基于图像处理的数显温度计在线检定系统设计

Development of an Online Calibration System for Digital Thermometers Based on Image Recognition

在数显温度计计量检定中,其发光二极管示值检定是其中一项重要的检定项目。利用恒温槽、二等标准铂电阻温度计、测温仪、CCD相机、条形光源和上位机搭建了基本的温度检定系统。根据JJG 1162—2019的检定要求,提出了一种基于图像处理的数显温度计示值检定方案,通过设计在线检定流程,利用CCD相机获取目标图像并上传至上位机,经过图像处理算法实现示值的自动识别与合格性判定,将示值识别结果与标准器数值比对实现数显温度计在线检定,通过实验验证,识别准确率可达96%以上。

In the metrological verification of digital display thermometers,the verification of its LED indication value is one of the important verification items.A basic temperature verification system is built by using thermostatic bath,second-class standard platinum resistance thermometer,thermometer,CCD camera,strip light source and upper computer.According to the verification requirements of JJG 1162—2019,a digital thermometer indication verification scheme based on image processing is proposed.Through the design of online verification process,the CCD camera is used to obtain the target image and upload it to the upper computer,and automatic recognition and qualification determination of indication values are achieved by image processing algorithms.The results of indication recognition are compared with the values of the standard to achieve online calibration of digital thermometer.Through experimental verification,the recognition accuracy can reach over 96%.