Semi-automatic watershed merging method

Watershed transformation frequently produces over-segmented images. The authors propose a solution to this problem. It utilizes hierarchical cluster analysis for grouping watersheds which are treated as objects characterized by a number of attributes. Initially the watershed merging method was meant only for gray-scale images, but later it was adapted for colour images. This paper presents further extension of the method that allows it to either automatically select the number of classes or to provide a hint as to which numbers in a specified range should be considered first. Segmentation quality assessment functions for colour images are presented. The results obtained using an extended watershed merging method are discussed. The examples of segmentations selected by the method, along with the graphs of assessment functions, are shown.