基于磁通门传感器的铁磁探测系统设计

在核磁共振检查前需要进行无磁化确认，针对核磁共振检查所处的环境背景磁场复杂、干扰较多，系统出现误报警高、探测失效等问题，设计了基于磁通门传感器的铁磁探测系统。系统使用二次谐波法测量磁场信号，设计模拟电路进行信号相敏检测。通过积分反馈提高闭环系统的线性度和抗干扰性，探头工作在稳定的状态。采用卡尔曼滤波对背景磁场和磁异信号进行处理，提高信号信噪比，同时设计能量检测器对磁异信号进行检测。试验测试结果表明，系统在核磁共振室外复杂磁场环境可以减少设备工作时的误报警，有效探测出铁磁性物质。

Design of ferromagnetic detection system based on fluxgate sensor

No magnetization confirmation is required before the magnetic resonance imaging. In view of the complex background magnetic field and large interference in the environment where the magnetic resonance imaging equipment is located, the system has problems such as high false alarm, detection failure, a ferromagnetic detection system based on fluxgate sensor is designed. The system uses fluxgate sensor and second harmonic method to measure magnetic field signal, and the analog circuit is designed for phase sensitive detection. The closed-loop system improves the linearity and anti-interference through integral feedback to make the probe work in a stable state. Kalman filter is used to process the background magnetic field and magnetic anomaly signal to improve the signal-to-noise ratio, and the energy detector is designed to detect the magnetic anomaly signal. The test results show that the system can reduce the false alarm when the magnetic resonance imaging equipment is working in the complex magnetic field environment outside the magnetic resonance imaging room, and effectively detect ferromagnetic substances.