Labeling board based on boundary tracking

This paper reports on hardware implementation of a labeling algorithm using a combination of raster scanning and boundary tracking. For the prototype board, a new method is employed for generating addresses of image memory so that boundary tracking is efficient. Since boundary tracking is used, there is no need for working memory for storage of initial labels. Hence the circuit becomes compact, and the labeling can be performed without restricting the number of labels. Furthermore, it can also count the number of holes when labeling and it can set the minimum or maximum boundary length of the region to be labeled. This board is constructed using only general purpose ICs; for a 512 × 512 image, the processing time is approximately 50 ms.