A high-speed algorithm for propagation-type labeling based on block sorting of runs in binary images

A fast algorithm for component labeling of binary images is proposed. Component labeling is an important method for separation of objects in document image understanding, especially in character and picture extraction. The proposed algorithm is based on sorting and tracking of runs and label propagation to the connected runs. Each scan line is partitioned into small segments, i.e. blocks and runs on the scan line are sorted according to the block sequence to speed up tracking of runs. It was ascertained by experiment that the processing time is 16.7 times faster than that of the conventional pixel-based labeling method