Magnetic Sensor Array Based on Coordinate Measuring and Differential Evolution Algorithm

Positioning and tracking technologies have emerged as one of the key techniques for advancing the development of computer-aided medicine. To provide precise medical care, it is necessary to rely on high-precision magnetic positioning functions in medical application scenarios, such as capsule endoscopy and rehabilitation training detection. Due to the position and angle deflection of the magnetic sensor array during manufacturing and installation, there is a deviation between the measured magnetic field intensity of the sensor and the actual magnetic field intensity of the theoretical magnetic source. In this study, a calibration of coordinate measurement method was proposed and an optical plate calibration platform of $300\times450$ mm was developed. The 3-D coordinates of both the bottom surface of the magnetic source placement platforms and the three-axis magnetic sensors were measured with an optical image measuring instrument (NVC500) and a coordinate measuring machine (Daisy8106). The new method for sensor array calibration proposed in this study can be achieved by simply obtaining the sensor deflection angle and the sensor compensation coefficient. Without having to calibrate the sensor position, this method can obtain precise sensor position coordinates and the position and orientation of the calibration magnetic source. Finally, experiments were conducted to determine the association between magnetic source distribution and positioning accuracy, and the results could serve as a guide for the use of magnetic sensor array positioning.