A Parallel Recursive Shortest Spanning Tree Algorithm for Image Segmentation in Distributed Computing Environment

The recursive shortest spanning tree (RSST) algorithm has been used for various image and video coding systems. The speed is very demanding for such applications. However, the RSST algorithm is too complex to perform in a reasonable time. This motivates the present work. A distributed algorithm that constructs a recursive shortest spanning tree for image segmentation with a fixed number of processors is presented in this paper. Using a tailored data partition strategy to assign jobs to processors in our proposed parallel recursive shortest spanning tree (PRSST) algorithm, we derive a new lower bound ofO(n) for one processor with ann-pixel image. The complexity of the proposed algorithm is cost-optimal and the total number of messages required isO(c) for images of any size, wherecis a small constant. The objective quality of segmented images produced by our PRSST has maximum 1.5 dB difference from those generated by Morris's RSST algorithm for images of the size of 128 by 128 and 150 by 150 pixels.