Representing an image includes extracting information reflecting one or more characteristics of an image that then is used to compute a first histogram vector. The first histogram vector includes one or more vector elements, each representing information for a different characteristic extracted about the image. Multiple subsets are identified within at least one of the vector elements included in the first histogram vector and a second histogram is created. The second histogram vector includes a...

One embodiment of the present invention provides a system that deposterizes a posterized image. During operation, the system receives a posterized image, wherein pixels in the posterized image have color values that belong to a set of posterized color values, which is a subset of a set of possible color values for the deposterized image. Next, the system generates a deposterized image from the posterized image, wherein color values in the deposterized image are not restricted to the set of poste...