基于图像的快速碰撞检测算法

基于图像的碰撞检测算法是一类较新的碰撞检测方法，它有效地利用图形硬件的加速功能，以减轻CPU的负担，文中提出一种基于图像的快速碰撞检测算法，该算法在继承一般基于图像的碰撞检测算法优点的同时，不但能处理任意形状的多面体，而且具有更高效率，该算法主要采用对物体表面进行自动凸分解，将凸分解结果合理的组织成层次二叉树结构，以及绘制加速等技术，与相关算法的实验比较说明，该算法在性能上有较大的提高。     

RECODE: an image‐based collision detection algorithm

Object interactions are ubiquitous in interactive computer graphics, 3D object motion simulations, virtual reality and robotics applications. Most collision detection algorithms are based on geometrical object‐space interference tests. Some algorithms have employed an image‐space approach to the collision detection problem. In this paper we demonstrate an image‐space collision detection process that allows substantial computational savings during the image‐space interference test. This approach makes efficient use of the graphics rendering hardware for real‐time complex object interactions. Copyright © 1999 John Wiley & Sons, Ltd.     

High Performance GPU‐based Proximity Queries using Distance Fields

Proximity queries such as closest point computation and collision detection have many applications in computer graphics, including computer animation, physics‐based modelling, augmented and virtual reality. We present efficient algorithms for proximity queries between a closed rigid object and an arbitrary, possibly deformable, polygonal mesh. Using graphics hardware to densely sample the distance field of the rigid object over the arbitrary mesh, we compute minimal proximity and collision response information on the graphics processing unit (GPU) using blending and depth buffering, as well as parallel reduction techniques, thus minimizing the readback bottleneck. Although limited to image‐space resolution, our algorithm provides high and steady performance when compared with other similar algorithms. Proximity queries between arbitrary meshes with hundreds of thousands of triangles and detailed distance fields of rigid objects are computed in a few milliseconds at high‐sampling resolution, even in situations with large overlap.     

Hybrid image‐based collision detection in Java 3D

Collision detection is highly important in computer graphics and virtual reality. Most collision detection methods are object‐based, relying on testing the geometrical interference of objects, and their performance therefore depends on the geometrical complexity of the objects. Recently, image‐based methods have gained increasing acceptance for their simplicity in implementation, robustness with respect to the object geometry, and the potential to distribute the computational burden onto graphics hardware. However, all existing image‐based methods require direct calls to OpenGL, but so far there is no direct way to access OpenGL through the Java 3D API. Although Java 3D provides its own built‐in collision detection classes, they are either incorrect or inefficient. In this paper, we present a hybrid image‐based collision detection method in Java 3D, which incorporates the Java 3D built‐in collision detection and the image‐based collision detection in our specially devised scene graph. In addition, we take advantage of the fact that the 3D position of successive offscreen views (i.e. virtual views perceived by the probing object) does not change significantly and thereby reduce the occurrences of offscreen rendering, so that the collision detection becomes even faster (up to 50% in our case). Experimental results prove the correctness and efficiency of our method. Copyright © 2006 John Wiley & Sons, Ltd.     

基于流的实时碰撞检测算法

实时碰撞检测是计算机图形应用中不可或缺的问题之一,复杂物体间的实时碰撞检测至今仍未能得以很好的解决.高性能可编程图形硬件的出现,正在改变着通用计算仅能由CPU完成的传统观念.探索性地采用了可编程图形硬件来解决复杂物体间的实时碰撞检测问题.通过将两个任意物体间的碰撞检测计算映射到图形硬件以有效利用图形硬件的并行架构,由实时绘制过程快速产生碰撞检测结果.为此,算法首先将碰撞检测问题转化为一组线段集合与三角形的求交问题,以实现碰撞检测算法向可编程图形硬件的迁移.在对算法复杂度进行理性分析的基础上,给出了两种有效的优化技术以提升算法效率.实验结果表明,与现有的图像空间碰撞检测算法相比,该算法在效率、精确性和实用性方面具有明显优势.     

基于深度纹理的实时碰撞检测算法

结合层次包围盒和基于图形硬件的方法,以带深度纹理的包围盒替代物体的几何模型,利用图形硬件在纹理映射时进行深度比较,以实现碰撞检测.实验结果表明,与CULLIDE算法相比,文中算法执行效率更高且执行时间固定,具有较高的实时性.     

