Image statistics and the perception of surface qualities
Image statistics and the perception of surface qualities
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DOI：
10.1038/nature05724
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发表时间：
2007-05-10
期刊：
影响因子：
64.8
通讯作者：
Adelson, Edward H.
中科院分区：
文献类型：
--
作者：
Motoyoshi, Isamu;Nishida, Shin'ya;Adelson, Edward H.
世界充满了表面，通过观察它们，我们可以判断它们的物质质量。颜色或光泽度等特性可以帮助我们判断煎饼是否煮熟，或者一块路面是否结冰。大多数表面外观的研究都强调无纹理的哑光表面（1-3），但现实世界的表面，可能具有光泽和复杂的介观结构，现在受到越来越多的关注（4-7）。它们的外观是由照明、反射率和表面几何形状复杂的相互作用造成的，这些因素很难从图像中分离出来。如果有简单的图像统计可以诊断表面属性，那么使用它们将是明智的（8-11）。本文表明，亮度直方图的偏度和子带滤波器输出的偏度与表面光泽度相关，与表面反照率（漫反射）负相关。我们发现有证据表明，人类观察者在判断表面时使用偏度，或类似的直方图不对称度量。当一个表面的图像具有正偏斜的统计量时，它往往比具有较低偏度的类似表面看起来更暗、更光滑，无论偏度是原始图像固有的还是由数字处理引入的，都是如此。我们还发现了基于偏度的视觉后效：对统计数据偏态的模式的适应可以改变随后观看的表面的表观亮度和光泽度。我们认为存在对偏斜统计敏感的神经机制，并且它们的输出可用于估计表面性质。
The world is full of surfaces, and by looking at them we can judge their material qualities. Properties such as colour or glossiness can help us decide whether a pancake is cooked, or a patch of pavement is icy. Most studies of surface appearance have emphasized textureless matte surfaces(1-3), but real-world surfaces, which may have gloss and complex mesostructure, are now receiving increased attention(4-7). Their appearance results from a complex interplay of illumination, reflectance and surface geometry, which are difficult to tease apart given an image. If there were simple image statistics that were diagnostic of surface properties it would be sensible to use them(8-11). Here we show that the skewness of the luminance histogram and the skewness of sub-band filter outputs are correlated with surface gloss and inversely correlated with surface albedo ( diffuse reflectance). We find evidence that human observers use skewness, or a similar measure of histogram asymmetry, in making judgements about surfaces. When the image of a surface has positively skewed statistics, it tends to appear darker and glossier than a similar surface with lower skewness, and this is true whether the skewness is inherent to the original image or is introduced by digital manipulation. We also find a visual aftereffect based on skewness: adaptation to patterns with skewed statistics can alter the apparent lightness and glossiness of surfaces that are subsequently viewed. We suggest that there are neural mechanisms sensitive to skewed statistics, and that their outputs can be used in estimating surface properties.