Study Of Engine Camshaft 3-D Measuring Method Based On Computer Vision

As a classic long shaft, Engine camshaft is a very important part in a car. It acts for motivating the whole timing system and other accessories and letting them take in and send out oil air fast and accurately which can assure a right timing phase and a logically open and close of the valve. The size and shape of cams on camshaft are the main factors which affecting valve working and timing efficiency. For an engine, camshaft is concerned about its charging accessories, exported power, motive ability and wasting, furthermore, the profile error of the cam is one important reason of noising. Camshaft was related tightly to the motivity and convenience of the car.Quality assuring comes from both excellent processing and after-manufacture checking. As the development of modern industry, traditional touched measuring and 2D measuring can't follow the modern production requirement. In this paper non-touched 3D measuring based on computer vision is used in measuring of camshaft, and some key points that refer to camshaft 3D measuring are deeply explored.But concerned with camshaft's machining precision, recent CCD 3-dimensional measuring can't meet the request. So in this paper, two useful methods for improving the measuring precision based on certain theory are put forward.First, put forward a feature matching method based on nonregular model which using the theory of angle picking and angle matching to solve the problem met in measuring process which is that coded point and self-feature method can't help easily matching or can't meet a certain precision.Second, put forward matching method for thin feature based on ball centering to solve the problem that two sides of the thin feature can't be matched successfully using normal way.In corresponding experiment, the feature matching method based on nonregular model which using the theory of angle picking and angle matching improved the normal precision to less than 0.04mm, the matching method for thin feature based on ball centering can maintain a full matching of cloud points. 3D measuring precision has been improved effectively by using above methods.Research of the exact 3D measuring method of camshaft is directly related to capability improvement of itself and the engine. To solve the difficulties in experiment base on multi-phasic and complicated curve camshaft measuring, can perfect the 3D non-touched measuring theory, improve modern measuring method. The research production can also be used to other exact parts which have complicated curves. Finally, it's not enough to improve just from measuring method, there are more work to do. For example, in hardware, measuring precision of the machine need to be improved, in software, arithmetic of shooting and matching still need to be improved.