Development Of Control System For Automatic Verification Device Of Glass Gauge Based On Image Recognition

In the traditional glass gauge test,the capacity of the glass gauge is verified by manual measurement.This method has a large influence on human error,does not have good repeatability and requires manual recording of balance quality and temperature.There is a risk of error,measurement efficiency and accuracy are relatively low,and it cannot meet the requirements of calibration institute for verification accuracy and efficiency.With the increasing demand for metrology institutes,this contradiction has become increasingly prominent,and the highprecision and automated verification of glass gauges has far-reaching significance.Automated verification of glass gauges relies mainly on machine vision,which uses machines instead of human eyes for measurement and judgment.At present,the application of machine vision at home and abroad is mainly concentrated in the fields of industry,agriculture,national defense,transportation,medical care and so on.However,in the metrology industry,the application of machine vision inspection technology is almost blank.In this paper,the pipette and burette are taken as the research object,and the image processing algorithms such as grayscale,binaryzation,open operation and Hough transform are used.Through the experimental data analysis,the pixel variation law of the concave liquid surface is studied.The corresponding concave surface recognition method is adopted.On this basis,the hardware control system and the host computer software of the verification device are designed.The specific research contents are as follows:In-depth analysis of the JJG 196-2006 Common Glass Gauge procedures in the measurement method verification process,the construction and planning of the overall program of the device,determine the function of the device,the use of a system-oriented approach to the development of the entire device,in the analysis of the basis of demand.On clear functional planning,completed the overall hardware framework design of the device.According to the overall scheme,the STM32 single-chip minimum system,RS-485 communication system,pumping and draining control system,horizontal and vertical position control system,water temperature acquisition system,weighing system and air leakage prevention system are designed.On the basis of the hardware system,the top-down PC software design method is adopted,and the multi-task concurrent execution mode is adopted to give full play to the performance of the host computer multi-core CPU.Based on the MFC framework,the RS-485 communication module,information input module,parameter setting module,image processing module,data saving module and PID control module are developed.The automatic calibration function of the glass measuring device can be realized,and the Excel table export of the verification result is supported.The hardware control system is integrated with the upper computer system,and an experimental platform is built to debug the whole system.The experimental results show that the device has perfect function,reliable and stable operation,and can complete the automatic verification of 1ml-25 ml pipette and burette.The verification process meets the requirements of JJG 196-2006 common glass gauge.The accuracy of liquid level recognition is as high as 0.1mm,which can meet the requirements of the calibration mechanism for measurement accuracy.