基于多媒体技术的三维人物图像动态重构

针对基于自标定的三维人物图像动态重构方法不能准确获取人物运动形态的三维位置,重构结果存在较高的偏差的问题,提出基于多媒体技术的三维人物图像动态重构方法,采用单目图像重构算法完成人体三维姿态重构。对多媒体技术中单摄像机拍摄的单目人体运动图像进行重构时,首先基于人体树状模型,采用基于部件检测器的二维肢体检测算法完成人体二维肢体检测;再采用基于关节点图像坐标的三维姿态重构算法,依据人体二维姿态检测结果,通过预测关节点反投影误差的退火粒子滤波算法完成人体三维姿态的跟踪,实现三维人体图像动态重构。实验结果说明,所提方法可准确实现三维人物图像动态重构,具有较高的重构精度和效率。     

目标高真实感红外图像生成方法

为满足仿真实验对高真实感目标红外图像的需求,提出了一种基于实测图像与三维数字仿真相结合的红外图像生成方法。通过测量获得物体表面实际辐射分布,以此为基础数据,建立真实温度分布的数学反演模型,生成目标红外纹理。再将纹理映射到几何模型,利用三维渲染技术生成高真实感红外图像。实验结果表明:该方法仿真灵活性高,生成的目标红外特征自然、准确,纹理细节丰富,图像实用性强。     

基于深度学习的多帧遥感降质图像三维重建算法

为提升多帧遥感降质图像对比度以及图像质量,提出一种基于深度学习的多帧遥感降质图像三维重建算法。采用三角函数变换方法并结合高通滤波器,增强多帧遥感降质图像对比度;再以包含生成器和判别器的生成对抗网络为基础,在判别器中引入自注意力层,设计自注意力机制残差模块,生成自注意力生成对抗网络模型;最后将增强后的图像输入模型进行学习和训练,获取多帧遥感降质图像的全局特征后,实现多帧遥感降质图像三维重建。测试结果表明,所提算法具有较好的多帧遥感降质图像增强能力,能够提升图像对比度,并且渗透指数（PI）均在0.92以上,重构效果良好。     

数字电影产业中三维图像重构技术改进

数字电影中图像具有动态性和帧分布随机性,导致图像重构的逼真度不好。传统方法采用小波重构方法,受到小波尺度选择准确性影响较大。为了改善数字电影画面重构的视觉效果,提出一种基于相邻帧补偿和电子稳像技术的数字电影产业中三维图像重构技术。对数字电影的图像画面进行像素特征点扫描,对扫描输出的特征点采用相邻帧差补偿方法进行模板匹配和边缘轮廓特征提取,提取数字电影图像中动态跳频特征点,对提取的特征点通过SIFT算法进行电子稳像处理,提高图像重构的画质。实验结果表明,采用该方法进行数字电影的三维图像重构,具有较好的图像画面输出效果,在3D和4D影像设计中具有应用前景。     

基于激光点云数据的三维运动图像重构技术北大核心CSCD

为了解决三维运动图重构时存在的重构测量距离与实际距离误差大、激光点云数据数量多和重构图像清晰度对比低的问题,提出了基于激光点云数据的三维运动图像重构技术,通过配准多帧激光点云数据,从中获取激光点云数据集,再采用平面拟合方法对激光点云数据集实行去噪处理,最后利用曲面重构法完成对曲面模型的拟合,实现三维运动图像重构。实验结果表明,通过对三维运动图像重构进行测量距离与实际距离的对比、激光点云数据数量的对比和测量图像与实际图像清晰度的对比测试,验证了三维运动图像重构技术的实用性高。     

交互式三维动画快速创作系统研究

在三维动画的创作阶段,传统的逐幅手工绘制方法,不仅费时费力,而且简单的笔画线条可能导致动画内容传达错误。充分利用了现代计算机图形、图像处理技术以及网络资源的优势,提出了交互式三维动画快速创作的新方法。整个系统包含两个子系统:导演脚本生成子系统和三维动画生成子系统。通过构建了基于Internet的多源可视媒体素材库,并采用了高层语义标注、图像及三维模型检索、图像分割、图像无缝融合、三维渲染等关键技术,实现了一套完整的动画快速创作系统。经实验测试证明和实际用户体验分析,该系统实现速度快、性能稳定、界面直观、操作便捷、可视化表达效果佳,能够很好地提高动画创作效率。     

