1. A method of extracting features in a picture for picture processing, comprising: determining representative data vectors based on a tolerance distance that represents data vectors in a class of vector spaces that define the picture to extract representative features of the picture for picture processing; wherein extracting the features comprises extracting dominant colors in the picture; wherein extracting the dominant colors further comprises: computing the tolerance distance that represents the data vectors in the class of vector spaces of the picture; forming a window based on the tolerance distance; computing a sum of data vectors using the data vectors falling within the window for each of a predetermined number of color values; comparing each computed sum of data vectors to a threshold value; and determining the representative data vectors to extract the dominant colors in the picture based on the outcome of the comparison.