AC current online calibration device based on digital image recognition and fiber optic sensor

In situations using small alternate currents, for example, small signal transmission and measurement, the problems of measurement error due to current leakage and fluctuation, and many sensors using AC currents that do not reserve enough calibration interfaces are inevitable. In view of these problems, this paper designs an online calibration device for AC current. The device is based on digital image recognition technology and fiber optic current sensor technology, taking the fiber-optic current sensor as the standard to compare real-time numbers displayed by Hall current sensor. The image recognition technology uses a CMOS image sensor to collect the data displayed on Hall current sensor, and then uses digital image technology such as grayscale conversion, median filtering, binarization, and closed operation for preprocessing. Finally, the sampling value of the Hall current sensor obtained in the host computer will be compared to the standard measurement value obtained by the fiber-optic current sensor, and the measurement error with the controlled Hall current sensor will be calculated.