The Geometry of First-Returning Photons for Non-Line-of-Sight Imaging
The Geometry of First-Returning Photons for Non-Line-of-Sight Imaging
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DOI：
10.1109/cvpr.2017.251
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发表时间：
2017-07
期刊：
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通讯作者：
Chia-Yin Tsai;Kiriakos N. Kutulakos;S. Narasimhan;Aswin C. Sankaranarayanan
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文献类型：
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作者：
Chia-Yin Tsai;Kiriakos N. Kutulakos;S. Narasimhan;Aswin C. Sankaranarayanan
非视距(NLOS)成像利用完整的5D光瞬变测量来重建相机视野之外的场景。从数学上讲，这需要解决椭圆形层析成像问题，将形状和反照率从非视距场景的空间多路复用测量中分离出来。在本文中，我们提出了一种新的非视距成像方法，通过研究来自三跳光路的一次返回光子的性质。我们发现，首次返回的光子的飞行时间仅取决于非视距场景的几何形状，并且每次观测几乎总是从单个非视距场景点产生。利用这些性质，我们推导出了一种非视距场景的空间分割算法。此外，在假设局部平面性的基础上，提出了一种三维非视距场景点定位算法，并对其表面法线进行了估计。我们的方法既不需要全瞬变测量，也不需要解决硬椭圆层析成像问题。我们通过仿真和从SPAD传感器获取的真实数据来证明我们的方法的有效性。
Non-line-of-sight (NLOS) imaging utilizes the full 5D light transient measurements to reconstruct scenes beyond the cameras field of view. Mathematically, this requires solving an elliptical tomography problem that unmixes the shape and albedo from spatially-multiplexed measurements of the NLOS scene. In this paper, we propose a new approach for NLOS imaging by studying the properties of first-returning photons from three-bounce light paths. We show that the times of flight of first-returning photons are dependent only on the geometry of the NLOS scene and each observation is almost always generated from a single NLOS scene point. Exploiting these properties, we derive a space carving algorithm for NLOS scenes. In addition, by assuming local planarity, we derive an algorithm to localize NLOS scene points in 3D and estimate their surface normals. Our methods do not require either the full transient measurements or solving the hard elliptical tomography problem. We demonstrate the effectiveness of our methods through simulations as well as real data captured from a SPAD sensor.