增强视觉 | 计算机视觉 增强现实

Paul Debevec, Tim Hawkins, John Monosand Mark Sagar以他们创造的light stage获得了2010的奥斯卡sci-tech奖。light stage为本杰明巴顿奇事，阿凡达， 哈利波特等等电影贡献良多。

light stage是以Paul Debevec在2000年的siggraph的研究基础上发展起来的捕捉重建技术，目标是通过计算机图形，计算机图像等重建出有着高度真实感的人脸。主要思路是通过不同方向，强度的光照照亮的演员的脸部图像，来重建以假乱真的虚拟人脸。下面是lightstage 1的样子，现在看来很山寨。

下面是siggraph论文链接和项目主页。

Acquiring the Reflectance Field of a Human Face:
(Research Paper) (Project Web Page)

在light stage 1的基础上，相继发展出了light stage 2， 3， 4， 5，6代！下面是light stage 家谱。

• Light Stage 1:
  • Acquiring the Reflectance Field of a Human Face, SIGGRAPH 2000
  • Facial Reflectance Field Demo, SIGGRAPH 2000 Creative Applications Laboratory
  • Realistic Human Face Scanning and Rendering, ICT Graphics Lab 2001
• Light Stage 2:
  • A Photometric Approach to Digitizing Cultural Artifacts, VAST 2001
  • Reflectance Field Rendering of Human Faces for “Spider-Man 2″, SIGGRAPH 2004 Sketch
• Light Stage 3:
  • A Lighting Reproduction Approach to Live-Action Compositing, SIGGRAPH 2002
  • Optimizing Color Matching in a Lighting Reproduction System for Complex Subject and Illuminant Spectra, EGSR 2003
• Light Stage 5:
  • Postproduction Re-Illumination of Live Action Using Interleaved Lighting, SIGGRAPH 2004 Poster
  • Rapid Acquisition of Specular and Diffuse Normal Maps from Polarized Spherical Gradient Illumination, EGSR 2007
• Light Stage 6:
  • Relighting Human Locomotion with Flowed Reflectance Fields, EGSR 2006 Paper
  • A Reflective Light Stage, ICT Technical Report 2006 Paper
  • A Dual Light Stage , EGSR 2005 Paper

到了light stage 5已经酷多了。看图。

avatar中逼真的外星人就是weta digital和ict light stage 5合力打造的。（插一句，weta digitall是新西兰导演peter jackson，也就是指环王，金刚的导演效仿前辈卢卡斯创建的视觉特效公司）。

现在的state of art是light stage 6，看下图，光装置就够炫了。目标是从人脸扩展到人体。看下图。

下面是Paul Debevec在TED上面的演讲。

来源：HDRI，fxguide，ict light stage 主页

啥也不说了，直接猛击进去看视频吧。眼泪哗哗的。一定要看啊。

http://gl.ict.usc.edu/Research/3DDisplay/

The system works by projecting high-speed video onto a rapidly spinning mirror. As the mirror turns, it reflects a different and accurate image to each potential viewer. Our rendering algorithm can recreate both virtual and real scenes with correct occlusion, horizontal and vertical perspective, and shading.

此技术来自USC ICT，获得了siggraph2007 “Best Emerging Technology”。

作者之一是 Paul Debevec，siggraph97低动态图像（LDR）创建高动态图像（HDR）的发明人。