How attention and contrast gain control interact to regulate lightness contrast and assimilation: A computational neural model
How attention and contrast gain control interact to regulate lightness contrast and assimilation: A computational neural model
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DOI：
10.1167/10.14.40
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发表时间：
2010-01-01
影响因子：
1.8
通讯作者：
Rudd, Michael E.
中科院分区：
文献类型：
--
作者：
Rudd, Michael E.
最近的亮度感知理论认为，亮度(感知反射率)是通过将目标的亮度与其空间环境中的一个或多个区域的亮度进行对比的过程来计算的。对任何这类理论的挑战是亮度同化现象，当增加周围区域的亮度增加目标亮度时就会发生这种现象：与对比度相反。在利用同心圆盘和环形显示器的亮度匹配实验中，定量地研究了对比度和同化度。是否看到对比度或同化取决于许多因素，包括：目标、周围和背景的亮度关系；周围大小；以及匹配的指令。当同化发生时，它始终是一个更大的模式的一部分，在这个模式中，同化和对比都发生在不同范围的周围亮度上。这些发现是由一种理论定量模拟的，该理论假设亮度是通过视觉皮质中边缘探测神经元的反应的加权和来计算的。神经对边缘的响应的大小由相邻边缘检测器之间的对比度增益控制和自上而下的注意增益控制的组合来调节，该注意增益控制根据刺激边缘的任务相关性来选择性地加权对刺激边缘的响应。
Recent theories of lightness perception assume that lightness (perceived reflectance) is computed by a process that contrasts the target's luminance with that of one or more regions in its spatial surround. A challenge for any such theory is the phenomenon of lightness assimilation, which occurs when increasing the luminance of a surround region increases the target lightness: the opposite of contrast. Here contrast and assimilation are studied quantitatively in lightness matching experiments utilizing concentric disk-and-ring displays. Whether contrast or assimilation is seen depends on a number of factors including: the luminance relations of the target, surround, and background; surround size; and matching instructions. When assimilation occurs, it is always part of a larger pattern in which assimilation and contrast both occur over different ranges of surround luminance. These findings are quantitatively modeled by a theory that assumes lightness is computed from a weighted sum of responses of edge detector neurons in visual cortex. The magnitude of the neural response to an edge is regulated by a combination of contrast gain control acting between neighboring edge detectors and a top-down attentional gain control that selectively weights the response to stimulus edges according to their task relevance.