摘要
针对低场磁共振成像(MRI)系统,提出一种实用的基于通用浮点DSP的全数字高精度、高效率信号接收算法.对经前端调理的回波信号直接采样数字化,在通用浮点DSP上进行数字正交解调,采用高效的积分梳状滤波器(CIC)、半带滤波器(HB)、FIR滤波器等进行多级滤波抽取,极大的减少了运算量,提高了运算效率,最后得到用于成像的原始数据.整个数字信号处理过程全部采用单精度浮点数据格式,用软件实现,提高了运算精度,增加了信号检测系统的灵活性.最后通过CCS2.2软件仿真,验证了本算法的实时性和实用性.
Receiver plays an extremely important role in a magnetic resonance imaging system as it's precision and stability directly determine the qualities of the images obtained. In this study, an all-digital receiving algorithm based on general floating point DSP was developed for low-field MRI systems, and shown to be highly precise and efficient. Amplified echo signal was first directly digitalized, and then sent to DSP where digital quadrature demodulation, filtering and decimation were carried out. Cascaded data filtering was done with filters with high computational efficiency including integrator-comb filter (CIC), half band filter (HB) and equiripple FIR filter. Single precision floating point format was used in the whole process so that high precision and large dynamic range were maintained. The algorithm developed was implemented with a DSP program in ANSI C and inline assembler. Simulation on CCS2.2 proved that it can be used for real time detection and meets the requirements for practical use.
出处
《波谱学杂志》
CAS
CSCD
北大核心
2005年第2期187-193,共7页
Chinese Journal of Magnetic Resonance
