EFFECTIVE FEATURE CLASSIFICATION IN IMAGES

In general, the subject matter described in this specification can be embodied in methods, systems, and program products. A plurality of electronic training images that are each classified as displaying substantially pictures is obtained. A plurality of local image features in each of the plurality of electronic training images is identified. A plurality of weak classifiers are recursively applied to the local image features. During each iteration a weak classifier that accurately classifies the local images features is selected. After each selection of a weak classifier features that were misclassified by the selected weak classifier are given greater weight than features that were classified correctly by the selected weak classifier. For each selected weak classifier a hillclimbing algorithm is performed to attempt to improve the weak classifier. A strong classifier that is a weighted combination of the selected weak classifiers on which hillclimbing algorithms have been performed is produced.