IEEE Trans Pattern Anal Mach Intell. 2017 Sep;39(9):1880-1891. doi: 10.1109/TPAMI.2016.2613862. Epub 2016 Sep 27.
Photometric stereo is widely used for 3D reconstruction. However, its use in scattering media such as water, biological tissue and fog has been limited until now, because of forward scattered light from both the source and object, as well as light scattered back from the medium (backscatter). Here we make three contributions to address the key modes of light propagation, under the common single scattering assumption for dilute media. First, we show through extensive simulations that single-scattered light from a source can be approximated by a point light source with a single direction. This alleviates the need to handle light source blur explicitly. Next, we model the blur due to scattering of light from the object. We measure the object point-spread function and introduce a simple deconvolution method. Finally, we show how imaging fluorescence emission where available, eliminates the backscatter component and increases the signal-to-noise ratio. Experimental results in a water tank, with different concentrations of scattering media added, show that deconvolution produces higher-quality 3D reconstructions than previous techniques, and that when combined with fluorescence, can produce results similar to that in clear water even for highly turbid media.
光度立体技术被广泛应用于三维重建。然而，由于来自光源和物体的前向散射光，以及从介质中向后散射的光（背向散射），其在水、生物组织和雾等散射介质中的应用一直受到限制。在本文中，我们在单散射假设适用于稀疏介质的情况下，对三种关键的光传播模式做出了贡献。首先，我们通过广泛的模拟表明，来自光源的单散射光可以用具有单一方向的点光源来近似，从而减轻了显式处理光源模糊的需要。其次，我们对来自物体的光散射引起的模糊进行建模。我们测量了物体点扩散函数并引入了一种简单的反卷积方法。最后，我们展示了如何在有荧光发射的情况下成像，消除背向散射分量并提高信噪比。在水箱中的实验结果表明，与先前的技术相比，反卷积可以产生更高质量的 3D 重建，并且当与荧光结合使用时，即使对于高度混浊的介质，也可以产生类似于清水的结果。
