基于FPGA的铁磁物质探测系统设计与研究

Design and Research of Ferromagnetic Substance Detection System Based on FPGA

铁磁性物质对磁共振成像质量、设备安全和相关人员人身安全有着巨大威胁。传统金属检测仪敏感度不同,容易变化且不能分辨被测物是否为铁磁性。国外专用铁磁探测系统性能优异但技术保密严格且价格昂贵,而国内检测产品在灵敏度方面与之相比不占优势。基于FPGA的铁磁物质探测系统设计根据磁通门传感器测磁原理,采用平行式线圈结构,通过基于数字正交锁相放大的二次谐波法对采集的信号进行数字信号处理并对其进行自适应滤波算法处理以提高系统整体性能。实验测试结果表明,该系统较模拟式信号处理抗干扰能力强且使得铁磁性物质探测的灵敏度提高10.3%,实际探测距离由0.5m提高到1m。

Ferromagnetic substances pose a huge threat to the quality of magnetic resonance imaging,the safety of equipment and the personal safety of related personnel.The sensitivity of traditional metal detectors varies easily and cannot distinguish whether the mea⁃sured object is ferromagnetic.The foreign special ferromagnetic detection system has excellent performance but strict technical confi⁃dentiality and high price,while domestic detection products do not have an advantage in terms of sensitivity.The design of the ferro⁃magnetic substance detection system based on FPGA is based on the principle of flux measurement of the fluxgate sensor,adopts a par⁃allel coil structure,and performs digital signal processing on the collected signal through the second harmonic method based on digital quadrature phase lock amplification and apply adaptive filtering algorithm to improve the overall performance of the system.Experimen⁃tal test results show that the system has stronger anti-interference ability than analog signal processing and the sensitivity of ferromag⁃netic substance detection is increased by 10.3%,and the actual detection distance is increased from 0.5m to 1m.