【作者】 冯永明；

【导师】 杨东勇；

【作者基本信息】 浙江工业大学 ， 计算机软件与理论， 2007， 硕士

【摘要】 基于反射镜面的全方位视觉是一项新兴的视觉技术,该视觉系统能一次性的获取水平方向360°的场景图像,与传统视觉系统相比具有视野大的优点,非常适合在实时监控等领域的应用。单张全方位图像包含了水平一周的场景信息,存在严重的扭曲现象,在应用中需要从全方位图像中恢复出所拍摄的景物信息。本文首先介绍了全方位视觉技术的研究和应用现状。通过对双曲镜面全方位视觉系统中几何光路的分析,详细地阐述了全方位视觉图像的成像过程和使用单张全方位图像展开获得全景图以及透视图的方法。在展开过程中,使用传统的近邻取样法容易造成展开图像素点不连续,展开质量较差,尤其是对于分辨率不高的全方位图。本文在展开的逆投影坐标变换过程中引入了双线性内插值法,提高了展开质量。并根据逆投影坐标变换公式特点,引入了三角函数查表法,减少了大量三角函数的重复运算,提高了展开性能。全方位视觉展开运算量巨大,而且操作系统在多媒体处理上会占用较多CPU,两者容易使性能成为全方位视觉展开过程中的一个瓶颈。本文作者开发了用于将全方位图展开成全景图的DirectShow过滤器,使用该过滤器可以充分利用显卡的加速功能,发挥显卡的性能,减少CPU的占用率,达到更流畅的全方位视频展开回放效果。使用本文开发的过滤器,开发了基于DirectShow的全方位视觉展开软件平台,实现了对全方位图像、全方位视频文件、全方位实时视频流展开成全景图和透视图等功能。本文详细阐述了该软件的设计方法、具体实现,并简要介绍了软件的操作及性能。更多还原

【Abstract】 Omnidirectional vision is a vision system based on reflector,which captures scene of 360 degrees level direction once.Compared with traditional vision system,omnidirectional vision is of wider view that is suitable for various applications in real-time surveillance fields.One omnidirectional image contains information of one level circle scene, however the image is seriously distorted,which isn’t capable for practice application unless the scene information can be correctly extracted from omnidierectional image.Firstly,current research and applications of omnidierectional vision technology are introduced.Through specific analysis of geometry light routing in hyperboloid omnidirectional vision system,imaging process of omnidirectional vision is explained in detail,and technique for unwrapping one omnidirectional image to get panorama image and rendering is brought up in this paper.In unwrapping process,traditional methods easily make image pixel discontinuous which causes low image quality,especially for low resolution omnidirectional image.In this paper,quadratic interpolation method is applied for athwart projection transform,which improves image quality.According to athwart projection formula,trigonometric function table-checking method is induced,based on which,massive trigonometric function operation complex is reduced and unwrapping performance is improved.Because the process of omnidirectional vision unwrapping contains complex operation,on the other side,multimedia process makes OS costs plentiful CPU.Both of above will be a bottleneck for omnidirectional vision unwrapping process.Aiming at this bottleneck,DirectShow filter for unwrapping omnidirectional image is designed and implemented.The filter makes full use of graphics card acceleration promising higher performance of graphics card,cost less CPU,what makes the unwrapped panorama video playback more fluent.Omnidirectional vision platform,based on DirectShow filter developed in this paper,implements functions of unwrapping omnidirectional image,video,and real-time video stream to panorama or perspective images.The design and specific implementation,including operations of software and performance evaluation,are explained simply.更多还原