3DS MAX中体视动画生成模块的实现

介绍了体视动画的生成方法，讨论了如何基于流行的三维动画软件3DS MAX开发体视动画的生成模块。最后给出了建筑动态模拟体视动画中的一帧图像。     

体视动画的生成与处理系统

该文介绍了一个体视动画的生成与处理系统。利用这个系统,可以自动将流行动画软件生成的动画转换成双视点体视动画,然后将渲染得到的两个序列动画自动合成,形成符合于液晶眼镜观察的动画图像。该系统可以帮助开发各种动态图形仿真系统。     

实用虚拟现实中体视动画的实现

该文讨论了基于PC机的实用虚拟现实系统开发平台，介绍一种基于PC机的实用虚拟现实技术中硬件结构实现的方法。在深入研究3DS MAX的基础上，推导出适用于3DS MAX的体视动画的自动生成算法，并给出体视动画生成模块的程序流程，最后根据研究的结果，做出了一组具有体视效果的实例。     

基于多视点的裸眼体视动画技术研究与应用

为有效解决裸眼体视动画片源紧缺的市场现状,改善可视角度受限的关键问题,提出了开发基于多视点的3dsMax 2010裸眼体视动画插件。根据裸眼体视动画技术流程,设计多视点摄像机阵列模型来实现三维动画的多视点数据获取,在此基础上,利用多视点采样合成算法进行多帧渲染合成。实验通过与双视点裸眼体视动画进行比较,验证了利用插件生成的多视点裸眼体视动画可视角度增大,对于多人多角度观看、拓展虚拟三维软件的立体显示功能具有现实意义。     

微机立体动画研究及体视误差分析

非交互式虚拟现实主要是在视觉上达到三维逼真视感，本文分析了时分隔式立体动画对计算机系统的要求以及当前在微机上实现的可能性，提出了一种利用３ＤＳ动画软件在微机上生成时分隔式立体动画片的方法，推导了这种立体显示方式的数学模型，并以此对其体视误差作了分析。     

基于上下文块的隐空间图像动画技术

图像动画方法通常是指将驱动视频的运动“复制”给源图像,使源图像获得与驱动视频相同的运动,让静止图像动起来。然而,以往的图像动画方法通常需要提取标签、光流、语义图等结构信息,如果源图像和驱动视频具有较大的外观变化,就会难以保留源图像的身份信息,生成伪影和错误的运动。基于此,提出了基于上下文块的自监督隐空间图像动画方法,通过隐空间中的线性导航使图像动画,由隐空间编码的线性位移来生成驱动视频的运动。在编码部分引入上下文模块能够更加准确地对源图像和驱动图像进行编码,生成准确真实的图像动画。实验分析表明,该模型在VoxCeleb2、Celeb-V2和Ted-talk谈话数据集上系统地和显著地优于其他方法。     

体视动态模拟中的图象生成与合成

该文介绍了体视动态模拟系统的硬件结构和体视动态图象的基本原理。在此基础上,给出了体视动态图象的生成方法。生成体视图象后需要对图象进行合成处理,这里分别介绍了补色体视图合成中的颜色处理方法和适用于新型立体眼镜的图象合成方法。     

三种体视图像生成方法的比较研究

简要介绍了生成体视图像的3种方法，平移，柱面变换和球面变换，并着重对同一方法取不同参数生成的体视图像效果以及3种方法生成的较好体视图像效果进行了比较，以得到较好的算法及较好的参数匹配，并对算法指出了改进方向。     

有效的非真实感动画生成方法

作为一种独特的动画表现形式,非真实感动画通常不需要精确的三维模型和光照模型,但又需要普通用户能方便地生成简单的非真实感动画。根据这一需求,将定向滤波技术与非真实感动画相结合:将源图像与一对正交的定向滤波进行卷积运算,得到一对奇偶滤波图像,反复改变它们的相位生成一系列不同相位的图像,使图像中的对象产生视觉上的动态效果,从而方便生成非真实感动画。     

