In this paper we present a method for learning classspecific
features for recognition. Recently a greedy layerwise
procedure was proposed to initialize weights of deep
belief networks, by viewing each layer as a separate Restricted
Boltzmann Machine (RBM). We develop the Convolutional
RBM (C-RBM), a variant of the RBM model in
which weights are shared to respect the spatial structure of
images. This framework learns a set of features that can
generate the images of a specific object class. Our feature
extraction model is a four layer hierarchy of alternating
filtering and maximum subsampling. We learn feature
parameters of the first and third layers viewing them as separate
C-RBMs. The outputs of our feature extraction hierarchy
are then fed as input to a discriminative classifier. It
is experimentally demonstrated that the extracted features
are effective for object detection, using them to obtain performance
comparable to the state-of-the-art on handwritten
digit rec...