Wallace W T, Lockhead G R
Department of Psychology, Duke University, Durham, NC 27706.
Vision Res. 1987;27(9):1589-601. doi: 10.1016/0042-6989(87)90167-2.
The perception of gradually changing luminance distributions was investigated. Luminance changed across the radius of a disk by a linear, quadratic, or cubic function with varying magnitudes. Subjects selected matching luminances for the inner and outer edges of each stimulus. The threshold for reporting that the inner and outer matches were different occurred at approximately 20% contrast between those regions. This threshold did not vary with the particular function which described the luminance distribution. Further, as the magnitude of luminance change across the stimulus increased, subjects judged the inner and outer edges to differ more in brightness. Matching luminances also depended upon the background configuration with greater differences perceived across the disk radius when the surround and center dot of the stimulus were of opposite, rather than the same, luminance. These results indicate that models of brightness must consider all luminance changes in the stimulus, not just changes of a particular type such as second differences or changes at a luminance step.
对逐渐变化的亮度分布的感知进行了研究。亮度通过线性、二次或三次函数在圆盘半径上以不同幅度变化。受试者为每个刺激的内边缘和外边缘选择匹配的亮度。报告内边缘和外边缘匹配不同的阈值出现在这些区域之间约20%的对比度处。该阈值不随描述亮度分布的特定函数而变化。此外，随着整个刺激中亮度变化幅度的增加，受试者判断内边缘和外边缘在亮度上的差异更大。匹配的亮度还取决于背景配置，当刺激的周围和中心点亮度相反而非相同时，在圆盘半径上感知到的差异更大。这些结果表明，亮度模型必须考虑刺激中的所有亮度变化，而不仅仅是特定类型的变化，如二阶差异或亮度阶跃处的变化。
