The Research Of Measurement System For Taper Threads Based On Photoelectricity

Lots of the products involved with threads have been applied in industry. The demand for threads'quality is always escalating in order to match the current design of industrial product. However, the methods for the measurement of threads have not been improved outstandingly in the 20th century. The rapid development in the modern photoelectric measurement method makes it possible that the measurement of threads becomes more automatic, intellectualized with higher precision recently.Using CCD to acquire images, using the image processing technology to obtain the required parameters has been widely applied in all kinds of measuring fields. In the research, a new automatic instrument based on image measuring technology for the parameters of taper threads has been designed. Through the analysis of the three ball methods, a novel method that can measure the taper thread's diameter with virtual balls is presented with the character of image measuring technology. The thesis has deduced its merits theoretically.Then the mechanism system is designed. The function and relations between components are explained according to the demand for instrumental precision. Using finite element method analysis, the design of main deformed components, upright column and optical base plate, are optimized to meet system's rigidity. The image-forming system design completed in the thesis is based on infinite image distance optics theory.The research emphasizes the technology about edge location. Several traditional methods for edge detection, edge fitting and subpixel operator, are compared so as to select the appropriate one. The Canny operator has been improved to fit for practical thread images. The Hough Transition has been implemented to obtain the count of lines automatically. Finally, edge lines are fitted by the least squares technique, after filtering the points with bigger variance. Using above methods, the man-machine interactive software has been developed for obtaining the required parameters.The tools for calibration have been designed to match the mechanism of system. The process for calibration has been realized in the software and the...