基于FPGA的偏振OCT双路信号处理系统

摘要

针对目前基于计算机的偏振OCT具有系统数据处理速度慢、不能实时显示等问题,设计了基于FPGA的偏振OCT双路信号处理系统.FPGA设计包含同步时序控制、正交解调和CORDIC运算三个模块.同步时序控制模块为系统的各器件提供同步控制信号,实现数据的实时处理和同步显示.正交解调和CORDIC运算模块对预处理后的干涉信号进行振幅解调和相位解调,获取反射率和双折射率数据,经USB接口送入计算机进行实时显示.对玻片、云母片和生物组织进行偏振OCT系统成像,对成像结果的分析验证了系统具有实时探测生物组织反射率和双折射率的能力.%In consideration of the deficiencies in a polarization-sensitive OCT system based on the computer, such as low data-processing rate, unachievable real-time display and so on, a FPGA-based dual-signal processing system of polarization-sensitive OCT was built. FPGA design consisted of three modules: synchronous sequential control, quadrature demodulation and CORDIC a-rithmetic operations. Synchronous control signals was provided by synchronous sequential control module for each device of the system to achieve real-time processing of data and simultaneous display. The interference signal followed by pretreatment was implemented by quadrature demodulation and CORDIC arithmetic operations to proceed amplitude demodulation and phase demodulation, the obtained data of reflectivity and birefringence was sent into the computer to achieve realtime display via the USB interface, the polarization-sensitive OCT experiment was designed by the paper to obtain two-dimensional image of cover slip, mica and biological tissue, after analyzing the result of experiment, the ability of real-time detecting in reflectivity and birefringence is verified.