Classification using intersection kernel support vector machines is efficient

Straightforward classification using kernelized SVMs requires evaluating the kernel for a test vector and each of the support vectors. For a class of kernels we show that one can do this much more efficiently. In particular we show that one can build histogram intersection kernel SVMs (IKSVMs) with runtime complexity of the classifier logarithmic in the number of support vectors as opposed to linear for the standard approach. We further show that by precomputing auxiliary tables we can construct an approximate classifier with constant runtime and space requirements, independent of the number of support vectors, with negligible loss in classification accuracy on various tasks. This approximation also applies to 1 - 2 and other kernels of similar form. We also introduce novel features based on a multi-level histograms of oriented edge energy and present experiments on various detection datasets. On the INRIA pedestrian dataset an approximate IKSVM classifier based on these features has ...

• Type: Conference
• Year: 2008
• Where: CVPR
• Authors: Subhransu Maji, Alexander C. Berg, Jitendra Malik
• Keywords: Approximate Classifier, Approximate Iksvm Classifier, Chrysler Pedestrian Dataset, Computer Vision, CVPR 2008, Inria Pedestrian Dataset, Intersection Kernel Svms