Distance transformation and skeleton for shape feature analysis

The distance transformation (DT) is one of the basic algorithm in image analysis and recognition. It is especially useful for shape feature description and analysis. The DT originated as a tool to determine the skeleton of a figure in the continuous space and was extended to a digitized picture later. Numerous researches following to those in the early stages revealed that the DT is both practically useful and of much interest theoretically in many different aspects of image processing.