1. A computer-implemented method in which a computer system performs operations comprising: building a first model using a positive data set; building a second model using a negative data set; and using linear programming, distinguishing said first model from said second model to determine a set of features that make the object stand apart from rest of image data for a filter for use as an image classifier and wherein said using linear programming comprises using the minimization formula arg ⁢ ⁢ min β - tr ⁡ ( X T ⁢ Y ⁢ ⁢ β ) where X is a collection of vectors from a data source, Y is a collection of features, and β is a selector matrix of features in X using the determined features to classify an image.