Logvinenko Alexander D, Maloney Laurence T
Department of Vision Sciences, Glasgow Caledonian University, Glasgow G4 0BA, Scotland.
Percept Psychophys. 2006 Jan;68(1):76-83. doi: 10.3758/bf03193657.
In asymmetric lightness matching tasks, observers sometimes report that they cannot achieve satisfactory matches between achromatic surfaces under different neutral illuminants. The surfaces appear different, yet no further adjustment of either surface improves the match. There are evident difficulties in interpreting data from a task that the observer cannot always do, and these difficulties likely affect the interpretation of a large number of previous studies. We investigated, as an alternative to asymmetric matching, the direct use of proximity judgments in the study of surface lightness perception. We asked observers to rate the perceived dissimilarity of pairs of achromatic surfaces that were placed in identical scenes and viewed under different neutral illuminants. We develop a parametric model that accurately predicts perceived dissimilarity in terms of physical light intensities and surface albedos. The parameters of this model are readily interpretable. In particular, the ratio of the influence of changes in illuminant intensity and changes in surface albedo is a measure of the extent to which the observer discounts the illuminant. Asymmetric lightness matching can be interpreted as an unachievable limiting case of proximity judgment.
在非对称明度匹配任务中，观察者有时会报告说，他们无法在不同中性照明条件下的消色差表面之间实现令人满意的匹配。这些表面看起来不同，但对任何一个表面进行进一步调整都无法改善匹配效果。从观察者并不总能完成的任务中解读数据存在明显困难，而这些困难可能会影响对大量先前研究的解读。作为非对称匹配的替代方法，我们研究了在表面明度感知研究中直接使用接近度判断。我们要求观察者对放置在相同场景中并在不同中性照明条件下观察的消色差表面对的感知差异进行评分。我们开发了一个参数模型，该模型根据物理光强度和表面反照率准确预测感知差异。该模型的参数易于解释。特别是，照明强度变化和表面反照率变化的影响之比是观察者对照明折扣程度的一种度量。非对称明度匹配可以解释为接近度判断的一个无法实现的极限情况。
