FPGA-based Forward and Back-Projection Operators for Tomographic Reconstruction

摘要

Artifacts in computerized tomography (CT), such as metal streak effects, can also be reduced using the iterative reconstruction approach. The main issue in iterative method is the computation cost by efficient implementation of the forward and back-projection operations, which are the dominant cost in all iterative reconstruction algorithms. We designed a field programmable gate array (FPGA)-based operators for iterative forward and back-projection method to solve the artifact model. The projection method in CT reconstruction is to retrieve the volumetric image based on observed projection image and makes reconstruction errors minimize. The FPGA-based operators contain only the iterative reconstruction operations from tomographic projections, and the filtering of detector data and the geometry correction between detector and object are done by host CPU processor. For FPGA design, we used Impulse C package, C-to-FPGA tool including the use of streaming and pipelining for high performance. We evaluated the FPGA-based projection on Shepp-Logan phantom data with metal streak artifact. Simulation results show that the FPGA-based operators can reduce the computation time of iterative reconstruction, while still providing accuracy comparable to CPU or GPU-based reconstruction.