Parallel Thinning on a Distributed Memory Machine

A p a r a l l e l th inning algor i thm based on boundary fo l lowing i s presented i n t h i s paper. The boundary o f each object region i s extracted and l inked i n pa ra l l e l . The resu l t ing object boundary data i s div ided based on the object s ize and the nurrber o f nodes f o r load balancing, then the divided objects are red is t r ibu ted t o the nodes. Each boundary i n a node i s projected on a Ilworking planell. Next, the boundary data i s repeatedly shrunken unti l only the skeleton o f the region remains. The conventional i t e r a t i v e pa ra l l e l algori thm as wel l as our new algor i thm are implemented on a hypercubetopology multiprocessor computer, the I n t e l iPSC/2. The two algorithms are compared and analyzed. Some resu l t ing f igures and execution times are presented.