The Research And Application Of Automatic Recognition For Analog Measuring Instruments

The automatic recognition technology of analog measurement instruments is very important for automatic calibration devices, it is also the key technology of integrating the Analog measurement instruments into digital systems. This thesis expatiates how to recognize the reading of analog measurement instruments by using machine vision technology. And a simple analog measurement instruments calibration system is researched.In the attainable correlative papers, the way of recognizing the reading of analog measurement instruments is as follows: Processing the image into a binary image and thinning the image, picking-up the pointer and scales with Hough transform, and calculate the recognition result from the angle relationship between pointer and scales. But the result calculated from angle relationship is not precision. The automatic recognition system is not mentioned oftenly. High precision in the automatic recognition of analog measurement instruments is needed. This thesis did something as follows:1. Research the automatic calibration system for analog measurement instruments.Design the hardware and software of the system. The hardware includes a camera, illumination establishment, programable standard source. A programable current source is designed as a standard source. The software includes contral program, image processing program and automatic recognition program.2. Research the methods of improving reading precision.Use light insulater and multi-aperture light source to improve the quality of images. Improve Otsu approach to turn a color image into a binary image. Pick-up the pointers and scales from binary images. With the help of distance relationship between pointer and scales, get a more precise reconition result.3. Realize the automatic calibration system. Good effect datas is acquired from the experiment of the automatic calibration system. The calibration system accords with requirements of relative rules.