Specular reflections and the perception of shape
Specular reflections and the perception of shape
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DOI：
10.1167/4.9.10
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发表时间：
2004-01-01
影响因子：
1.8
通讯作者：
Adelson, EH
中科院分区：
文献类型：
--
作者：
Fleming, RW;Torralba, A;Adelson, EH
许多材质（包括树叶、水、塑料和Chrome）都会显示镜面反射。这似乎是合理的，视觉系统可以以某种方式利用镜面反射恢复三维（3D）形状。既往研究（例如：J. T.托德& E. Mingolla，1983; J. F.诺曼，J. T。托德，& G. A. Orban，2004）已经表明镜面反射有助于形状估计，但是相关的图像信息尚未被隔离。在这里，我们解释了镜面反射如何提供可靠和准确的3D形状约束。我们认为，视觉系统可以处理镜面有点像纹理，通过使用系统的模式，整个图像的镜面反射表面的失真恢复3D形状。然而，纹理和镜面反射之间有一个关键的区别：在纹理的情况下，图像压缩取决于表面深度的一阶导数（即，表面取向），而在镜面反射的情况下，图像压缩取决于二阶导数（即，曲面曲率）。我们认为，这种差异提供了一个线索，可以帮助视觉系统区分纹理和镜面反射，即使同时存在。更重要的是，我们表明，镜面反射扭曲的依赖表面的二阶导数导致独特的领域的图像方向的反射的世界是扭曲的表面。我们发现，这些“方向场”是（i）诊断的3D形状，（ii）保持令人惊讶的稳定时，反映在表面上的世界发生变化，（iii）可以从图像中提取的人口简单的定向过滤器。因此，使用镜面反射的3D形状感知是更容易和更可靠的比以前的计算工作将建议。
Many materials, including leaves, water, plastic, and chrome exhibit specular reflections. It seems reasonable that the visual system can somehow exploit specular reflections to recover three-dimensional (3D) shape. Previous studies (e.g., J. T. Todd & E. Mingolla, 1983; J. F. Norman, J. T. Todd, & G. A. Orban, 2004) have shown that specular reflections aid shape estimation, but the relevant image information has not yet been isolated. Here we explain how specular reflections can provide reliable and accurate constraints on 3D shape. We argue that the visual system can treat specularities somewhat like textures, by using the systematic patterns of distortion across the image of a specular surface to recover 3D shape. However, there is a crucial difference between textures and specularities: In the case of textures, the image compressions depend on the first derivative of the surface depth (i.e., surface orientation), whereas in the case of specularities, the image compressions depend on the second derivative (i.e., surfaces curvatures). We suggest that this difference provides a cue that can help the visual system distinguish between textures and specularities, even when present simultaneously. More importantly, we show that the dependency of specular distortions on the second derivative of the surface leads to distinctive fields of image orientation as the reflected world is warped across the surface. We find that these "orientation fields" are (i) diagnostic of 3D shape, (ii) remain surprisingly stable when the world reflected in the surface is changed, and (iii) can be extracted from the image by populations of simple oriented filters. Thus the use of specular reflections for 3D shape perception is both easier and more reliable than previous computational work would suggest.