基于深度学习和表情AU参数的人脸动画方法

为了利用计算机方便快捷地生成表情逼真的动漫人物,提出一种基于深度学习和表情AU参数的人脸动画生成方法.该方法定义了用于描述面部表情的24个面部运动单元参数,即表情AU参数,并利用卷积神经网络和FEAFA数据集构建和训练了相应的参数回归网络模型.在根据视频图像生成人脸动画时,首先从单目摄像头获取视频图像,采用有监督的梯度下降法对视频帧进行人脸检测,进而对得到的人脸表情图像准确地回归出表情AU参数值,将其视为三维人脸表情基系数,并结合虚拟人物相对应的24个基础三维表情形状和中立表情形状,在自然环境下基于表情融合变形模型驱动虚拟人物生成人脸动画.该方法省去了传统方法中的三维重建过程,并且考虑了运动单元参数之间的相互影响,使得生成的人脸动画的表情更加自然、细腻.此外,基于人脸图像比基于特征点回归出的表情系数更加准确.     

Viewpoint image generation for head tracking 3D display using multi‐camera and approximate depth information

A simple and high image quality method for viewpoint image synthesis from multi‐camera images for a stereoscopic 3D display using head tracking is proposed. In this method, slices of images for depth layers are made using approximate depth information, the slices are linearly blended corresponding to the distance between the viewpoint and cameras at each layer, and the layers are overlaid from the perspective of viewpoint. Because the linear blending automatically compensates for depth error because of the visual effects of depth‐fused 3D (DFD), the resulting image is natural to observer's perception. Smooth motion parallax of wide depth range objects induced by viewpoint movement for left‐and‐right and front‐and‐back directions is achieved using multi‐camera images and approximate depth information. Because the calculation algorithm is very simple, it is suitable for real time 3D display applications.     

一种基于3维全景图像技术的深度测量方法

3维全景图像技术是一种能够记录和显示全真3维场景的图像技术。该技术采用微透镜阵列记录空间场景，空间任意一点的深度信息只需通过一次成像即可直接获得。本文研究采用全景图像技术直接获取物体空间信息的方法。此方法首先从全景图像中抽提视图。视图是通过抽提全景图像中对应于每个微透镜下同一局部位置的点人工合成的。每幅视图包含了全景图像中对原来的物空间场景按照某一特定方向的平行投影记录信息。接下来通过分析全景图像的光学成像过程。推导了用来描述物体深度信息和其在对应的视图间的视差关系的深度方程。从而得出空间任一点的深度可以通过其在对应视图间的视差来求得。最后，通过运用全景图像测量火柴盒的厚度的实例，验证了这一方法的可行性。其结果一方面可用于全景图像的数据处理本身，另一方面可望为开发新型的深度测量工具提供理论依据。     

一种基于双向互匹配的视差图算法

提出一种视差图生成算法,利用左图像和右图像双向互匹配的的方法,从图像中获取左-右和右-左的视差图和梯度场,接着采用Winner-Take-All策略,对两幅视差图像进行匹配,得到初始视差图。最后,对视差图上存在的误匹配点进行优化。通过实验验证,该算法能够有效地提高匹配视差图的准确度。     

Performance improvement for additive light field displays with weighted simultaneous algebra reconstruction technique and tracked views

Additive light field displays are transparent autostereoscopic three-dimensional displays without backlights, thus suitable for augmented reality applications. However, when the parallax between viewpoint images becomes large with the increase of viewing angle, the optimization algorithm is hard to handle too many dissimilarities evenly on all viewpoints, resulting in poor reconstructed quality. This paper presents an additive light field display using the weighted simultaneous algebraic reconstruction technique with viewing angle-dependent weight distribution functions. We constrain the optimization to deliver a reconstructed light field of high image quality for viewpoints of large weight. When the proposed method is applied, with a wide dynamic viewing angle of 57° × 43°, the tracked views' peak signal-to-noise ratio exceeds 30 dB with only two additive display layers.     

