Research On Key Technology Of DMMS Automatic Calibration System

This paper designed a set of automatic calibration system for digital multimeter. For Multimeter which with Data interface, take GPIB-interface and GPIB-card to control DMM and Calibrator. For Multimeter which without Data interface, take camera and OCR technology to get it’s display values. This paper’s innovation and work is as follows:1.New algorithms are introduced in the image preprocessing and location of LCD. Spiking neural networks, which inherit the parallel mechanism from biological system, are used to obtain the edge of images. Gray projection, expansion and hole filling approach to locating the areas of morphology’s display area. This location method with high accuracy strong anti-interference ability.2.1nnovative designed a thresholds dynamic binarization algorithm of LCD image recognition. Using methods based on wavelet transform to eliminate uneven illumination before binarization processing. Considering overall image and local feature information, improving dynamic threshold binarization method, designed three different thresholds to handle image, which ensures accuracy binarization algorithm.3.Innovative design XML configuration management techniques. Software systems using XML files to configurating projects, calibration points, calibration range and calibration parameters. It using XML files, configuration verification projects election, calibration points the selection, calibration, calibration range of commands and information such as calibration parameters. It is better than general detecting system and can meet the calibration requirements of various models and a variety of specifications digital multimeter.