Mechanisms of Color Detection, Induction and Adaptation

颜色视觉最重要的功能可能是识别物体和材料的光源，以及识别物体的光源。在色彩恒常性的文献中，几乎所有的实验工作和大多数计算模型都表明，神经系统应该对光源进行折扣，以便物体的颜色看起来是恒定的。然而，这个项目是基于对比观察，在许多情况下，物体在不同的光源下确实呈现出系统的不同颜色。当 当光源光谱改变时，反射光光谱的改变导致所有自然物体的锥体反射的类似倍增改变。使用真实的和模拟的刺激，我们会问观察者是否可以使用这些变化来识别物体和光源，使用外观的相似性或外观变化的比较。在跨发光体的识别依赖于比较对象中的颜色变化与背景中的颜色变化的情况下，我们将推导出所使用的几何颜色关系。我们将通过使用定理作为一致性检查来研究感知颜色空间的内在几何，并测试其对照明变化的不变性。世界上大多数物体的颜色都不均匀，因此我们将测试图案化的物体，看看局部对比度的识别是否有助于识别材料。当只有一个单一的发光体存在时，外观的恒定性是材料识别的最佳线索。我们将进行测试 恒常性机制在空间上延伸，或者在空间上是局部的但在时间上延伸，并且还测试结果是否需要适应模型或感知参考框架。我们将直接测量 光源的感知颜色，识别在此估计中使用的场景统计，并测试此估计是否用于颜色恒定性。该项目的结果将提供对日常色彩任务背后的神经计算和表示的见解。在这里开发的方法将是有用的，在确定功能性后果的色觉缺陷。

Possibly the most important functions of color vision are the identification of objects and materials across illuminants, and of illuminants across sets of objects. In the color constancy literature, almost all experimental work, and most computational models, suggest that the nervous system should discount the illuminant so that colors of objects appear constant. This project, however, is based on the contrasting observation that, in many situations, objects do appear to be of systematically different colors under different illuminants. When the illuminant spectrum changes, changes in the spectra of reflected lights result in similar multiplicative changes in cone absorptions for all natural objects. Using real and simulated stimuli, we will ask whether observers can use these shifts to identify objects and illuminants, using similarity of appearance or comparisons of shifts in appearance. Where identification across illuminants depends on comparing color changes in objects to color changes in backgrounds, we will derive the geometric color relations that are used. We will study the intrinsic geometry of perceptual color space by using theorems as consistency checks, and test its invariance to illuminant changes. Most objects in the world are not uniform in color, so we will test patterned objects to see whether identification of local contrasts helps in identifying materials. When only a single illuminant is present, constancy of appearance is the best cue for material identification. We will perform tests of whether constancy mechanisms extend over space or are spatially local but extend across time, and also test whether the results require models of adaptation or perceptual frames of reference. We will directly measure the perceived color of the illuminant, identify the scene statistics that are used in this estimation, and test if thisestimate is used in color constancy. The results of this project will provide insights into neural computations and representations underlying everyday color tasks. The methods developed here will be useful in identifying functional consequences of color vision deficits.