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The variable illumination 3D capture system uses kinds of cameras and lighting equipment to acquire the object information in different angles, which greatly enhances the reality of the 3D model under the arbitrary illumination conditions. In practice, the images captured are underexposed and have a low signal-to-noise ratio if the traditional way of the variable illumination is adopted in a large-scale...
This work presents a new technique based on ray tracing to extract and analyze scattering centers from complex targets, which is called ray clustering. The input of this method is the target CAD model and the output is the dominant scattering centers. This method can separate the echoes from different components by clustering rays owning the different paths and establish relationship between target...
This paper presents a forward approach to establish parametric scattering center models for known complex radar targets. In this approach, an automatic technique based on ray tracing and clustering is first developed to extract scattering centers directly from the computer-aided design (CAD) model of the targets. Following this, a set of forward methods is developed to determine the physically relevant...
In the teaching of computer maintenance, using the traditional teaching tools is difficult to teach demonstration of computer assembly, and experimental assembly supplies loss is very serious. Therefore, the author did some research of the Web in 3D virtual environment virtual interactive operation technology. Built a PC virtual assembly system on VRML/X3D, 3DS MAX and ASP. More users can remotely...
OpenGL is a commonly used modeling tool in the virtual scene modeling. However, OpenGL graphics library does not provide advanced modeling commands, in this case, it is difficult to create complicated scene models and the models which it created are less realistic. The professional three-dimensional modeling software has strong modeling capabilities, modeling vivid, but it can not meet the interoperability...
In order to accurately construct the modeling of a telerobot in a virtual environment and reduce the work of developing the graphic design, this paper took the XK-II telerobot as a prototype, using SolidWorks modeling and interactive graphics programming with Open Inventor. First of all, we constructed each entities' geometric model in SolidWorks, and then, derived these models into VRML files and...
An improved realistic mass-spring model, which is mainly based on the 3D finite strain nonlinear anisotropic elasticity theory, is presented for virtual reality based surgery simulation. Compared with the conversional mass-spring model, the proposed model is able to describe typical behaviors of living tissues such as incompressibility, nonlinearity and anisotropy. The nonlinear viscoelasticity is...
Tunnel is core of mine projects, and 3D tunnel is the important element of 3D geological models for digital mine. According to symmetry of two-dimensional tunnel along the centerline of the tunnel and symmetry of three-dimensional tunnel profiles along centerline, the paper introduced a method of new 3D tunnel modeling: symmetrical modeling, which can be used to realize the modeling of tunnels' intersection...
Three-dimensional geological modeling (3DGM) is a complicated project in the research of the three-dimensional geographic information system, and there have many data model for the geological modeling by now. The thesis introduces a kind of object-oriented data model: the Component-based Topological Data Model (CTDM). Based on the modeling principles analysis, the author discusses and gives out the...
Nowadays one of the most active areas of research in computer graphics is focused on improving the performance of radiosity methods for terascale visualization applications. The main problem for simulating large scenes based on radiosity algorithm is a highly time-consuming process. In this paper we present a task mapping model for achieving a good load balance on a distributed memory system. And...
The three dimensional geo-science modeling (3DGM) is one of the core techniques in the implementation of digital mine (DM). The paper analysis the research status about the 3DGM in DM from two aspects: the data model and the software development. Combined with the research situation, the author discusses and simulates the 3D complicated geological interface modeling, the 3D complicated geological...
Collaborative design and simulation is the key technique for complex product development, which is a highly complicated multidisciplinary process. The information sharing and model transferring among different disciplinary domains are the bottleneck of complex product collaborative design and simulation. To solve this problem, this paper proposes the complex product collaborative design and simulation...
The data of welding seam width and height were obtained by TIG welding experiments. Two models were established using BP neural networks: One can predict the weld seam dimensions by inputting the welding parameters, and the other model can perform oppositely. Originally by inputting given welding seam dimensions to the model one, the welding parameters can be predicted. Then change the parameters...
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