A memory-efficient parallel single pass architecture for connected component labeling of streamed images

In classical connected component labeling algorithms the image has to be scanned two times. The amount of memory required for these algorithms is at least as high as for storing a full image. By using single pass connected component labeling algorithms, the memory requirement can be reduced by one order of magnitude to only a single image row. This memory reduction which avoids the requirement of high bandwidth external memory is essential to obtain a hardware efficient implementation on FPGAs. These single pass algorithms mapped one-to-one to hardware resources on FPGAs can process only one pixel per clock cycle in the best case. In order to enhance the performance a scalable parallel memory-efficient single pass algorithm for connected component labeling is proposed. The algorithm reduces the amount of memory required by the hardware architecture by a factor of 100 or more, for typical image sizes, compared to a recently proposed parallel connected component labeling algorithm. The architecture is also able to process an image stream with high throughput without the need of buffering a full image.