实时碰撞检测算法综述*

介绍了常用的基于图形的实时碰撞检测算法适用场合及实施策略,重点从构造难度、数据存储量、相交测试复杂度、紧密性、物体旋转时包围盒更新计算量、变形体碰撞适用度等方面分析了基于包围盒的碰撞检测算法,并进行了横向比较;介绍了基于图像的碰撞检测方法的特点、实施策略及研究现状。最后总结提出了算法研究中存在的问题及新的发展方向。     

Efficient collision detection using bounding volume hierarchies ofk-DOPs

Collision detection is of paramount importance for many applications in computer graphics and visualization. Typically, the input to a collision detection algorithm is a large number of geometric objects comprising an environment, together with a set of objects moving within the environment. In addition to determining accurately the contacts that occur between pairs of objects, one needs also to do so at real-time rates. Applications such as haptic force feedback can require over 1000 collision queries per second. We develop and analyze a method, based on bounding-volume hierarchies, for efficient collision detection for objects moving within highly complex environments. Our choice of bounding volume is to use a discrete orientation polytope (k-DOP), a convex polytope whose facets are determined by halfspaces whose outward normals come from a small fixed set of k orientations. We compare a variety of methods for constructing hierarchies (BV-trees) of bounding k-DOPs. Further, we propose algorithms for maintaining an effective BV-tree of k-DOPs for moving objects, as they rotate, and for performing fast collision detection using BV-trees of the moving objects and of the environment. Our algorithms have been implemented and tested. We provide experimental evidence showing that our approach yields substantially faster collision detection than previous methods     

Real-time Animation of Dressed Virtual Humans

In this paper, we describe a method for cloth animation in real‐time. The algorithm works in a hybrid manner exploiting the merits of both the physical‐based and geometric deformations. It makes use of predetermined conditions between the cloth and the body model, avoiding complex collision detection and physical deformations wherever possible. Garments are segmented into pieces that are simulated by various algorithms, depending on how they are laid on the body surface and whether they stick or flow on it. Tests show that the method is well suited to fully dressed virtual human models, achieving real‐time performance compared to ordinary cloth‐simulations.     

融合神经网络的布料碰撞检测算法

目的 针对当前在虚拟环境中布料柔体碰撞检测效率慢和准确性低的问题,提出一种根节点双层包围盒树结构和融合OpenNN （open neural networks library）神经网络加速预测碰撞检测的算法。方法 首先改进了碰撞检测常用的包围盒技术,提出根节点双层包围盒算法,减少包围盒的构造时间。其次使用神经网络优化碰撞检测技术,利用神经网络可以处理大量数据的优势,每次可以检测大量基本图元是否发生碰撞,解决了碰撞检测计算复杂性高的问题。最后准确地找到碰撞粒子并做出碰撞响应。结果 在相同的复杂布料模型情况下,根节点双层包围盒算法在运行速度上比传统混合包围盒算法快,耗时缩减了5.51%~11.32%。基于OpenNN算法的总耗时比根节点双层包围盒缩减了11.70%,比融合DNN （deep neural network）的自碰撞检测算法减少了6.62%。随着碰撞检测难度的增大,当布料模型的精度增加84%时,传统物理碰撞检测方法用时增加96%,融合DNN的自碰撞检测算法用时增加90.11%,而本文基于神经网络的算法用时仅增加了68.37%,同时表现出更高的稳定性,满足使用者对实时性的要求。结论 对于模拟场景中简单模型的碰撞,本文提出的根节点双层包围盒算法比传统的包围盒方法耗时短。对于复杂模型,基于OpenNN神经网络的碰撞检测算法在效率上优于传统的包围盒算法和融合DNN的自碰撞检查算法,而且模拟效果的准确性也得以保证,是一种高效的碰撞检测方法。     

颜色解耦光响应非均匀性噪声融合凸优化的图像伪造检测算法

当前基于光响应非均匀性噪声的伪造检测算法使用了滤色器阵列,容易产生颜色插值噪声,严重影响了其噪声的提取精度及相关性检测的分辨率;且没有考虑源相机的相关性,借助局部像素统计决策进行目标识别,削弱了算法检测精度.提出了颜色解耦光响应非均匀性(,CD-PRNU color decoupled photo response non-uniformity)噪声融合凸优化方案的图像伪造检测算法.设计颜色解耦光响应非均匀性噪声;并构造了CD-PRNU噪声残留的数学计算模型;再嵌入Bayes原理,形成贝叶斯最小风险决策,利用图像全局像素,完成伪造目标检测.同时提出凸优化方案,将真伪决策演变为凸问题,降低算法复杂度.仿真结果显示:该算法能够更有效地检测出微小尺寸伪造目标,且其误检率更低.     

