Research On High Precision Vision Inspection System

Modern science and technology tends to develop rapidly into small, ultra-precision fields.It develops from mm and micron level to nano technology. With Micro,Nano Technology rising , it has already caused the evolutional change ,such as manufacture material, biology, communication, national defence,bringing about huge influence on the living quality of human and society. With the continuous development of micro-technology, the characteristic of small-scale micro-mechanical has become an advanced technique of people knowing and reforming objective world from the tiny view angle. With enhancing of the industry manufacture technology and the machine process, people put forward of higher requests to the product's detecting approaches, detecting speed and detecting precision. But exiting inspection means can't give attention to either speed or inspection. But inspection's precision and efficiency decided the development of level of manufacturing and technology in some extent. So we must find a new inspection technique to resolve this problem. As a result, it brings a new technique——the technique of high accuracy of vision inspection.High accuracy of Machine vision inspection is a new technique based on modern optics in measurement area, and it is a modern test technique which includes optical electronics, computer iconography, information processing and computer vision etc. it regards picture as means and carrier of inspection and passing information and pick up useful information from picture and acquire all kind of parameter needly by deal with picture , vision examination technique's have many advantage ,such as no touch, all vision and high speed, it also has some advantage ,such as on line examination real time analyze , real time control. It is widely used in military industry, inspection of product ,high accuracy measurement , medicine and so on.Since the application of visual system has used from 1980s,it is ued very wide.The computer vision examination has obtained the vigorous development, the new concept, the new theory, the new method have unceasingly emerged, and it has been widely used in various fields.But In the domestic, the industry vision system still is in the conceptual phase.compared with overseas,the domestic computer vision examination research and the application level has 20 years disparity at least.So, in further exploring the theory and practice of visual inspection, absorbing advanced technology and academic thought, broadening the use of fields of visual inspection are very important.Combinging project of industry key scientific research(the project serial number: 2005B100014) of the NingBo city-- the research of small size measurement system based on machine vision ,The article has studied the examination principle and therealization method of the high accuracy vision examination system, and analyzed the primary factor of influencing system's precision, And proposed the way of increasing the system precision. Finally we taked stip as the examination object, and constructed the high accuracy examination system, and carried on the examination according to the technical requirements of testing components.The full text of main content as follows:This article discussed the general pattern of high-precision machine vision inspection system, the system works, given the hardware components of visual detection system,and detailed the selection description of the detection system hardware, stressed the importance of the software and analysis key technologies of influence the the precision of machine vision examination system.The main task of Visual detection system is image gathering,image processing. Images have been affected with error in the collection, transmission, processing process and so on, and these errors are inevitable. These seerrors will have a serious impact on the system accuracy until us analysis and processe to these seerrors.The papers analyzes the primary factor of influencing system's precision, and proposed the reduction or elimination of these error methods to improve the measurement accuracy of the system.Sub-pixel edge detection technology is a new development of image processing technology, and a high precision vision inspection technology. It occupies an important position in the field of vision inspection. Image Feature detection relates the ultimate success or failure of detection. Weather effectively extracting the necessary geometric features is the important of task of vision detection. The paper describes the concept of sub-pixel edge detection and explores the sub-pixel edge detection method which is used widly such as cubic spline interpolation and Curve fitting and so on.A method of Least squares curve-fitting interpolation based on the edge of a sobel method is proposed to improve the accuracy and computational speed of the edge detection. Hough transform is a traditional way which computational speed is lowly and positioning accuracy is not high. This paper also proposed a method of slope statistics based on the edge region to extract a straight line. Proposed a method of three points to extract the round and center of round makes the amount of calculation reduce and also makes detection more accurate. Experiments show that the methods proposed by paper have fast and high accuracy, and improve accuracy of the system effectively.The paper has constructed vision detection system of the clip, analyzed the detected task of clip and the detection principle, selected the appropriate hardware, and developed software of measureing parameter of clip, carried on examination on-line.it spends two seconds to measurement parameters for the entire testing period. The detection system has a very strong usability to many tasks which has very similar detection task and also has the bigger promoted value.