Communication control in a pyramid computer-application to region labeling

A type of pyramidal graph which is a special subgraph of the pyramidal network and is designed to control data propagation through the pyramid is defined. A set of image objects (edges, regions, etc.) stored in an image, one pixel per processor in the bottom layer, is represented by a smaller set of processors spread on the pyramid and computed dynamically from the image by bottom-up algorithms involving uniform and efficient communication. A set of communication/computation primitives is defined between image objects and their representative processors. These tools are applied to a fast region-labeling algorithm. Experimental results are presented to evaluate the behavior of these very data-dependent algorithms