Structured grids and some of their applications in natural sciences are discussed. The problem of their visualization and quantitative evaluation is considered and possible ways for its solution sketched. Resampling a...
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ISBN:
(纸本)0769522238
Structured grids and some of their applications in natural sciences are discussed. The problem of their visualization and quantitative evaluation is considered and possible ways for its solution sketched. Resampling a structured grid onto a regular one is such a possible solution offering the additional benefit of enabling quantitative evaluations, too. This resampling is achieved by a preliminary tetrahedronization of the structured grid(s) and a subsequent digitalization of the constituent tetrahedrons using an adaptation of the 3d-Bresenham algorithm. Advantages anddisadvantages of this approach as compared to other possible schemes are discussed. An implementation based on our open source f3d-file format for storage andtransmission of volumetric data is presented, and results from applying it to real-worlddata shown.
The problem of virtual view creation has received increasing attention in recent years. Major current approaches are based on modified stereo vision systems. Recently the structure light measurement system based on di...
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ISBN:
(纸本)0769522238
The problem of virtual view creation has received increasing attention in recent years. Major current approaches are based on modified stereo vision systems. Recently the structure light measurement system based on digital light projection supported by special data coding andprocessing allow to rapid3d shape acquisition. Application of this technology to record3ddata has increased significantly the accuracy of reconstructed shape and simplifieddata manipulation process. In the paper the general concept of virtual reality system supported by data gathered by means of structure light projection is presented. The methodology of conversion of cloud of measurement points (x,y,z,R,G,B) into virtual reality environment is described. It is supported by implementation of a virtual camera concept, as the mean for interactive object visualization. The methodology of real time 3d object visualization based on its coding by means of specially formed contours and their B-spline approximation is presented. The applicability of the methodology has been shown on numerically generateddata which simulate performance of the measurement system. The total processing path was successfully tested.
We propose a depth scaling method that enables visualization of arbitrary-shaped3d scenes on 3ddisplays. Most current 3ddisplays have a depth limitation, while the scene to be displayed has not. The trivial solutio...
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ISBN:
(纸本)0769522238
We propose a depth scaling method that enables visualization of arbitrary-shaped3d scenes on 3ddisplays. Most current 3ddisplays have a depth limitation, while the scene to be displayed has not. The trivial solutions as clipping or linear scaling of the scene's 3d bounding box suffer from non-optimal utilization of the display's capabilities. Our approach uses spatially adaptive depth scaling that maximizes the perceptual 3d effect. From the original scene geometry, the topology and local depth ordering among objects are preserved, while depth linearity is disregarded. The scaling method applies to nearly all 3ddisplays, such as glasses-based, head-tracked, multi-view, holographic and volumetric 3ddisplays. Subjective tests with the dynamic dimension display system show that our method significantly increases the perceptual 3d effect.
3d objects are an important type of multimedia data with many promising application possibilities. defining the aspects that constitute the similarity among 3d objects, anddesigning algorithms that implement such sim...
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ISBN:
(纸本)0769522238
3d objects are an important type of multimedia data with many promising application possibilities. defining the aspects that constitute the similarity among 3d objects, anddesigning algorithms that implement such similarity definitions is a difficult problem. Over the last few years, a strong interest in methods for feature-based3d similarity search has arisen, and a growing number of competing algorithms for content-based retrieval of 3d objects have been proposed. We present an extensive experimental evaluation of the retrieval effectiveness and efficiency of a large part of the current state-of-the-art feature-based methods for 3d similarity search, giving a contrasting assessment of the different approaches.
A 3d information space is a three-dimensional visualization that contains 2dvisualizations and puts them in a semantic context. In this poster, we sketch how Mixed Reality (MR) can be exploited as a technology in ord...
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ISBN:
(纸本)0769521916
A 3d information space is a three-dimensional visualization that contains 2dvisualizations and puts them in a semantic context. In this poster, we sketch how Mixed Reality (MR) can be exploited as a technology in order to realize better interaction in a 3d information space and, as a result, to develop new interactive visualization techniques. Here, the real space is used as a metaphor for interacting with the 3d information space.
In this paper a novel method for 3d model content-based search and retrieval based on the 3d Radon Transform and a querying-by-3d-model approach, is presented. descriptors are extracted using the 3d Radon Transform an...
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ISBN:
(纸本)0769522238
In this paper a novel method for 3d model content-based search and retrieval based on the 3d Radon Transform and a querying-by-3d-model approach, is presented. descriptors are extracted using the 3d Radon Transform and applying a set of functionals on the transform coefficients. Similarity measures are then created for the extracteddescriptors and introduced into a 3d model-matching algorithm. This results to a very fast and accurate matching method. Experiments were performed using two different databases and comparing the proposed method with others. Experimental results show that the proposed method can be used for 3d model search and retrieval in a highly efficient manner.
In this paper a real-time, handheld3d model acquisition system consisting of a laser projector a video camera and a turntable is described. The user projects a stripe of light at the 3d object by hand while rotating ...
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ISBN:
(纸本)0769522238
In this paper a real-time, handheld3d model acquisition system consisting of a laser projector a video camera and a turntable is described. The user projects a stripe of light at the 3d object by hand while rotating the object on a turntable. The projected light and LEd markers attached to the laser projector and turntable are captured by the video camera. By estimating the 3d orientation of the laser projector and the turntable angle from the 2d locations of the markers, the 3d location of the surface lit by the laser can be calculated. In addition, post-processing algorithms for refining the estimated3ddata have been proposed. The algorithm not only improves the accuracy of the 3d measurement, but also achieves to decrease the number of LEds for 3ddata estimation;therefore, it significantly improves the user's convenience in scanning the object. With this system, users can measure an entire 3d object in real-time.
In this paper we describe a system that can build3d animal models and synthesize animations in 3d virtual environments. The model is constructed by 2d images captured by specific views. The animation is synthesised b...
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ISBN:
(纸本)0769522238
In this paper we describe a system that can build3d animal models and synthesize animations in 3d virtual environments. The model is constructed by 2d images captured by specific views. The animation is synthesised by using physical motion models of the animal and tracking data from image sequences. Finally, the user selects some points of the 3d world and a smooth and safe motion path, which passes by these points, is created. The main assumption of the 3d modelling is that the animal could be divided into parts whose normal sections are ellipses. Joints and angles between skeleton points are used in order to decrease models complexity. Using the above methodology, a snake, a lizard and a goat are reconstructed.
This paper describes an approach to texture mapping a 3d city model obtained from aerial and ground-based laser scans with oblique aerial imagery. First, the images are automatically registered by matching 2d image li...
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ISBN:
(纸本)0769522238
This paper describes an approach to texture mapping a 3d city model obtained from aerial and ground-based laser scans with oblique aerial imagery. First, the images are automatically registered by matching 2d image lines with projections of 3d lines from the city model. Then, for each triangle in the model, the optimal image is selected by taking into account occlusion, image resolution, surface normal orientation, and coherence with neighboring triangles. Finally, the utilized texture patches from all images are combined into one texture atlas for compact representation and efficient rendering. We evaluate our approach on a data set of downtown Berkeley.
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