Reverse Engineering Based On Ccd Surface Measurement Method Study

Reverse engineering plays an increasingly important role in creative product design and shortening product development. At present, how to acquire a large quantity of 3D coordinate points efficiently and accurately has become a critical issue in reverse engineering. It can be predicted that in the near future, the intelligent measuring system with multi-sensors integration technology will be the most promising trend for free-form surface measurement. This dissertation has studied how to utilize CCD in surface measurement and as well, discussed how to apply the results that feature the surface of the object to instruct higher resolution sensors for further measuring.Main points of this dissertation are provided as follow.In Chapter 1, the importance of Reverse Engineering was summarized, the modern surface-measuring methods, such as contact measure method and the non-contact measure method based on vision technology, were simply introduced and the current of the 3D measuring system was summed up, at last we gave the reason that we studied the question included in this dissertation.In Chapter 2, the surface-measuring method based on the binocular stereo system was put forward to meet the practical requirement of this research, then the measuring principle was elaborated and some key techniques were brought forward as well.In Chapter 3, General ways for CCD calibration and the relative camera models were briefly introduced. Then, a simple and effective method for CCD calibration was put forward.In Chapter 4, In order to obtain the 3D coordinates of the object, we must get the "position" of the corresponding grid nodes quickly and exactly. To achieve this goal, the reasonable image processing algorithm was introduced, and the image processing techniques mainly included the image segmentation algorithm, the image erosion algorithm, the image dilation algorithm and the image thinning algorithm.In Chapter 5, the grid nodes extraction algorithm based on "two steps" and the nodes corresponding algorithm based on the relative positions of the grid nodes were introduced.In Chapter 6, after the analysis of the conventional measure ways with contact probes and laser probes, a fast measure method with the rectangle-division technique was brought out under the direction of the "visual information". The validity of this method has been testified through simulation experimentations.In Chapter 7, some experiments about the measuring method were studied and the factors for its error were analyzed. Then a few ways to improve the measure precision were put forward.In Chapter 8, the conclusion is made and the prospect of the future improvement is also given.