Thesis (Ph. D.)--University of Washington, 2000Ultrasound color flow systems are widely used in medical imaging because these are safe, noninvasive, and relatively inexpensive and displays images in real time. However to meet the real time requirement, these systems have been built with fixed function hardware, i.e., specialized electronic boards. This hardwired approach hinder the development of innovative algorithms to enhance the image quality and developing new applications to improve the diagnostic capability since incorporating a new application/algorithm is quite expensive, requiring redesigns ranging from hardware chips up to complete boards or some times even the complete system. On the other hand, a programmable system could be reprogrammed to quickly adapt to new tasks and offer advantages, such as reducing costs and the time-to-market of new ideas. Despite these benefits, a completely programmable color flow system that meets the real-time requirement has not been possible due to the limited computing power, inadequate data flow bandwidth or topology, algorithms not optimized for the architecture of programmable processors. This research has addressed these issues by developing a multiprocessor architecture capable of handling the computation and data flow requirements for a real-time system utilizing new generation VLIW processors, and by designing efficient ultrasound algorithms tightly integrated with the underlying architecture.These new generation VLIW processors can deliver increased computing performance through on-chip and data-level parallelism. Even with such a flexible and powerful architecture, to achieve good performance necessitates the careful design and mapping of algorithms that can make good use of the available parallelism. We developed several algorithm-mapping techniques for the efficient implementation of ultrasound algorithms utilizing both on-chip and data-level parallelism. We then designed a low-cost, high-performance multiprocessor architecture capable of meeting the realtime requirements of the ultrasound color flow system. To demonstrate this multiprocessor architecture and algorithms meet the real-time requirements, we developed a multiprocessor simulation environment with a board-level VHDL simulator. Our simulation results indicate that the two-board system with 4 MAP1000s on each board is capable of supporting all the ultrasound color flow system requirements. Thus, we have demonstrated that a fully programmable ultrasound system can be developed with the reasonable number of programmable processors
