Computational Psychology, Faculty of Electrical Engineering and Computer Science, Technische Universität Berlin, Berlin, Germany.
J Vis. 2022 Feb 1;22(2):2. doi: 10.1167/jov.22.2.2.
One fundamental question in vision research is how the retinal input is segmented into perceptually relevant variables. A striking example of this segmentation process is transparency perception, in which luminance information in one location contributes to two perceptual variables: the properties of the transparent medium itself and of what is being seen in the background. Previous work by Robilotto et al. (2002, 2004) suggested that perceived transparency is closely related to perceived contrast, but how these two relate to retinal luminance has not been established. Here we studied the relationship between perceived transparency, perceived contrast, and image luminance using maximum likelihood conjoint measurement (MLCM). Stimuli were rendered images of variegated checkerboards that were composed of multiple reflectances and partially covered by a transparent overlay. We systematically varied the transmittance and reflectance of the transparent medium and measured perceptual scales of perceived transparency. We also measured scales of perceived contrast using cut-outs of the transparency stimuli that did not contain any geometrical cues to transparency. Perceptual scales for perceived transparency and contrast followed a remarkably similar pattern across observers. We tested the empirically observed scales against predictions from various contrast metrics and found that perceived transparency and perceived contrast were equally well predicted by a metric based on the logarithm of Michelson or Whittle contrast. We conclude that judgments of perceived transparency and perceived contrast are likely to be supported by a common mechanism, which can be computationally captured as a logarithmic contrast.
视觉研究中的一个基本问题是视网膜输入如何被分割为感知相关的变量。透明度感知就是这种分割过程的一个显著例子，其中一个位置的亮度信息贡献于两个感知变量：透明介质本身的属性和背景中看到的东西的属性。Robilotto 等人的先前研究（2002 年，2004 年）表明，感知透明度与感知对比度密切相关，但这两个变量与视网膜亮度的关系尚未确定。在这里，我们使用最大似然联合测量（MLCM）研究了感知透明度、感知对比度和图像亮度之间的关系。刺激是由多个反射率组成的斑驳棋盘格的渲染图像，部分被透明覆盖物覆盖。我们系统地改变透明介质的透光率和反射率，并测量感知透明度的感知尺度。我们还使用不包含任何透明度几何提示的透明度刺激的切出来测量感知对比度的尺度。感知透明度和对比度的感知尺度在观察者之间呈现出非常相似的模式。我们根据各种对比度度量标准对经验观察到的尺度进行了测试，发现基于 Michelson 或 Whittle 对比度对数的度量标准可以很好地预测感知透明度和对比度。我们的结论是，感知透明度和感知对比度的判断可能由一个共同的机制支持，该机制可以被计算为对数对比度。
