With advances in technology and the declining cost of computer hardware, it is now feasible to design computer architectures consisting of large numbers of processors executing programs concurrently. Most parallel computing architectures can be generally classified into SIMD and MIMD systems. SIMD processors simultaneously and synchronously execute the same instructions on different data streams, while MIMD processors are not necessarily synchronous and execute different instructions on different data streams. In image processing, for example, low level tasks generally have an image as input and image as output. SIMD systems well suit these tasks, and most existing parallel image processing systems are of this type. An important part of a parallel processing system is the interconnection needed for the transfer of information among processors, and between processors and memories. In such systems several processors may need data from memories or other processors simultaneously; therefore, the network should be capable of providing fast parallel access to data. The interconnections designed for use in multiprocessor systems range from a common bus to a crossbar network.