J Opt Soc Am A Opt Image Sci Vis. 2021 Feb 1;38(2):203-210. doi: 10.1364/JOSAA.409454.
While much attention has been given to understanding biases in gloss perception (e.g., changes in perceived reflectance as a function of lighting, shape, viewpoint, and other factors), here we investigated sensitivity to changes in surface reflectance. We tested how visual sensitivity to differences in specular reflectance varies as a function of the magnitude of specular reflectance. Stimuli consisted of renderings of glossy objects under natural illumination. Using maximum likelihood difference scaling (MLDS), we created a perceptual scaling of the specular reflectance parameter of the Ward reflectance model. Then, using the method of constant stimuli and a standard 2AFC procedure, we obtained psychometric functions for gloss discrimination across a range of reflectance values derived from the perceptual scale. Both methods demonstrate that discriminability is significantly diminished at high levels of specular reflectance, thus indicating that gloss sensitivity depends on the magnitude of change in the image produced by different reflectance values. Taken together, these experiments also suggest that internal sensory noise remains constant for suprathreshold and near-threshold intervals of specular reflectance, which supports the use of MLDS as a highly efficient method for evaluating gloss sensitivity.
虽然人们已经关注了对光泽感知偏差的理解（例如，由于照明、形状、视角和其他因素的变化而导致的感知反射率的变化），但在这里我们研究了对表面反射率变化的敏感性。我们测试了视觉对镜面反射率差异的敏感性如何随镜面反射率的大小而变化。刺激物由自然光照下的有光泽物体的渲染组成。使用最大似然差标度（MLDS），我们创建了 Ward 反射模型的镜面反射率参数的感知标度。然后，使用恒定刺激法和标准的 2AFC 程序，我们从感知尺度中获得了不同反射率值的光泽判别心理物理函数。这两种方法都表明，在镜面反射率较高的水平上，可辨别性显著降低，这表明光泽敏感性取决于不同反射率值产生的图像中变化的大小。总之，这些实验还表明，内部感觉噪声在镜面反射率的超阈值和近阈值区间保持不变，这支持了 MLDS 作为评估光泽敏感性的高效方法的使用。
