Automatic Verification System Of Pointer Pressure Gauge Based On Visual Detection And Camera Positioning

At present,because of the simple structure and huge number of pointer instruments,the application of pressure gauge is the most common.When calibrating pointer pressure gauges,manual reading of records is usually used,which consumes a lot of manpower,is inefficient,and has large reading errors.Therefore,it is urgent to use automatic verification methods and systems.The implementation of automatic calibration of pointer pressure gauges mainly involves issues such as pointer indication and its range,automatic recognition and reading of standard digital instrument values,and there is also a situation where the instrument panel and camera lens are not aligned,resulting in reading errors in pressure indication values.In view of such problems,conducting research on the automatic calibration system for pointer pressure gauges plays an important role in improving the quality and efficiency of pointer pressure gauge calibration work and promoting industrial and agricultural safety production.The main research content and results are as follows:Firstly,carry out research on the automatic calibration method of pointer pressure gauges.According to the requirements of national verification regulations for pointer gauges,based on machine vision detection and camera automatic positioning technology,by treating the automatic reading of the certified pressure gauge and the standard digital pressure gauge,the calibration error of the pressure gauge is calculated and processed,and the automatic verification work of the pointer pressure gauge is realized.The key technology of the research includes two aspects: The first is a threedegree-of-freedom mechanical transmission technology based on one-dimensional rotation and two-dimensional movement,the research and establishment of the threedegree-of-freedom automatic positioning correction method of the camera;The second is the digital dial and pointer scale image processing technology,research and identify the pressure gauge pointer position,calculate the indicator value of the pressure gauge;Using template matching and OCR training algorithm,the measuring range of pressure gauge is identified with the indicating value of digital standard pressure gauge.Secondly,carry out the design of an automatic calibration system for pointer pressure gauges.Combined with the structural characteristics of the certified pointer pressure gauge and digital standard pressure gauge,a low cost automatic verification device for pointer pressure gauge is designed by using two industrial cameras and three degrees of freedom mechanical transmission platform.Based on NI data acquisition card,PC and Lab VIEW development platform,the automatic verification and control system of pointer pressure gauge is designed.It mainly includes camera automatic positioning and correction,image acquisition and processing hardware,as well as pointer pressure gauge range,pointer scale and digital standard pressure value machine vision recognition software,automatic verification software,etc.Finally,carry out the construction and application experiments of the automatic calibration system for pointer pressure gauges.Analysis of the test results shows that:When the camera is automatically positioned,the Angle error with the actual dial is less than 1.2°;The reference error of the automatic verification system of pointer pressure gauge and the manual reading value is less than 0.364%,which meets the calibration reading error requirements of the verification regulations;The automatic verification time is 5min,which is more than 50% shorter than manual verification time.