Study Of Coaxiality Measurement Based On Laser

Coaxiality measurement technology, which is also named axis centring technology, is mainly used to measure position deviations and angle deviations of rotarys' coupler. Rotarys have been widely applied in many fields such as machining, power generator, aerial equipment detecting. Whether the set of axes in these fields is centered has great influence on equipments' normal working. So coaxiality must be measured not only in the process of equipment installation but also in the process of current repair. Manual method and photoelectric method have some shortcomings, such as inefficiency, big man-made error and low-level automatization, so conventional methods do not meet the requirement in measurement of coaxiality. Computer vision inspection is a new technology based on modern optics, which syncretizes optical electronics, computer image, information processing, and computer vision. It has many advantages, such as non-contact, big field, high efficiency and high precision. It also has the ability of on-line inspection, real-time analysis and control. It is widely used in military industry, mechanism, electronics, agriculture, medicine and so on. Some principles and algorithms of computer vision inspection can be used to improve the efficiency and accuracy in measure system of coaxiality.Developing process in the field of coaxiality measurement was been researched and analyzed, and several methods which employed laser to measure coaxiality were introduced. The idea is put forward that the principles and algorithms used in computer vision inspection will be adopted in coaxiality measuring system. The situation and trend in development of computer vision inspection have been summarized.This paper described the measuring principle of the coaxial measurement system. A formula used to compute position deviations and angle deviations was.given This system is consisted of the hardware and software. A algorithm routine of video collection and multi-threaded sync were schemed out.Image processing is the kernel of computer vision inspection, and has great effect on accuracy and efficiency. In this paper, the basic concept of digital image is introduced, and some methods of image processing, such as image filter, image segmentation and edge detection, are discussed in detail. Based on basic image processing methods, the special image processing method, which include denoising through Wiener, segmentation through threshold, center calculating through improved method of computation of center of mass base on gray level, is designed in this measure system.The accuracy of coaxiality measurement system was been theoretical analyzed and experimental verified. The result indicates the system has excellent accuracy and repeatability.