共查询到19条相似文献,搜索用时 93 毫秒
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基于图像的实时漫游 总被引:3,自引:0,他引:3
提出了一个点和多边形模型混合的场景表达方式,从而实现了对复杂场景的视点不受限制的实时漫游.它从多幅带深度的参考图像出发,在预处理阶段区别对待场景中平面物体和曲面物体在参考图像中的对应像素.对于在参考图像所占区域较大的空间平面,用传统的多边形模型方式对其进行表达,试图恢复出其平面方程,然后通过采样密度比较和重采样过程,将该空间平面在所有参考图像中的出现合并成一个均匀采样的纹理图像;而对于空间曲面或在参考图像中所占面积较小的平面,使用点的形式对其进行表达,通过采样密度的比较去掉冗余的点,将保留下来的点按其空间位置进行聚类.同时,对于场景中那些不被所有参考图像所拍摄到而在漫游过程中可能形成空洞的部分,提出一个空洞预填补技术,在预处理阶段即对这类空洞进行填补,从而大大减少了漫游阶段出现空洞的几率.在漫游阶段则使用纹理映射和点Warping的方式进行绘制,以充分利用图形硬件的加速功能. 相似文献
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基于图像的建模和绘制技术综述 总被引:2,自引:0,他引:2
对基于图像的建模和绘制(IBMR)技术进行综述性介绍,着重阐述IBMR研究的最新进展.文中扼要地回顾了一些基本的IBMR方法,并对这些方法的优点和局限性进行分析比较.最后我们简单介绍IBMR的一些最新研究趋势和可能的应用前景. 相似文献
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虚拟环境中森林植被的实时可视化技术研究 总被引:3,自引:0,他引:3
森林植被的实时可视化技术是复杂虚拟环境渲染的重要组成部分,也是影响虚拟环境逼真度的重要因素。森林植被绘制的实时性是制约VR应用的重要方面。论文综述了虚拟环境中植被可视化的研究成果,对所有的技术方法的优、缺点和应用范围进行了分类比较。最后,展望了植被可视化技术的发展趋势。 相似文献
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虚拟场景建模关键技术研究 总被引:2,自引:0,他引:2
虚拟场景建模技术是虚拟现实技术的基础和核心。目前虚拟场景建模技术主要有三种类型:基于三维几何图形绘制技术、基于图像的绘制技术和基于几何图形混合图像加速的绘制技术。基于图像的绘制技术是计算机图形学的一个研究热点。 相似文献
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一种新的三维地景库的建模方法 总被引:1,自引:0,他引:1
针对传统的模拟器计算机成像系统之不足,提出了1种新的视景系统的建模方法,即基于矢量数字地图的三维地景生成算法。该算法以矢量地图为约束,各种地表纹理作为输入样图,用矢量地图中的高程信息构建三维地形网格,并根据矢量数字地图中图元之间的不同属性映射相应的纹理,得到了与矢量数字地图相一致的三维地景。与传统的地景库生成算法相比,新算法生成的三维地景更加真实精确;解决了以往地景库一经生成就无法更改的问题;具有一定的预测和重现场景的功能;缩短了地景库的开发周期,降低了开发成本。同时,运用了基于视点的地景数据动态调度策略,可实现真实场景的实时绘制。 相似文献
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运用层次纹理映射的基于图像绘制算法 总被引:4,自引:0,他引:4
提出一种基于图像绘制(image-basedrendering,简称IBR)的算法,以发挥图形卡的纹理映射功能,并能表现物体表面的三维凹凸细节.首先将深度图像的像素按其相关深度分为多层纹理图像,然后利用纹理映射的硬件支持,将这些层次纹理图像依次投影到与视点相关的成像面上,以得到所需目标图像.为了避免目标图像上出现空洞,在生成时,将纹素在深度层次上进行扩展.由于层次纹理图像需要较大的存储空间,并且在装入纹理缓冲时要花费大量时间,为此还提出一种基于压缩层次纹理图像的目标图像生成算法.实验表明新算法是有效的,尤其适于处理与整个物体大小相比深度层次不太多的三维景物,如有表面凹凸纹理(浮雕、门窗等)的建筑物表面等. 相似文献
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基于图像的虚拟场景实时漫游 总被引:2,自引:0,他引:2
提出一种基于图像的并行绘制算法 ,通过分割图像显示窗口并行绘制 ,实现了三维场景的高分辨率图像的实时绘制 该算法按各节点计算性能分配任务 ,实现了负载平衡 利用三维场景漫游时相邻帧之间的相关性 ,采用RLE(RunLengthEncoded)压缩方法传输图像 ,降低了传输开销 实验结果表明 ,在 4台PC组成的机群上 ,实现了5 12× 5 12大小的图像的实时绘制 相似文献
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李亚峰 《计算机工程与应用》2009,45(14):176-178
由于日光模型的复杂性,逼真地绘制日光照射下户外场景的真实感图像是一个困难的问题。目前的绘制方法或者因为采用的模型过于简单而真实感程度差,或者绘制过程过于复杂耗时而影响其应用。应用图像相似度理论,提出了一种综合使用基于几何和基于图像的混合绘制方法。绘制过程分为两步,首先,使用简单的光照模型近似绘制场景,然后,采用基于图像的绘制和处理方法补充第一步无法表现的效果。由于采用了基于图像相似度理论的方法,能够克服基于图像绘制技术需要处理巨大数据量的缺点。用这种两步法绘制自然光照下的户外景物,只需要简单的光照模型和物体材质属性以及很少的数据存储量。该方法在真实感程度、绘制速度和数据存储量三者间取得了比较好的平衡,绘制建筑物的实验证明了方法的有效性。 相似文献
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This paper presents a hybrid (geometry- and image-based) framework suitable for providing photorealistic walkthroughs of large,
complex outdoor scenes, based only on a small set of real images from the scene. To this end, a novel data representation
of a 3D scene is proposed, which is called morphable 3D panoramas. Motion is assumed to be taking place along a predefined path of the 3D environment and the input to the system is a sparse
set of stereoscopic views at certain positions (key positions) along that path (one view per position). An approximate local
3D model is constructed from each view, capable of capturing the photometric and geometric properties of the scene only locally.