Virtual toed‐in camera method to eliminate parallax distortions of stereoscopic images for stereoscopic displays

Abstract— The parallax images captured by a toed‐in camera have positive and negative horizontal parallax for stereoscopic displays, but they also have parallax distortions including horizontal and vertical distortions. The virtual toed‐in camera method can eliminate the horizontal distortion and reduce the vertical distortion. The parallax formulae for the corrected‐parallax images were deduced. The experiments were carried out and the results proved that the method was accurate. Good stereoscopic images without horizontal distortion and with little vertical distortion were presented on an autostereoscopic display.     

基于视差的高分辨率遥感影像建筑物变化检测

针对城区高分辨率遥感影像建筑物变化检测中视差引起误检测问题，提出一种基于视差的建筑物变化检测方法。首先，利用改进的双峰分裂法实现对建筑物阴影的检测；然后，借助阴影估计屋顶的位置，并自动选取种子区域，结合区域生长法进行建筑屋顶提取；最后，以视差、视差方位角以及面积等作为判定条件对两时相影像建筑物的变化情况进行分析。通过对WorldView-2影像和IKONOS影像进行变化检测，平均正确率达到了89.6%。实验结果表明:在屋顶光谱均匀且有明显建筑阴影的稀疏建筑区，该方法能够有效解决建筑屋顶种子区域自动选取及高层建筑视差引起误检测等难点问题。     

Automatic sensor placement for model-based robot vision.

This paper presents a method for automatic sensor placement for model-based robot vision. In such a vision system, the sensor often needs to be moved from one pose to another around the object to observe all features of interest. This allows multiple three-dimensional (3-D) images to be taken from different vantage viewpoints. The task involves determination of the optimal sensor placements and a shortest path through these viewpoints. During the sensor planning, object features are resampled as individual points attached with surface normals. The optimal sensor placement graph is achieved by a genetic algorithm in which a min-max criterion is used for the evaluation. A shortest path is determined by Christofides algorithm. A Viewpoint Planner is developed to generate the sensor placement plan. It includes many functions, such as 3-D animation of the object geometry, sensor specification, initialization of the viewpoint number and their distribution, viewpoint evolution, shortest path computation, scene simulation of a specific viewpoint, parameter amendment. Experiments are also carried out on a real robot vision system to demonstrate the effectiveness of the proposed method.     

Relationship between parallax and spatial resolution on visual comfort of an autostereoscopic display

A primary reason for visual discomfort caused by viewing 3D contents in autostereoscopic displays is the conflict between accommodation and convergence. Parallax directly affects the degree of conflict. In this paper, three factors are investigated—parallax magnitude, changing parallax, and spatial resolution—which are supposed to exert substantial influence upon visual comfort. The aforementioned three factors are integrated into stereoscopic sequences generated by software. With the data on the subjective evaluation of comfort from the viewers, statistical method is used to obtain both the main effects and interactions among the three factors. According to the experimental results, changing parallax might play a more crucial role in visual comfort than parallax magnitude. Spatial resolution might alleviate the negative effects in which changing parallax brings about. The experiment indicates that parallax for autostereoscopic displays should be within 50′ in consideration of comfort.     

Global Illumination as a Combination of Continuous Random Walk and Finite-Element Based Iteration

The paper introduces a global illumination method that combines continuous and finite-element approaches, pre-serving the speed of finite-element based iteration and the accuracy of continuous random walks. The basic idea is to decompose the radiance function to a finite-element component that is only a rough estimate and to a difference component that is obtained by Monte-Carlo techniques. Iteration and random walk are handled uniformly in the framework of stochastic iteration. This uniform treatment allows the finite-element component to be built up adap-tively aiming at minimizing the Monte-Carlo component. The method is also suited for interactive walkthrough animation in glossy scenes since when the viewpoint changes, only the small Monte-Carlo component needs to be recomputed.