The Research Of Digital Instrument Automatically Calibration System Based On Image Recognition

Digital instrument play a vital role in the field of safety monitoring,to ensure the normal monitoring function,people need to calibrate the digital instrument regularly.This paper first analyzes the current situation of digital instrument calibration, points out that the complexity of manul instrument calibration in reality,then using a calibration method based on source to design a overall scheme of the digital instrument automatic calibration system,meanwhile analyzes basic functions of the system, introduce the image acquisition module,the standard source control module,and the image processing module briefly,include using CCD camera and PCI data acquisition card to build the image acquisition system,using the mature standard source control technology to realize the standard contrast in digital instrument calibration;then,in the the platform of VC and OpenCV,do a research on digital instruments image that transported to the computer memory through image acquisition card,and using the method of difference inter-frame image preprocessing and accumulation to realize the coarse positioning of digital instrument display area,and introducing the rotating projection tilt method to correct the digital instrument display area,and proposed to achieve precise positioning of digital character region by using the method of adaptive threshold and line scanning,and then using vertical projection method to achieve segmentation of number character that the upper and lower boundary have been positioning,finally choosing the template matching method to recognize the digital characters,including using the threading method to extracte feature of digital character after normalization and thinning,and a modified Euclidean distance to realize the matching recognition of digital characters,the recognition problem has been solved finally. In practical application,the automatic calibration system of digital instrument based on image recognition realize accuracy and also has a high real time,can meet the needs of verification department.