Load balancing for a class of irregular and dynamic problems: region growing image segmentation algorithms

This paper discusses and evaluates a parallel implementations of a segmentation algorithm based on the Split-and-Merge approach. The solution has been conceived for a multiprocessor using the SPMD (Single Program Multiple Data) programming model and executions have been carried out on a Cray-T3E system. Our main goal is intended to describe our experiences in solving the region growing problem, which is representative of a class of non-uniform problems, characterized by a behavior that is data dependent. Since this problem exhibits unpredictable load fluctuations, it requires the use of load balancing schemes to achieve efficient parallel solutions. We also propose and analyze several strategies for the selection of the region identifiers and its influence on the execution time and the load distribution.