Research Of Monocular Vision Measuring System Based On Coding Measuring Bar

With the rapid development of science and technology, the detection accuracy requirement in modern industrial production and processing equipment is getting higher and higher. At present, CMM are mostly very heavy and not meet the rapid measurement needs of large-sized work-piece in the site. In the large engineering projects such as aircraft assembly,engine blade measurement, the reverse engineering of car body, etc., moving the large-sized work-piece to a heavy CMM for its measurement is unrealistic. Obviously, the traditional CMM can't meet the requirements of field measurement, a more realistic approach is to build a portable high-precision coordinate measuring system in the engineering site, while the development of vision measurement technology has made up this defect. Vision Measurement technology has the advantages of high precision, large measuring range, rapid measuring speed, easy to install or carry and non-contact, etc, so it is wildly popular in the modern industrial detection field. It is also widely used many fields including aviation, aerospace,automotive and military.According to the research and analysis of the domestic and international vision measurement technology, combined with years of experience of our research group, this paper proposed a monocular vision measuring system based on coding measuring bar which can be set up at the test site and the measurement can be achieved by imaging the feature points of coding measuring bar.Firstly, this paper gives a detailed introduction of the construction of measurement system, mathematical modeling, solution of the mathematical model and the absolute positioning of the measuring head. Then, the errors of the measurement system are analyzed from different aspects and the corresponding compensation measures have been proposed.Finally, the system was tested by single-point repeatability test, the comparative experiment with the two-dimensional precision stage and the comparative experiment with the standard gauge block. The experimental results show that the accuracy of the system can meet the requirements of large dimension's measurement in industry, has a certain practical significance.