1. A method of generating a hierarchical classifier on a computer system for classifying digitized data, comprising: determining a divergence measure of a node of the hierarchical classifier, wherein the node represents a set of digitized data; determining a splitting criterion based on the divergence measure, wherein if the divergence measure is below a threshold value, the splitting criterion comprises a divergence-based splitting criterion which maximizes subsequent divergence after a split, and if the divergence measure is about or above the threshold value, the splitting criterion comprises an information-based splitting criterion which minimizes subsequent misclassification error after the split; and dividing, based on the splitting criterion, the data at the node into at least two child nodes to form at least a portion of the hierarchical classifier.