The Research Of Automatic Calibration System For Dial Instrument

The dial instruments are the primary tools for the measurement of electricity inelectric power industry. According to the regulations for the dial instruments, they mustbe calibrated periodically, but the instrument reading is not accurate in the classicalcalibration and the method is not efficient.The paper uses the technique of calibration with power source, the pointer of dialinstrument is derived by the power source, and the meter image is captured by thecamera. The technique of edge detection is used to position the meter edges and thescales area, and particle analysis is used in the detection of scales and pointer. The paperput forward a method called "point-arc projection" which is used to position the scales,and the least squares fit based on maximum likelihood estimate is used to position thepointer. Experiments show that the calibration system is fast, efficient and well worked,it can satisfy the need of calibration work in the industry.