基于虚拟现实技术的三维图像重构研究

针对传统基于主动偏振成像的三维图像重构方法重构过程中图像统计信息表达能力较差,导致重构后三维图像精度低,研究一种基于虚拟现实技术的三维图像重构方法。选取Visual C++可视化软件开发平台和VTK三维图像处理软件作为三维图像重构实现平台,将原始图像通过数据输入以及文件解析等步骤导入计算机后,对原始图像进行图像滤波、图像分割以及图像插值等预处理,处理后的图像在VTK软件中利用包围盒法先构建图像重构的三维数据场,依据图像重构三维数据场绘制图像三维直接体,通过图像三维直接体获取三维图像重构输出公式,实现基于虚拟现实技术的三维图像重构。仿真结果表明,采用该方法对10幅图像进行三维图像重构,重构图像平均遍历覆盖度高达97.99%,重构精度均高于97%。     

基于二维压缩感知的有意义图像加密算法研究

针对基于压缩感知的有意义图像加密算法存在加密图像视觉安全性不高及重构图像质量不佳的问题,提出了一种基于二维压缩感知的有意义图像加密算法。首先,设计了一种与明文相关联的混沌伪随机序列生成方法,利用全局随机置乱和灰度变换操作进行预加密,改进了重构图像质量。生成的预加密图像作为二维压缩感知的输入,在压缩加密和量化操作后,生成秘密图像。其次,考虑了待嵌入数据和待修改数据之间的关系,利用自适应嵌入方法修改载体系数值,提高了有意义加密图像的视觉安全性。最后,采用二维投影梯度重构方法联合执行解压缩和解密操作,获取重构图像。实验结果表明,与现有算法相比,所提算法不仅提高了加密图像视觉安全性和重构图像质量,而且能抵抗噪声和裁剪攻击。     

环形石英玻璃在二维投影图像中的成像模型

在发动机光学实验中,通常采用环形石英玻璃缸套代替金属缸套,在多个角度进行发动机燃烧火焰二维投影图像的拍摄,并利用CT技术重构燃烧火焰的三维图像。但受石英玻璃折射现象的影响,火焰的二维投影图像会发生改变,从而使火焰的三维重构图像产生畸变。本文主要从光学角度来分析不同半径的环形石英玻璃对物体二维投影图像产生的影响,建立相应的成像模型,并利用MATLAB语言进行仿真实现。该研究对建立ART代数方程组进行发动机火焰的切片重构具有很强的现实意义。     

基于真实感约束的VR虚拟人物图形生成方法改进研究

在对虚拟现实人物进行视景重构和三维重建中,为了提高虚拟人物图形生成的逼真性,需要结合图形与图像处理方法进行虚拟人物图形的三维跟踪渲染和重构,文章提出一种基于真实感约束的VR虚拟人物图形生成方法,采用图像边缘轮廓检测和纹理跟踪渲染方法进行虚拟人物图像采集和视景生成,并结合小波降噪方法对虚拟人物图形进行降噪滤波处理,提高人物图形成像的逼真度。在重构的像素特征空间中进行信息融合,为了提高VR成像的真实感,文章采用自适应纹理映射技术进行虚拟人物图形的跟踪渲染,将像素值加到三维实体模型上,生成具有真实感的VR虚拟人物图形。仿真结果表明,采用该方法进行VR虚拟人物图形生成的逼真度较好,输出图形的峰值信噪比较高,说明VR成像的质量较好,性能优于传统方法。     

三维激光扫描测量系统的三维图像数据压缩

三维彩色激光扫描测量系统是利用计算机视觉的原理对物体进行三维测量和重建,以获取物体的三维图像。三维图像的数据量很大,文中研究了三维图像的压缩策略和算法,采用三角形条带的网格压缩方法,以及顶点数据的编码方法,可以把三维图像的存贮空间减小到压缩前数据的１／６,从而有效地解决了测量系统在实际应用环境下的图像存贮和传输问题。     

3D structure extraction coding of image sequences

This paper presents a 3D structure extraction coding scheme that first computes the 3D structural properties such as 3D shape, motion, and location of objects and then codes image sequences by utilizing such 3D information. The goal is to achieve efficient and flexible coding while still avoiding the visual distortions through the use of 3D scene characteristics inherent in image sequences. To accomplish this, we present two multiframe algorithms for the robust estimation of such 3D structural properties, one from motion and one from stereo. The approach taken in these algorithms is to successively estimate 3D information from a longer sequence for a significant reduction in error. Three variations of 3D structure extraction coding are then presented — 3D motion interpolative coding, 3D motion compensation coding, and “viewpoint” compensation stereo image coding — to suggest that the approach can be viable for high-quality visual communications.     

