature vectors; determining, for each of a first subset of the segments, a first measure of probability that the segments is a member of an object class; determining probability factors based on the determined first measures of probability and similarity factors based on the determined similarities; and performing factor graph analysis to determine a second measure of probability for each of a second subset of the segments based on the probability factors and similarity factors.