3D visualization of tomographic volume data using the generalized voxel model

Multi-slice images obtained from computer tomography and magnetic resonance imaging represent a 3D image volume. For its visualization we use a raycasting algorithm working on a gray-scale voxel data model. This model is extended by additional attributes such as membership to an organ or a second imaging modality (generalized voxel model). It is shown that the combination of different surface-rendering algorithms together with cutting and transparent display allow a realistic visualization of the human anatomy.The investigations were supported in part by the Deutsche Forschungsgemeinschaft and the Werner Otto Foundation, Hamburg.     

A taxonomy of 3D occlusion management for visualization

While an important factor in depth perception, the occlusion effect in 3D environments also has a detrimental impact on tasks involving discovery, access, and spatial relation of objects in a 3D visualization. A number of interactive techniques have been developed in recent years to directly or indirectly deal with this problem using a wide range of different approaches. In this paper, we build on previous work on mapping out the problem space of 3D occlusion by defining a taxonomy of the design space of occlusion management techniques in an effort to formalize a common terminology and theoretical framework for this class of interactions. We classify a total of 50 different techniques for occlusion management using our taxonomy and then go on to analyze the results, deriving a set of five orthogonal design patterns for effective reduction of 3D occlusion. We also discuss the "gaps" in the design space, areas of the taxonomy not yet populated with existing techniques, and use these to suggest future research directions into occlusion management.     

A new lossless orthogonal simplification method for 3D objects based on bounding structures

This paper presents a new approach to simplify 3D binary images and general orthogonal pseudo-polyhedra (OPP). The method is incremental and produces a level-of-detail sequence of OPP, where any object of this sequence bounds the previous objects and, therefore, is a bounding orthogonal approximation of them. The sequence finishes with the axis-aligned bounding box. OPP are encoded using the Extreme Vertices Model, a complete model that stores a subset of their vertices and performs fast Boolean operations. Simplification is achieved by using a new strategy, which relies on the application of 2D Boolean operations. We also present a technique, based on model continuity, for better shape preservation. Finally, we present a data structure to encode in a progressive and lossless way the generated sequence. Tests with several datasets show that the proposed method produces smaller storage sizes and good quality approximations compared with other methods that also produce bounding objects.     

An efficient method for fully automatic 3D digitization of unknown objects

Our goal is to develop a complete and automatic scanning strategy with minimum prior information about the object shape. We aim to establish a methodology for the automation of the 3D digitization process. The paper presents a novel approach to determine the Next Best View (NBV) for an efficient reconstruction of highly accurate 3D models. Our method is based on the classification of the acquired surfaces into Well Visible and Barely Visible combined with a best view selection algorithm based on mean shift, which avoids unreachable positions. Our approach is applicable to all kinds of range sensors. To prove the efficiency and the robustness of our method, test objects are first scanned manually by experts in 3D digitization from the VECTEO company. The comparison of results between manual and automatic scanning shows that our method is very efficient and faster than trained experts. The 3D models of the different objects are obtained with a strongly reduced number of acquisitions while moving efficiently the ranging device. The obtained results prove the effectiveness and the versatility of our 3D reconstruction approach for industrial applications.     

A 3D visualization system for hurricane storm-surge flooding

Three-dimensional computer visualization and animation can provide a substitute for coastal residents', lack of personal experience with hurricane-surge flooding. Tremendous progress has been made in 3D animation in the last decade, which movies such as Perfect Storm and The Day After Tomorrow have demonstrated. However, the 3D visualization and animation system for storm-surge flooding differs from those in Hollywood movies in three aspects. First, objects such as buildings, roads, and trees in a synthetic 3D visualization environment not only have to be able to duplicate the real-world feature visually, but also be georeferenced so users can find real locations through addresses or spatial coordinates. The sizes and shapes of buildings and trees have to be accurate so users can sense the severity of flooding by comparing the water level with heights of familiar objects. Second, the magnitude, extent, and process of storm-surge flooding have to be accurate enough to represent the real situation. This information has to be based on hydrodynamics of storm surge. Third, the damage extent of a property caused by storm surge and waves, such as the collapse of a house, must be determined by engineering rules. Recent advances in high-resolution remote-sensing technology and numerical modeling make it possible to provide accurate data for the earth's surface features and storm-surge flooding.     

Watermarking 3D objects for verification

We introduce and investigate the fundamental similarities and differences of watermarking 3D graphic models compared to 2D images, and propose some solutions to address a class of applications of digital watermarking-the verification of 3D polygonal models. To our knowledge, watermarking of 3D objects for verification purposes has not been addressed in any published literature. The proposed scheme, in its present form, is not intended for use in applications that require robust watermarks. One recent work in 3D data hiding addressed applications requiring robust means of hiding data. We first introduce digital watermarking, discuss its goals and application domains, and explain the different categories of watermarks. We believe the goals and applications will remain fairly similar for 2D images and 3D models     

A particle system for interactive visualization of 3D flows

We present a particle system for interactive visualization of steady 3D flow fields on uniform grids. For the amount of particles we target, particle integration needs to be accelerated and the transfer of these sets for rendering must be avoided. To fulfill these requirements, we exploit features of recent graphics accelerators to advect particles in the graphics processing unit (GPU), saving particle positions in graphics memory, and then sending these positions through the GPU again to obtain images in the frame buffer. This approach allows for interactive streaming and rendering of millions of particles and it enables virtual exploration of high resolution fields in a way similar to real-world experiments. The ability to display the dynamics of large particle sets using visualization options like shaded points or oriented texture splats provides an effective means for visual flow analysis that is far beyond existing solutions. For each particle, flow quantities like vorticity magnitude and A2 are computed and displayed. Built upon a previously published GPU implementation of a sorting network, visibility sorting of transparent particles is implemented. To provide additional visual cues, the GPU constructs and displays visualization geometry like particle lines and stream ribbons.     

