Efficient Computerized-Tomography Reconstruction Using Low-Cost FPGA-DSP Chip

Abstract

In this paper, filtered back-projection algorithm is optimally implemented using low-cost Spartan 3A-DSP 3400 chip. The optimization enables parallel implementation. The combination of the pixel parallelism and projection parallelism is presented to significantly reduce the total reconstruction time to produce the image. The applied data is presented in fixed point format to achieve efficient implementation with maximum speed. The selection of data bus-width is optimized with very little error and good visual quality required for medical images. Before implementation, the computer tomography (CT) reconstruction simulator is developed to provide a testing reference for the hardware implementation. Using the combination of the pixel parallelism and projection parallelism, the presented hardware design achieves image reconstruction of a 512-by-512 pixel image from 1024 projections in 134.8 ms using 50 MHz clock cycles. It achieves the reduction of the required number of clock cycles to form an image from projections by 60 % comparing to the state of the art of the reconstruction time using field programmable gate array (FPGA) design.