Then, during the rendering process, a continuous morphing (both photometric as well as geometric) takes place between successive
local 3D models, using what we call a ‘morphable 3D model’. For the estimation of the photometric morphing, a robust algorithm
capable of extracting a dense field of 2D correspondences between wide-baseline images is used, whereas, for the geometric
morphing, a novel method of computing 3D correspondences between local models is proposed. In this way, a physically valid
morphing is always produced, which is thus kept transparent from the user. Moreover, a highly optimized rendering path is
used during morphing. Thanks to the use of appropriate pixel and vertex shaders, this rendering path can be run fully in 3D
graphics hardware and thus allows for high frame rates.
Our system can be extended to handle multiple stereoscopic views (and therefore multiple local models) per key position of
the path (related by a camera rotation). In this case, one local 3D panorama (per key position) is constructed, comprising
all local 3D models therein, and so a ‘morphable 3D panorama’ is now used during the rendering process. For handling the geometric
consistency of each 3D panorama, a technique which is based on solving a partial differential equation is adopted. The effectiveness
of our framework is demonstrated by using it for the 3D visual reconstruction of the Samaria Gorge in Crete. 相似文献
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Norishige Chiba Kazunobu Muraoka Akio Doi Junya Hosokawa 《Computer Animation and Virtual Worlds》1997,8(4):191-199
Visual simulation of forest scenery is a challenging problem which includes the following tough sub-problems: generation of vegetation, representation of trees, simulation of colour change of leaves, and rendering of numerous trees. Among those sub-problems, this paper treats mainly the last one. A conventional polygon-based rendering algorithm often produces troublesome aliasing effects when it is applied to the objects having complex fine surfaces, such as forest scenery. In this paper, we show that an extended volume rendering technique applied to 3D textures, i.e. volume data in this paper, of trees is effective in the concerned problem. Kajiya left, as further work, the problem of rendering forest scenery by applying his 3D texture called texel. Our rendering method consists of the following three steps: we first generate 3D textures of trees from their polygon-based geometric models, we next arrange the 3D textures, allowing their possible mutual intersections, on the surface of a given polygon-based terrain model according to a simulated vegetation, and we finally produce an image of forest scenery by applying the ray-tracing algorithm including our slightly extended volume rendering technique. © 1997 John Wiley & Sons, Ltd. 相似文献
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随着图形硬件性能的提升,大规模地形绘制的主要瓶颈已从绘制能力不足转变为大数据的传输,针对这一问题提出一种支持大规模地形的瓦片调度与实时绘制算法。将超大地形数据以瓦片金字塔形式存储于硬盘,绘制每一帧时只调度当前场景所需的少量瓦片进入显存。首先利用GPU实时计算地形网格点的地理坐标并传回CPU分析可见范围,然后采取瓦片四叉剖分、规则化处理和瓦片合并等一系列操作在所有LOD层中拣选最优瓦片集合并调入内存,在内存中利用一块固定大小的缓存进行管理与更新,并最终以单张纹理的形式传入显存进行采样和绘制。实验表明,该算法节约了大量的显存带宽,有效提升了系统在数据传输方面的执行效率,在大规模地形调度与绘制中取得了较好的效果。 相似文献
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This paper presents an efficient inverse warping algorithm for generating novel views from multiple reference images taken from different viewpoints. The method proceeds in three steps: preprocess for edge-pixel extraction, inverse warping from the primary image, and hole filling from remaining reference images. In using advantages of epipolar-line features and the depth discontinuity in the reference images, the inverse warping can be efficiently applied in segments, accelerating the rendering process substantially. Two acceleration techniques are proposed at the last stage for hole filling. By using the algorithm proposed, we may navigate a virtual environment at an interactive rate. 相似文献