Parallel algorithm for quadtree medial axis transform

The quadtree medial axis transform (QMAT) representation of a binary image is a very useful scheme for computer graphics and image processing applications. We present an efficient algorithm for QMAT on the shared memory EREW-PRAM model. For an image of size n×n, using n×n processors, we compute QMAT in O(log n) time. Since image sensors provide image data as a two-dimensional array, a mesh connected computer (MCC) is a popular architecture for image processing applications. Previously known parallel algorithms for QMAT require O(log² n) and O(log n) time on a pyramid model, and a simulation of these two algorithms takes O(n log n) time on an MCC. However, our algorithm can be executed on an MCC in O(n) time, which is optimal for that model due to the size of its diameter