A multi-stage segmentation method for images of skin lesions

We present an algorithm to identify skin lesions from the digitized colour images collected in a clinical study of malignant melanomas in early 1994. The algorithm consists of three steps: (1) a multi-stage median filter to suppress noise, (2) a process to compute the threshold values for the lesions and the background normal skin, and (3) a rule-based system to identify the lesions. Trying to make full use of the colour information, the first two steps of the algorithm work on the RGB planes. Then the three colour planes are re-combined before the lesions are identified in the last step.