基于图像空间的刚体碰撞检测的OpenGL实现

本文针对三维场景的的运动模拟,详细讨论了在OpenGL中利用摸板测试和深度测试进行碰撞检测的原理和方法.这种基于图像空间的碰撞检测方法,充分利用了图形硬件的性能并有效地降低了CPU的计算负担.由于充分结合了OpenGL的操作特点,因此本文具有一定的实践意义.     

TightCCD: Efficient and Robust Continuous Collision Detection using Tight Error Bounds

http://gamma.cs.unc.edu/BSC/ We present a realtime and reliable continuous collision detection (CCD) algorithm between triangulated models that exploits the floating point hardware capability of current CPUs and GPUs. Our formulation is based on Bernstein Sign Classification that takes advantage of the geometry properties of Bernstein basis and Bézier curves to perform Boolean collision queries. We derive tight numerical error bounds on the computations and employ those bounds to design an accurate algorithm using finite‐precision arithmetic. Compared with prior floatingpoint CCD algorithms, our approach eliminates all the false negatives and 90–95% of the false positives. We integrated our algorithm (TightCCD) with physically‐based simulation system and observe speedups in collision queries of 5–15X compared with prior reliable CCD algorithms. Furthermore, we demonstrate its benefits in terms of improving the performance or robustness of cloth simulation systems.     

Fast collision detection between complex solids using rasterizing graphics hardware

We present an efficient method for detecting collisions between complex solid objects. The method features a stable processing time and low sensitivity to the complexity of contact between objects. The algorithm handles both concave and convex objects; however, the best performance is achieved when at least one object is convex in the proximity of the collision zone (our techniques check the required convexity property as a byproduct of the calculations). The method achieves real-time performance when calculations are supported by the standard functionality of graphics hardware available on high-end workstations.     

Projection-based geometrical feature extraction for computer vision: algorithms in pipeline architectures

In this correspondence, some image transforms and features such as projections along linear patterns, convex hull approximations, Hough transform for line detection, diameter, moments, and principal components will be considered. Specifically, we present algorithms for computing these features which are suitable for implementation in image analysis pipeline architectures. In particular, random access memories and other dedicated hardware components which may be found in the implementation of classical techniques are not longer needed in our algorithms. The effectiveness of our approach is demonstrated by running some of the new algorithms in conventional short-pipelines for image analysis. In related papers, we have shown a pipeline architecture organization called PPPE (Parallel Pipeline Projection Engine), which unleashes the power of projection-based computer vision, image processing, and computer graphics. In the present correspondence, we deal with just a few of the many algorithms which can be supported in PPPE. These algorithms illustrate the use of the Radon transform as a tool for image analysis.     

基于VR的二维触发式碰撞检测算法

在虚拟场景中经常会用到虚拟现实技术设置某精灵的移动范围和区域, 物体与物体之间碰撞检测的算法成为技术关键, 常用的基于图形图像的算法虽然很有效应用范围广, 但是无事件处理能力, 并且执行效率低和占用大量的系统资源. 本文介绍一种利用二维数组高效的碰撞检测算法, 满足执行效率高但精度要求不高的碰撞检测.     

Incremental algorithms for collision detection between polygonalmodels

Fast and accurate collision detection between general polygonal models is a fundamental problem in physically based and geometric modeling, robotics, animation, and computer-simulated environments. Most earlier collision detection algorithms are either restricted to a class of models (such as convex polytopes) or are not fast enough for practical applications. The authors present an incremental algorithm for collision detection between general polygonal models in dynamic environments. The algorithm combines a hierarchical representation with incremental computation to rapidly detect collisions. It makes use of coherence between successive instances to efficiently determine the number of object features interacting. For each pair of objects, it tracks the closest features between them on their respective convex hulls. It detects the objects' penetration using pseudo internal Voronoi cells and constructs the penetration region, thus identifying the regions of contact on the convex hulls. The features associated with these regions are represented in a precomputed hierarchy. The algorithm uses a coherence based approach to quickly traverse the precomputed hierarchy and check for possible collisions between the features. They highlight its performance on different applications     

虚拟装配环境中碰撞检测算法的研究综述与展望

虚拟装配系统可对机电产品进行装配仿真,生成装配顺序与装配轨迹,而碰撞检测技术正是对装配顺序与装配轨迹的正确性进行验证。把虚拟装配环境的碰撞检测算法归类为:基于时间域的碰撞检测算法、基于几何空间的碰撞检测算法、基于图像空间的碰撞检测算法。对这几类算法的研究现状进行了综述,根据研究现状分析了碰撞检测算法中存在的问题及研究难点,并对碰撞检测算法的研究趋势进行了展望。