Number of classes

Number of classes is usually given as an input variable. We have chosen 16 because it is a power of 2, and about the size that a human can visualize easily (more than 16 and the image starts to look cluttered).

There are sometimes good reasons to use a specific number of classes. You may be wanting to classify a scene into vegetation, soil and water, in which case 3 or 4 should suffice.

Or, you may want to display a 4 Million color image on a 256 color terminal. So you would cluster with 256 classes to do the mapping. Of course, color histogramming may be a more efficient way to do this. Clustering has the additional problem that some classes may drop out (see Dead classes ).



This page is maintained by Prof. Miriam Leeser
Last updated September 16, 1999.
Email: mel@ece.neu.edu