Web-based visualization of spatial objects in 3DGIS

Adaptive rendering large and complex spatial data has become an important research issue in a 3DGIS application. In order to transmit the data to the client efficiently,this paper proposes a node-layer data model to manage the 3D scene. Because the large spatial data and limited network bandwidth are the main bottlenecks of web-based 3DGIS,a client/server architecture including progressive transmission methods and multiresolution representations,together with the spatial index,are developed to improve the p...     

A 3-D visualization method for image-guided brain surgery

This paper deals with a 3D methodology for brain tumor image-guided surgery. The methodology is based on development of a visualization process that mimics the human surgeon behavior and decision-making. In particular, it originally constructs a 3D representation of a tumor by using the segmented version of the 2D MRI images. Then it develops an optimal path for the tumor extraction based on minimizing the surgical effort and penetration area. A cost function, incorporated in this process, minimizes the damage surrounding healthy tissues taking into consideration the constraints of a new snake-like surgical tool proposed here. The tumor extraction method presented in this paper is compared with the ordinary method used on brain surgery, which is based on a straight-line based surgical tool. Illustrative examples based on real simulations present the advantages of the 3D methodology proposed here.     

3D mapping with multi-resolution occupied voxel lists

Most current navigation algorithms in mobile robotics produce 2D maps from data provided by 2D sensors. In large part this is due to the availability of suitable 3D sensors and difficulties of managing the large amount of data supplied by 3D sensors. This paper presents a novel, multi-resolution algorithm that aligns 3D range data stored in occupied voxel lists so as to facilitate the construction of 3D maps. Multi-resolution occupied voxel lists (MROL) are voxel based data structures that efficiently represent 3D scan and map information. The process described in this research can align a sequence of scans to produce maps and localise a range sensor within a prior global map. An office environment (200 square metres) is mapped in 3D at 0.02 m resolution, resulting in a 200,000 voxel occupied voxel list. Global localisation within this map, with no prior pose estimate, is completed in 5 seconds on a 2 GHz processor. The MROL based sequential scan matching is compared to a standard iterative closest point (ICP) implementation with an error in the initial pose estimate of plus or minus 1 m and 90 degrees. MROL correctly scan matches 94% of scans to within 0.1 m as opposed to ICP with 30% within 0.1 m.     

基于三维可视化的计算机辅助痛风诊断方法

为方便骨科医生更为准确地对痛风性关节炎进行诊断,提出一种基于三维可视化的计算机辅助痛风诊断方法,实现区域分割、三维重建及指标评估分析三大功能。以双能量CT序列为输入,利用阈值分割、区域增长及逻辑回归等算法对骨质和尿酸盐结晶(monosodium urate,MSU)区域进行分割,以统计相应指标和对分割后区域进行三维重建的方式进行辅助诊断。实验结果表明,该方法能够精确地统计痛风诊断相应指标,并可在二维和三维空间显示定位相应的骨质及尿酸盐结晶区域,有效辅助医生进行诊断。     

Interactive visualization of 3D seismic data: a volumetric method

The authors demonstrate the utility of examining seismic data with a volumetric scheme, whereby a synoptic view of the interior of the data volume is possible before conventional interpretation. High-amplitude seismic events, representing reflections from subterranean surfaces, are transformed to color pixels, and the resulting 3-D images reveal the structure of the geological layers. Such morphological features as hills, valleys, and faults are apparent indicating that the approach could prove useful for identifying potential oil reservoirs. The authors implement the technique on a personal computer to produce displays of similar quality, but they find that the construction of the 3-D images is too slow for reasonable interactivity. However, with the addition of a parallel-processing accelerator, a personal-computer-based workstation would be feasible for this kind of 3-D visualization and interpretation     

A new monocular vision measurement method to estimate 3D positions of objects on floor

A new visual measurement method is proposed to estimate three-dimensional (3D) position of the object on the floor based on a single camera. The camera fixed on a robot is in an inclined position with respect to the floor. A measurement model with the camera’s extrinsic parameters such as the height and pitch angle is described. Single image of a chessboard pattern placed on the floor is enough to calibrate the camera’s extrinsic parameters after the camera’s intrinsic parameters are calibrated. Then the position of object on the floor can be computed with the measurement model. Furthermore, the height of object can be calculated with the paired-points in the vertical line sharing the same position on the floor. Compared to the conventional method used to estimate the positions on the plane, this method can obtain the 3D positions. The indoor experiment testifies the accuracy and validity of the proposed method.     

异种油藏网格模型三维可视化优化方法研究

在油藏三维建模和数值模拟软件中,网格模型在存储格式、网格排序等方面存在较大差异,且大规模网格模型将占用大量存储空间同时需要运算大量数据,限制其绘制速度。为此,提出了异种油藏网格模型三维可视化优化方法,加载异种油藏网格模型,并实现网格模型消隐算法,提高油藏网格模型的绘制速度。实验结果表明,该方法能够加载异种油藏网格模型,与优化前的网格模型相比,优化后的模型在存储、绘制速度和效果上有着明显的优势。     

再现3D对象

多亏有了Google上的一种免费工具,3D建模变得不再是一个痛苦而笨拙的过程。Jerome Turner介绍SketchUp的主要功能。     

Clustering-based force-directed algorithms for 3D graph visualization

The Journal of Supercomputing - Force-directed algorithm is one of the most commonly used methods for visualization of 2D graphs. These algorithms can be applied to a plethora of applications such...