Design Of 3-D Rotary Measurement System Based On Light-Sectioning Method

With the rapid development of society and economy, the three-dimensional shape measurement method for continuously updated. In three-dimensional optical measurement methods, the light sectioning method has been widely research and development, because of it have many advantages like non-contact, high accuracy, good real-time performance, etc.The light sectioning method using linear laser scanning the surface of the object, by gathering photos which containing the depth change information of the object’s surface, finally, we can carry out the three-dimensional reconstruction. Choosing rotating scanning in the measuring system, and putting the object in the rotating platform, by stepping motor drives the rotating 360 degree scanning. We can let the platform and CCD work at the same time through programming, get different images with the different collection speed, each acquired image can be extracted under the corresponding rotation Angle of the surface of the object under test profile, all the contour through software pieced together, can get the three-dimensional shape about the surface of the object.In the thesis, we introduced the principles and methods of several commonly used to detect the three-dimensional shape in the first chapter. According to the different advantages and disadvantages of structured light method to make a contrast, research the present situation of structure light, put forward by The light sectioning method in this thesis. To study in-depth of The light sectioning method in the second chapter. Analysis of different optical path and applicability about this method. To study the technology of extracting light strip’s center which is the key technology of this measuring instrument, it can provide ideas for us in actual operation later. In the third chapter, introduced the design and assembly of the entire three-dimensional measurement system. And this system is divided into hardware and software, in this chapter, we can get more information about it. In the fourth chapter, introduced that how to extract light strip’s center. It contains the section of image preprocessing, the light strip’s center extracting, and using different methods to deal with the image to do the results comparison. In the fifth chapter, introduced the coordinate transformation from two-dimensional to three-dimensional. And showing the last 3-D reconstruction result. In the last chapter, we summarized the main work of this topic and the shortage of this method, as well as the innovation and the prospect of this subject.In this thesis, the system is based on the light sectioning method, Through this process, the main work of this paper is as follows:1.To study in-depth of The light sectioning method measurement system and implementation steps. To form a complete measurement system which included the image acquisition, the data processing, and 3-D reconstruction.2. To study the technology of extracting light strip’s center, according to the actual circumstance of the image, put forward the feasible method, and achieved a good effect of extraction which attained to the sub-pixel precision level.3. CCD camera in coordination with rotating platform operation by the team of the software programming. And it can be chose the collection precision.