The Pointer Instrument Of Automatic Verification System

In this dissertation, researchs are done for auto-detecting of the gauge with pointer which plays an important role in industrial detecting at present. But, usually, detecting of the gauge with pointer is by manual work, after long time for vision work, eyes will get tired, and this leads to low detecting precision and long detecting period.An auto-detecting method of the gauge with pointer that is based on digital image processing technique, high precision grating technique and step motor control technique is presented. There are advantages of high precision, high efficiency and auto-detecting for apply digital image processing technique to detect precision of the gauge with pointer; moreover, it's helpful to improve system's resolution when high precision grating technique is applied to measure micro displacement; also it makes system more automatic to control step motor in computer via step motor control card.The design of step motor control card is based on DSP technique and PCI bus technique. Compared with traditional technique of step motor control based on MCU, we can implement movement control algorithm quickly with DSP technique. In many detecting instruments of the gauge with pointer, computer controls motor via RS232 serial port, which is a problem if we need control motor more quikly. This card which realizes communication between computer and DSP with high-speed PCI bus technique improves control speed of motor, so as to improve the real-time quality of system.This system provides pulse signal and direction signal to step motor driver by computer's controlling step motor control card, and makes motor and guage's pointer rotate. Computer gets the micro displacement measured by grating measuring system via RS232 serial port, and acquires guage's image by high precison CCD camera, then processes the guage's image by software, including pre-processing, graying, binarization, thinning and Hough transform, so as to recognize the position of guage's pointer, finally calculates all kinds of precision on basis of algorithm established by National Detecting Rules of Gauges. The speed of algorithm of image processing adopted in this system is fast, which improves system's real-time quality.Control of system is completely operated in the platform of Windows. The...