A combinational algorithm for connected-component labeling and Euler number computing

Connected-component labeling and Euler number computing are two essential processing tasks for extracting objects' features in a binary image for the pattern recognition, image analysis, and computer (robot) vision. In general, the two processing tasks are usually executed independently by different algorithms in different scans. This paper proposes a combinational algorithm for labeling connected components in a binary image and computing the Euler number of the image simultaneously. In our algorithm, for the current pixel, the two processing tasks use the same information obtained from its neighbor pixels in the same scan. Moreover, the information obtained during processing the current pixel will be used for processing the next pixel. Our method is simple in principle and powerful in practice. Experimental results demonstrated that our method is much more efficient than conventional methods on various kinds of images, either in the case where the Euler number is calculated alone or in the case where both connected-component labeling and the Euler number computing are necessary.