Three-dimensional Reconstruction Of Human Hair Based On Point Cloud Data

With the rapid development of computer technology, manufacturing industries in today's information age have gone far beyond their traditional scope, which base on the traditional manufacturing technology and now integrate computer technology, control technology, sensor technology and mechanical, electrical and optical integration technology. A process of Specific parts is no longer a material and energy transfer, but is more emphasis on its treatment of information. Two different manifestations of areas will be existed in the manufacturing sector of the information society, which are namely product information model and material products, and because of the most innovative and valuable parts of product processing to be included in the product model, the acquirement of product information model should be put on an important position in the production activities by the manufacturing of the time information.According to the generation of different types of surfaces, the product information model can be divided into non-free-form information model and free-form information model. The latter is the focus of this paper. In the CAD / CAM applications, it is difficult to be directly designed by using traditional modeling methods that are based on the product features for auto body, household appliances, computer casings, sculptures, crafts and other products with free-form surface. So reverse engineering (Reverse Engineering, RE) technology emerged to become such a powerful tool for product modeling, which is based on the existing model or reference parts. Its method can be described as follows: first of all, the space coordinates of the parts'surface are obtained by manipulating the measuring equipment, and then create the CAD model through the obtained data from the product structure. Common measurement methods are divided into mechanical contact measurement and non-contact optical measurement. Among them, the speed of non-contact measurement is very quickly, such as the speed of laser line scan has reached 15000 points / sec, which measures a large amount of data points. And then it can fully express the surface components of information. So it is very suitable for the measurement of complex free-form surfaces. This large set of data points is known as point cloud. Point cloud data based on surface modeling method is a reverse of the design concept, which is called surface reconstruction.So far, with the rapid development of the measurement technology and computer technology, the research hotspots of reverse engineering has focused on the three-dimensional reconstruction technology which is setting up comprehensive measurement model for. Reverse engineering research has two main elements: firstly, the data acquisition technology on physical model of the surface; secondly, surface reconstruction technology. Data acquisition technology provides a possibility to deal with complex physical models. Surface reconstruction technique is to restore the geometry model of original surface which is based on the "point cloud", which is the most important step of reverse engineering and one of the key technologies of CAD, Pro / E, UG and other solid modeling software. Surface reconstruction that is based on the surface has been constructed reflects the mathematical model, which is different from the process of manufacturing surface that is generated in line with its requirements ,depending on mathematical model. Therefore, surface reconstruction is also known as the reverse engineering on projects. Under normal circumstances, the shape of required surface reconstruction is very complex. The job of surface reconstruction requires and calculates a large amount of data which is only on paper in the past, but a large-capacity, high-speed computer and a variety of advanced sampling equipments provide the necessary tools with carrying out the job of surface reconstruction at recent ten years, and make it possible.Combined with Zhejiang Natural Science Foundation Project "Rapid prototyping technology in the digital applications to repair of the tissues and organs ", this paper deeply studies the acquisition of scattered point cloud, pre-processing and free-form surface reconstruction technology. The presentation of the surface reconstruction method of the NURBS quadrilateral domains that based on the Calibration of node parameters, greatly improves the speed and accuracy of the product model reconstruction, reduces the difficulty of post treatment, enhances the operability of reconstruction model and then shortens the lifestyle of the reconstruction of product model.This thesis bases on the research topic, researches the principle of data structure, methods and applications of NURBS curve and surface reconstruction by the use of the relevant theory of reverse engineering and computer graphics. It use monocular three-dimentional scanner---3DSS as measuring equipment, and do the pre-treatment of acquired data. And then, the system which considers the Windows Vista as development platform of PC, considers Visual C + +6.0 as development environment, bases on MFC and conjuncts with the development of three-dimensional graphic reconstruction system of OpenGL generates NURBS surface models, in accordance with my own improving research of the NURBS curve and surface reconstruction algorithm. Compared with the reconstruction model that generates by the Geomagic Studio 9.0 software, we might determine the accuracy and maneuverability of NURBS surface model.Main elements of this paper:(1) Analysis the application of reverse engineering background, current situation and prospect, introduce the principles of the surface reconstruction and comparatively analysis the reconstruction methods.(2) Gave detailed methods and developments of three-dimensional information acquisition technology, and talk three-dimentional scanner 3DSS series in detail, including system principle and system. Experimental data of this subject can be obtained by 3DSS_STDC_Ⅱ, one of the key points of this article is the experimental operation of the basic flow and the acquisition of the hair'point cloud data.(3) Analyze the type of point cloud data, and then determine point cloud acquired by the experimental three-dimensional camera 3DSS_STDC_Ⅱas the scan line. Demonstrate the key technology of point cloud pretreatment, and then select the reasonable data. Use Geomagic Studio 9.0 software to reduce the noise, smooth and streamline, and then acquire the point cloud after the treatment results.(4) Analyze the reconstruction theory of curves and surfaces, and give a detailed introduction of the reconstruction method of triangular Bezier & NURBS curves and surfaces. Present of the surface reconstruction method of the NURBS quadrilateral domains that based on the Calibration of node parameters.(5) Implement OpenGL visualization model through VC + + programming based on the theoretical NUBSS surface reconstruction. Analysis the advantages and disadvantages of the surface reconstruction method of the NURBS quadrilateral domains that based on the Calibration of node parameters and Bezier Surface reconstruction to determine the feasibility of the surface reconstruction method of the NURBS quadrilateral domains that based on the Calibration of node parameters .In this paper, point cloud data acquisition and surface reconstruction is two key focuses, which this article expands around. After a detailed analysis of this article, we can clearly conclude that the biggest advantage of this method what we have discussed above is that the network division could be better adapt to the changes of curvature on surface properties, which has the great significance on surface stress analysis and functional testing, as well as the great convenience of follow-up processing such as CNC machining and rapid prototyping technology.