Perception-based animation rendering

In most currently produced computer generated animation there is significant visual information that is literally never seen because of the characteristics of the human visual system. By tailoring the rendering of animation images to match the characteristics of human visual perception, significant computational and image storage savings can be obtained while retaining perceived animation quality. Vision research indicates that the human visual system processes two information channels. The transient channel rapidly processes low spatial resolution full colour information. The sustained channel processes high spatial resolution luminance information at a much slower rate. This paper discusses how the rendering of animation images can be accomplished to match these perception characteristics and achieve significant savings while maintaining animation quality. Computation and storage savings of up to 80 per cent are possible. Several animation segments have been produced to demonstrate the viability of this approach.     

Perception-based model simplification for motion blur rendering

Motion blur effects are important to motion perception in visual arts, interactive games and animation applications. Usually, such motion blur rendering is quite time consuming, thus blocking the online/interactive use of the effects. Motivated by the human perception in relation to moving objects, this paper presents simplified geometric models that enable to speedup motion blur rendering, which has not been tracked in motion blur rendering specifically. We develop a novel algorithm to simplify models with motion-aware, to preserve the features whose characteristics are perceivable in motion. We deduce the formula to outline the level of detail simplification by the object moving velocity. Using our simplified models, methods for motion blur rendering can achieve the rendering quality as using the original models, and obtain the processing acceleration mostly. The experimental results have shown the effectiveness of our approach, more acceleration with the larger models or faster motion (e.g. for the dragon model with over a million facets, the motion-blur rendering via hierarchical stochastic rasterization is sped up by over 27 times).     

一种二维矢量图形的硬件优化渲染算法

提出了一种适用于嵌入式设备的二维矢量图形硬件优化渲染算法。在采用超采样反锯齿模式下,该算法中每个像素点只使用一个方向权重计数器,而并非以往算法中每个像素点使用多个计数器,从而达到节省硬件资源,并大幅减少渲染所需计算量的效果。实验结果表明,和以往算法相比,在8-queen超采样模式和XVGA显示大小下,能节省83%的存储器使用量和65%的存储器访问量,并且能取得较好的反锯齿效果。     

Hamiltonian triangulations for fast rendering

High-performance rendering engines are often pipelined; their speed is bounded by the rate at which triangulation data can be sent into the machine. An ordering such that consecutive triangles share a face, which reduces the data rate, exists if and only if the dual graph of the triangulation contains a Hamiltonian path. We (1) show thatany set ofn points in the plane has a Hamiltonian triangulation; (2) prove that certain nondegenerate point sets do not admit asequential triangulation; (3) test whether a polygonP has a Hamiltonian triangulation in time linear in the size of its visibility graph; and (4) show how to add Steiner points to a triangulation to create Hamiltonian triangulations that avoid narrow angles.     

Single-strips for fast interactive rendering

Representing a triangulated two manifold using a single triangle strip is an NP-complete problem. By introducing a few Steiner vertices, recent works find such a single-strip, and hence a linear ordering of edge-connected triangles of the entire triangulation. In this paper, we extend previous results [10] that exploit this linear ordering in efficient triangle-strip management for high-performance rendering. We present new algorithms to generate single-strip representations that follow different user defined constraints or preferences in the form of edge weights. These functional constraints are application dependent. For example, normal-based constraints can be used for efficient rendering after visibility culling, or spatial constraints for highly coherent vertex-caching. We highlight the flexibility of this approach by generating single-strips with preferences as arbitrary as the orientation of the edges. We also present a hierarchical single-strip management strategy for high-performance interactive 3D rendering.     

HLODs模型在场景快速绘制中的应用

论述了一种基于视相关分级细节层次的场景简化的算法，加速场景绘制速度。预处理阶段利用八叉树构造场景的分层次结构；实时渲染阶段，采用多线程进行场景的实时绘制：根据视点进行可见性剔除，根据屏幕误差选择合理的分级细节层次，利用数据管理调度进行数据的实时更新。在保持图像的保真度条件下，可实现场景的快速绘制。     

Multiresolution and fast decompression for optimal web-based rendering

Limited bandwidth is a strong constraint when efficient transmission of 3D data to Web clients and mobile applications is needed. In this paper we present a novel multi-resolution WebGL based rendering algorithm which combines progressive loading, view-dependent resolution and mesh compression, providing high frame rates and a decoding speed of million of triangles per second in JavaScript. The method is parallelizable and scalable to very large models.The algorithm is based on the local multi-resolution approaches provided by the community, but ad-hoc solutions had to be studied and implemented to provide adequate performances. In particular, a compression mechanism that reached very high compression rate without impact on rendering performance was implemented. Moreover, the data partition strategy was modified in order to be able to load different types of data (i.e. point clouds) and better adapt to the potentials and limitations of web-based rendering.     

Splatting errors and antialiasing

The paper describes three new results for volume rendering algorithms utilizing splatting. First, an antialiasing extension to the basic splatting algorithm is introduced that mitigates the spatial aliasing for high resolution volumes. Aliasing can be severe for high resolution volumes or volumes where a high depth of field leads to converging samples along the perspective axis. Next, an analysis of the common approximation errors in the splatting process for perspective viewing is presented. In this context, we give different implementations, distinguished by efficiency and accuracy, for adding the splat contributions to the image plane. We then present new results in controlling the splatting errors and also show their behavior in the framework of our new antialiasing technique. Finally, current work in progress on extensions to splatting for temporal antialiasing is demonstrated. We present a simple but highly effective scheme for adding motion blur to fast moving volumes     

Hardware Assisted Fast Volume Rendering with Boundary Enhancement

In this paper,a new volume rendering method with boundary enhancement is presented.The boundary is extracted and represented by surfaces explicitly,Then,using 3D texture mapping and graphics acceleation hardware,the volume data can be rendered with controllable boundary shading effect almost in real time.Test shows that this method is 4-5 times faster than the previous methods.Moreover,it can also be extended to render the surfaces and the volumetric data together interactively.     