Precision isosurface rendering of 3D image data

We address the task of rendering by ray tracing the isosurface of a high-quality continuous model of volumetric discrete and regular data. Based on first principles, we identify the quadratic B-spline as the best model for our purpose. The nonnegativity of this basis function allows us to confine the potential location of the isosurface within a binary shell. We then show how to use the space-embedding property of splines to further shrink this shell to essentially a single voxel width. Not all rays traced through a given shell voxel intersect the isosurface; many may only graze it, especially when the ray-tracing vantage point is close to or within the volume to be rendered. We propose an efficient heuristic to detect those cases. We present experiments to support our claims.     

BM3D frames and variational image deblurring

A family of the block matching 3-D (BM3D) algorithms for various imaging problems has been recently proposed within the framework of nonlocal patchwise image modeling , . In this paper, we construct analysis and synthesis frames, formalizing BM3D image modeling, and use these frames to develop novel iterative deblurring algorithms. We consider two different formulations of the deblurring problem, i.e., one given by the minimization of the single-objective function and another based on the generalized Nash equilibrium (GNE) balance of two objective functions. The latter results in the algorithm where deblurring and denoising operations are decoupled. The convergence of the developed algorithms is proved. Simulation experiments show that the decoupled algorithm derived from the GNE formulation demonstrates the best numerical and visual results and shows superiority with respect to the state of the art in the field, confirming a valuable potential of BM3D-frames as an advanced image modeling tool.     

基于VTK的医学图像三维重建研究

使用VTK工具包和MC重建算法开发了一套医学影像三维重建系统.由于重建后图像数据的处理时间和存储代价与三角形网格中三角形数量成正比, 过于复杂和细节化的网格会给图像数据的存储、传输、计算和实时绘制等带来负担, 故采用了顶点合并的三角形网格简化方法来减少三角形数量.     

Objective image quality assessment of 3D synthesized views

Depth-Image-Based-Rendering (DIBR) techniques are essential for three-dimensional (3D) video applications such as 3D Television (3DTV) and Free-Viewpoint Video. However, this process is based on 3D warping and can induce serious distortions whose impact on the perceived quality is far different from the one experienced in the 2D imaging processes. Since quality evaluation of DIBR-synthesized views is fundamental for the design of perceptually friendly 3D video systems, an appropriate objective quality metric targeting the assessment of DIBR-synthesized views is momentous. Most of the 2D objective quality metrics fail in assessing the visual quality of DIBR-synthesized views because they have not been conceived for addressing the specificities of DIBR-related distortions. In this paper, a new full-reference objective quality metric, 3DSwIM (3D Synthesized view Image Quality Metric), dedicated to artifacts detection in DIBR-synthesized view-points is presented. The proposed scheme relies on a comparison of statistical features of wavelet subbands of two input images: the original image and the DIBR-based synthesized image. A registration step is included before the comparison step so that best matching blocks are always compared to ensure “shifting-resilience”. In addition, a skin detection step weights the final quality score in order to penalize distorted blocks containing “skin-pixels” based on the assumption that a human observer is most sensitive to impairments affecting human subjects. Experimental tests show that the proposed method outperforms the conventional 2D and DIBR-dedicated quality metrics under test.     

Object-based coding of stereoscopic and 3D image sequences

The author begins by discussing what object based coding is and goes on to consider the structure of object based stereoscopic coders. Different techniques for object-based stereoscopic image sequence coding are reviewed. These techniques basically differ in the way they define models and estimate model parameters. We review the various models used for representing motion and structure. Then we review segmentation techniques, and discuss coding of object parameters and image synthesis     

基于3D模型的双色红外图像仿真研究

基于商用动画和效果软件Maya输出Wavefront OBJ文件造型数据,结合仿真对象的热传递模型和红外传感器模型．高细节地实现了基于3D模型的双色红外图像仿真。仿真结果满足红外图像自动目标识别系统(ATR)的设计需求,为目标识别算法的验证提供了丰富可靠的仿真图像数据。最后给出了使用C 语言和Open GL在Microsoft Windows平台的仿真结果。