On minimum cross-entropy thresholding

Over last few years several papers have been written on entropy-based thresholding. Some of these methods use the gray-level histogram, while others use entropy associated with the two-dimensional histogram or the co-occurrence matrix. Recently, Li and Lee proposed a thresholding scheme that is aimed to minimize the cross entropy. This note first points out a certain conceptual problem and then proposes two algorithms which are free from that problem. The proposed schemes are tested on several data sets. The results are encouraging.