3d Tomography Back-Projection Parallelization On Fpgas Using Opencl

This paper deals with the evaluation of FPGAs resurgence for hardware acceleration applied to computed tomography on the back-projection operator used in iterative reconstruction algorithms. We focus our attention on the tools developed by FPGAs manufacturers, in particular the Intel FPGA SDK for OpenCL, that promises a new level of hardware abstraction from the developer's perspective, allowing a software like programming of FPGAs. For this purpose, we start with evaluating different custom OpenCL implementations of the back projection algorithm. With some clues on memory fetching and coalescing, we then further tune designs to improve performance. Finally, a comparison is made with GPU implementations, and a preliminary conclusion is drawn on FPGAs future in computed tomography.