FPGA实现角膜变形信号峰值时刻检测的研究  

Research on FPGA Realizing Peak Time Detection of Corneal Deformation Signal

作　　者：杨成禹[1] 王琦[1] 毕伟权 肖作江[1] YANG Chengyu;WANG Qi;BI Weiquan;XIAO Zuojiang(School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022;Jilin Dongguang Precision Machinery Factory,Changchun 130013)

机构地区：[1]长春理工大学光电工程学院,长春130022 [2]吉林东光精密机械厂,长春130013

出　　处：《长春理工大学学报（自然科学版）》2019年第4期37-41,共5页Journal of Changchun University of Science and Technology(Natural Science Edition)

基　　金：吉林省科技厅重点项目(20180201025GX)

摘　　要：为了满足非接触式眼压检测技术获取高精度的角膜变形信号峰值时刻的需求,提出了一种基于FPGA的角膜变形信号峰值时刻检测系统的实现方案。该方案以EP4CE1芯片作为主控芯片,实现了对角膜变形信号的检测及调理、A/D转换、FPGA峰值检测以及SDRAM存储等功能。FPGA峰值检测采用了自顶向下的方法,依据功能划分为时钟分频、FIFO缓存、峰值检测以及ADC时序控制几部分。采用Verilog HDL语言编写阈值比较寻峰算法,采用Quartus II开发环境对各个模块集成的顶层设计文件进行综合,实现对信号的采集和处理等操作,并采用Modelsim进行了仿真验证。实现了对两次峰值信号的检测以及对应峰值时刻的提取,且不需采用传统峰值时刻检测电路的比较器及DAC电路部分,减少了硬件电路的设计。角膜变形信号峰值时刻精准度直接关系到眼压信号检测时刻的精度,系统的峰值检测精度可达到1μs,测量误差小于0.2μs。In order to meet the non-contact intraocular pressure detection precision of the acquired corneal modification demand signal peak time,the implementation of deformation of the cornea was proposed based FPGA timing signal peak detection system.The EP4CE1 chip was used as the main control chip to realize the functions of detecting and conditioning the corneal deformation signal,A/D conversion,FPGA peak detection and SDRAM storage in the scheme.A top-down approach was used in FPGA peak detection,which was divided into clock division,FIFO buffer,peak detection,and ADC timing control according to function.The detection of the two peak signals and the extraction of the corresponding peak time were realized;and the comparator and the DAC circuit part of the conventional peak time detecting circuit were not needed,thereby the design of the hardware circuit was reduced.The accuracy of the acquired peak time was directly related to the detection of intraocular pressure signal at that moment.The accuracy of the peak time of the corneal deformation signal was directly related to the accuracy of the detection time of the intraocular pressure signal.The peak detection accuracy of the system can reach 1μs,and the measurement error is less than 0.2μs.

关 键 词：FPGA 峰值时刻检测 寻峰算法 光电检测 角膜变形信号 

分 类 号：TN247[电子电信—物理电子学]