Fast Connected Component Labeling Using Run Information

This paper proposes two methods for connected component (CC) labeling with run-based way in binary images. In one method of the two, called method A, a binary image is transformed into run representa tion, and then each run is labeled in raster scan order. Labeled runs are transformed into a label image, finally. Labeling in raster scan order produces equivalent labels. We use the union-find algorithm with path compression and weight balancing for equivalent label maintenance. In another method, called method B, transforming of a binary image into runs and labeling of runs proceed simultaneously in raster scan order. The method B has a merit of saving memory space because only current two lines are required as run infor mation. In the general case where both of input binary images and output label images are two-dimensional array representation, both of proposed methods are faster than the pixelwise CC labeling standard metho d and run-based label propagation methods.