Optimized high speed pixel sorting and its application in watershed based image segmentation

Efficient sorting of image pixels based on their grayscale value is traditionally implemented using an algorithm based on distribution or counting sort methods. We show that an elegant alternative can be used which outperforms the traditional method both in terms of processing speed and main memory access. We discuss both theoretically analyzed and real-life performance results, and demonstrate the improvements that can be obtained when our algorithm is combined with a well-known watershed image segmentation method.