Abstract: A new method to trace region contours and generate chain code tree was proposed by defining the vertex chain code and constructing the pixel vertex matrix of binary images. While tracing contours of a region and extracting vertex chain codes of these contours, the chain code tree of the contours is created. Further more, the complexity of the algorithm is linear and it can be used for tracing the contour of any complex region.

Key words: pixel vertex matrix, contour tracing, chain-code tree, vertex chain code, pixel vertex matrix, contour tracing, chain-code tree