Hardware-assisted polygon antialiasing

The use of two sampling methods, the precise point-sampling algorithm and the extended Bresenham algorithm (EBA), for rendering hardware is discussed, showing where the two methods converge and diverge. Two antialiasing techniques are then presented: an oversampling method and a stochastic method. Practical application of both is described. The use of filtering and sophisticated features with these methods is considered. Hardware support for antialiasing of polygons is discussed     

大规模数据快速体绘制方法的设计与实现

体绘制是科学计算可视化的重要手段,针对大规模数据场体绘制计算量大、效率低的问题,提出一种基于哈尔小波变换的三维规则网格数据场快速体绘制方法.采用整体描述、局部细化的策略对转换后的数据进行组织、管理和调度,实现了多尺度分析和快速随机存取,并有效解决了CPU在处理大规模数据集时纹理内存的局限;采用基于CUDA(计算统一设备架构)的GPU加速技术提高体绘制算法性能,很好的实现了大规模数据集的交互式可视化.     

GPU实现的快速分层地形渲染算法

随着GPU性能的飞速提升,越来越多的地形渲染算法能够完全由GPU实现.本文提出了一种新的完全基于GPU的地形渲染算法.该算法使用顶点着色器完成中间数据生成,在几何着色器中使用之前生成的信息完成地形的LOD操作和网格的动态生成.该算法不仅具有易于在GPU上实现的特点,同时能够提供无缝的、自适应地形起伏的渲染效果.这也顺应了图形学的主流:将图形计算或对几何体的操作从CPU转移到GPU上,从而做到无需CPU的干预,降低数据传输量,节约通信带宽的目的.实验证明,该算法适合于处理较大规模地形块.     

基于动态Impostor技术的树木快速绘制方法

树木快速绘制技术研究一直以来都是计算机图形绘制的一个热点领域,因为树木复杂的细节结构使其在绘制上存在着相当大的困难.提出了一种基于动态impostor技术的树木绘制方法,不仅可以快速地绘制树木,而且具有较高的真实感效果.该方法首先基于树木模型进行平面投影去创建impostor平面,然后将纹理映射到已经创建好的impostor平面上,最后通过绘制impostor纹理平面形成树木图像.当参考视点移动时,可以根据误差来决定是否动态更新impostor平面的内容.     

Pooling spike neural network for fast rendering in global illumination

Neural Computing and Applications - The generation of photo-realistic images is a major topic in computer graphics. By using the principles of physical light propagation, images that are...     

Perception-based fuzzy sets for visual texture modelling

Texture is one of the most used low-level features for image analysis and, in addition, one of the most difficult to characterize. Although there is not an accurate definition for the concept of texture, it is usual for humans to describe visual textures according to some perceptual properties like coarseness, directionality, contrast, line-likeness or regularity. In this paper, we propose to model texture on the basis of its perceptual properties. To do this, fuzzy sets defined on the domain of some of the most representative measures of each property are employed. This approach achieves a double objective: first, to obtain models that allow to represent the imprecision related to texture properties, and second, to identify the most appropriate measure for each of these properties. In order to define the fuzzy models, parametric membership functions are proposed, where the corresponding parameters are obtained by learning a functional relationship between the computational values given by the measure and the human perception of the corresponding property. The performance of each fuzzy set is analyzed and checked with the human assessments, and a ranking of measures is obtained according to their ability to represent the perception of the property, allowing to identify the most suitable measure. In order to explain the proposed methodology, we focus our study on coarseness, contrast and directionality, that are considered the three most important texture properties.     

A practical and fast rendering algorithm for dynamic scenes using adaptive shadow fields

Recently, a precomputed shadow fields method was proposed for achieving fast rendering of dynamic scenes under environment illumination and local light sources. This method can render shadows fast by precomputing the occlusion information at many sample points arranged on concentric shells around each object and combining multiple precomputed occlusion information rapidly in the rendering step. However, this method uses the same number of sample points on all shells, and cannot achieve real-time rendering due to the rendering computation rely on CPU rather than graphics hardware. In this paper, we propose an algorithm for decreasing the data size of shadow fields by reducing the amount of sample points without degrading the image quality. We reduce the number of sample points adaptively by considering the differences of the occlusion information between adjacent sample points. Additionally, we also achieve fast rendering under low-frequency illuminations by implementing shadow fields on graphics hardware.     

An efficient clustering method for fast rendering of time-varying volumetric medical data

Visualization and exploration of time-varying volumetric medical data help clinicians for better diagnosis and treatment. However, it is a challenge to render these data in an interactive manner because of their complexity and large size. We propose an efficient clustering method for fast compression and rendering of these large dynamic data. We divide the volumes into a set of blocks and use a BIRCH (Balanced Iterative Reducing and Clustering using Hierarchies) based algorithm to cluster them, which can usually find a high quality clustering with a single scan of the blocks. In addition, the granularity of clusters can be adaptively adjusted by dynamically configuring threshold values. In each cluster of blocks, a KeyBlock is generated to represent the cluster, and therefore the storage space of the volumes is reduced greatly. In addition, we assign a lifetime to every KeyBlock and implement a dynamic memory management scheme to further reduce the storage space. During the rendering, each KeyBlock is rendered as a KeyImage, which can be reused if the view transformation and transfer function are not changed. This reuse can help to increase the rendering speed significantly. Experimental results showed that the proposed method can achieve good performance in terms of both speed optimization and space reduction.