Study On Using The Vision Measuring Technology In 3D Measuring For The Rough Precious Stone

structured-light method is to transform the light beam that the laser instrument is sent out into different geometry shape light through the optical system, including point, mongline, multithreading,single round , concentric more round,gridding cross etc. casts to scenery, forms the pattern and ingested by the camera on the scenery (this method is called initiative sensing method), and then calculates , gets the depth picture of the scenery surface according to the triangular method and sensing structure parameter by the picture , furthermore it can calculate out three-dimensional coordinate value. The value of each point in the depth picture shows the absolute distance of every point to the camera on the scenery surface, so it can directly get the form and position message of the target from that. This kind of method has two main advantages. First: It has formed a light mode, which has already been known in the work space, the light mode's changing indicates that the object is changing. It can also reduce the calculating complication,improve three-dimension range measurement precision. Furthermore, the sensor based on this method has the advantages of small, light, low price, easy installed used and maintained, this makes it become the most frequently used technology at the three-dimension apperception in industry. But the method has the problem of sheltering, precision and speed contradict each other and they are difficult to raise meanwhile. structured-light method can be divided into single method , mongline method and pattern method according to the kind of project light pattern. Namely they are point, one-dimensional line and two-dimensional pattern. Thereupon the time of the scanning can be shortened, but the corresponding degree of difficulty of confirming corresponding relation will increase. At present people commonly analyze and measure the 3D shape of precious stones by hand in the course of its machining process. The process of measurement is complex and difficult. What's more, it's hard to grasp the characteristics of the main body in the process of designing the product's figure based on the application requirement. The material will be wasted easily and the efficiency is low. In order to solve these problems, this text deploys research to find a 3D measurement system of precious stones. It also designs a measurement system of precious stones'3D shape based on structured light. The content of this text is as follows: Chapter 1:Prodrome. It introduces the investigation status of the machine vision in the country and abroad and its application instance in some fields. It also illustrates the purpose and meaning of this text. Chapter 2:The structured light 3D measurement theory. This chapter mainly discusses the imaging model of the vidicon, the demarcating of the vidicon and the 3D measurement model based on the linear structured light. At first we introduce the imaging model of the object. Then we expound the method of the linear model demarcating which can ascertain the correspondence between the reference frame of the object and the reference frame of the picture. Then we introduce the theory of the structured-light inspection and measurement. At last we found the 3D measurement model based on the linear structured light and give the formulas of founding the model. Chapter 3:pretreatment of structured light image. Original pictures obtained from the vidicon are 2D ones. They have no depth information. In order to obtain the 3D depth information from these pictures, we distill the useful 2D information from the original picture to get the 3D depth. So we deal the picture with the two-value treatment at first. This paper compare with the two ways getting threshold and use the p-tile method to distill the threshold according to the requirement of the system at last. The worked picture may have the yawp or the unclear brim, so we deal the picture with filtrating the wave by some methods. After comparing with these methods, we choose the keeping brim filter. Then we distill the skeleton of the figure being irradiated by scanning every pels one by one. Chapter 4:system design of 3D measurement. This chapter designs a system to measure the 3D coordinate value of precious stones based on the 3D measurement math model which is established on Chapter Two and is based on the structured light. This system includes software system and hardware system. The software design of the system which is based on the software requirement analysis and the blocking structure requirement includes 5 big blocks of the system. The 5 big blocks are: the block of obtaining, the original pictures, the block of electrical engine controlment, the block of image manipulation, the block of picking up the 3D coordinate and the block of 3D repeated formation. It empolders a simple and convenient software interface based on the function of the blocks. It also provides the main program sound code. The hardware design of the system includes a box which can satisfy the measurement precision with good real time and simple operation. This...