Fast Measurement Technology Of Workpiece Sizes Based On Vision Detection

As the rapid development of opt-electronic technology and image processing technology, vision measurement gradually develops to be an modern scientific technology, and more involved in many domains of engineering application, with its advantages of non-contact、high-accuracy and efficiency.Workpiece size measurement also plays an important role among the measurement of modern industry. With high edge extraction accuracy and strong universality, the typical edge extraction algorithm, as an important part of image process system, is widely applied in workpiece sizes detection system based on Vision Measurement. However, a lot of applications prove that the algorithm is too complex to be efficient, especially when working on the images with simple outline. Therefore, according to low efficiency of typical edge extraction algorithm, we designs a fast measurement technology of workpiece sizes measurement based Vision Detection, taking detection into a kind of commonly-used tubular workpiece with simple outline.In this paper, firstly, according to the feature of the workpiece with highly reflective surface, we design LED back lighting source with uniform scattering. Secondly, the image preprocess is analyzed; according to the simple edge characteristics as well as high contrast of the workpiece image, the edge extraction approach, combining with threshold segmentation and edge tracing, is designed to fast extract the edge. Thirdly, after pixel-level feature points is picked up under second curvature method, with the help of the character that the feature point is the center point of the arc joining the adjacent edge line as well as grey moments sub-pixel technology, the sub-pixel level feature points is extracted. Finally, the workpiece calibration is made, the detection result is presented and the cause of the error is analyzed.In this paper, the dimensional measurement system for workpiece with simple geometrical shape based on the vision measuring technology could accurately measure the certain size information. Experiment approved, the system in the paper could meet the requirement for measuring accuracy with high measuring efficiency. The design could provide important reference for similar design for measuring the workpiece with simple outline as well as highly reflective surface.