基于LED背景墙的电影虚拟化制作中摄影机跟踪技术研究

电影虚拟化制作技术是近年来提出的一种新型影视制作技术,随着其发展和创作需求的提升,电影虚拟化制作不断推陈出新,制作方式也由最初的基于绿幕的虚拟化制作发展到近两年最新提出的概念——基于LED背景墙的虚拟化制作技术.摄影机跟踪系统是虚拟化制作的前提,本文依托北京电影学院影视技术系与青年电影制片厂联合建设的LED电影虚拟化制...     

在轨光学相机探测图像数字仿真系统设计与实现

根据在轨光学相机测量原理与工作环境,建立了空间目标相对运动学与反射光学特征模型、相机成像模型以及背景恒星成像模型;分析了相机测量噪声及相机探测灵敏度并在仿真中考虑了对干扰因素成像质量的影响,完成了现有星表中背景恒星的视星等根据相机的探测波段范围进行了仪器星等的等效计算,以提高仿真图像的逼真度;根据相机工作原理设计了仿真流程,应用Visual C++与Open GL技术完成了仿真软件的实现。     

一种简单的摄像机标定技术在视觉定位中的应用

摄像机标定技术对于精确的双目视觉定位起着关键的作用。了解摄像头标定的原理有助于采用合理方法减小标定结果误差。本文介绍的摄像机标定方法标定结果误差小。摄像机标定过程中用到三个坐标系,它们之间的转换关系是摄像机标定的基础。采用内外参数分离的标定方法,通过具体实验分步标定了摄像机的内参数和外参数,实验过程简单,标定精度较高。     

DMCⅡ数码影像在大比例尺地形测绘中的应用

DMC Ⅱ数码航摄仪是Digital Mapping Camera的第二代产品,本文介绍了DMCⅡ数码影像的主要情况及相关参数,并与DMCⅠ进行相应比较,阐述了DMCⅡ数码影像的特点、优势及不足。以实际测绘生产项目为例,详细介绍了利用DMCⅡ数码影像在大比例尺地形测绘中的应用情况,对测绘成果的质量进行了统计分析。     

网络摄像机软件架构的研究与设计

为网络摄像机制定一个统一的应用软件框架。将前端设备软件分为平台软件和硬件支持库两个部分。所有前端设备采用统一的平台软件,支持前端设备的各种应用需求,包括视频采集、数据传输、远程参数配置、本地参数配置(GUI)、录像存储、云镜控制、告警处理、Web网管等功能。通过研究和项目实践表明,这种新的软件系统结构技术方案,可被广泛用于各种接入平台,很好地解决了以上问题。     

A robust omnidirectional vision sensor for soccer robots

How to make robot vision work robustly under varying lighting conditions and without the constraint of the current color-coded environment are two of the most challenging issues in the RoboCup community. In this paper, we present a robust omnidirectional vision sensor to deal with these issues for the RoboCup Middle Size League soccer robots, in which two novel algorithms are applied. The first one is a camera parameters auto-adjusting algorithm based on image entropy. The relationship between image entropy and camera parameters is verified by experiments, and camera parameters are optimized by maximizing image entropy to adapt the output of the omnidirectional vision to the varying illumination. The second one is a ball recognition method based on the omnidirectional vision without color classification. The conclusion is derived that the ball on the field can be imaged to be an ellipse approximately in our omnidirectional vision, and the arbitrary FIFA ball can be recognized by detecting the ellipse imaged by the ball. The experimental results show that a robust omnidirectional vision sensor can be realized by using the two algorithms mentioned above.     

Recognizing jump patterns with physics-based validation in human moving trajectory

This paper presents an approach to recognize jump patterns in human moving trajectory, differentiating jump tracks from planar moving tracks. Since human moving trajectory is one of the most informative representations for content understanding and event detection, trajectory-based video analysis has been gaining popularity. However, a jump action typically leads to violent change in human moving trajectory, since the person suddenly leaves the original plane on which he/she has been moving. The abnormal tracks of the trajectory would influence the performance of trajectory-based video analysis. Hence, differentiating jump tracks from planar moving tracks is of vital importance, not to mention that jump actions typically imply significant events, especially in sports games. In this paper, volleyball videos are used as case study to demonstrate the effectiveness of our proposed jump pattern recognition approach. We derive player trajectory by head tracking, analyze the movement of each player, and recognize potential jump tracks in player trajectories based on two important characteristics: (1) jumps cause pulse-like tracks in the trajectory and (2) the extensions of such tracks go through the vanishing point of vertical lines in the scenes. Finally, the jump positions/heights are estimated, in addition to the planar moving trajectory of each player on the court ground. The experiments show that satisfactory results can be obtained with the proposed recognition scheme.     

基于仿射变换和透视投影的摄像机镜头畸变校正方法

依照摄像机成像过程,提出了一种方便快捷的摄像机镜头畸变精确校正方法。基于逆向摄像机镜头校正模型、仿射变换和透视变换,推导了从标准靶标图像坐标到理想图像坐标之间的精确函数关系,采用最小二乘估计对畸变参数求解,利用双线性插值法还原理想图像,并给出了详细的实验过程和实验结果。结果表明,该方法具有对实验条件要求低、算法运行速度快、校正结果精确等特点,适用于自动实时校正环境。     

摄像定尺系统在莱钢连铸机中的应用

介绍了摄像定尺系统的组成、控制原理、系统功能以及在连铸机中的应用效果。有效的提高了连铸机生产线板坯长度的精确性。     

基于立体视觉的移动机器人自主导航定位系统

描述了一种基于立体视觉的移动机器人自主导航定位系统。该系统采用双目立体视觉完成环境特征的3D信息提取,实时计算出机器人相对作业目标的位姿（6D）关系,导引移动机器人控制系统按目标异向进行运动。系统在相对位姿计算中采用旋动（Screw）理论,将带约束的多变量函数的非线性优化问题转化为线性方程组的最小二乘问题,简化了计算复杂性。实验表明,这个导航定位系统在定位精度和数据处理速度上均可满足机器人导航的要求。