Grouping local orientation and direction signals to extract spatial contours: Empirical tests of "association field" models of contour integration
Grouping local orientation and direction signals to extract spatial contours: Empirical tests of "association field" models of contour integration
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DOI：
10.1016/j.visres.2005.04.002
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发表时间：
2005-09-01
期刊：
影响因子：
1.8
通讯作者：
Geisler, WS
中科院分区：
文献类型：
--
作者：
Ledgeway, T;Hess, RF;Geisler, WS
在过去十年左右的时间里，大量的心理物理学研究试图描绘出局部取向和运动在空间中结合的原理，以便于检测简单的空间轮廓。这导致了轮廓检测的“关联场”模型的发展，该模型表明图像中相邻元素之间的链接强度由它们沿着平滑（一阶）曲线对齐的程度决定。为了测试这一假设，我们使用了一个路径检测范式来比较观察者的能力，以确定存在的轮廓定义的空间方向，运动方向或两种类型的视觉属性的特定组合。局部取向和/或方向相对于所描绘的轮廓的轴的相对对准被系统地改变。对于方向定义的轮廓检测，当元素沿着轮廓轴沿着（平行于）对齐时是最好的，对于倾斜方向的元素接近机会水平，然后对于与轮廓轴正交的元素（即，性能是取向未对准程度的U形函数）。这种模式的结果被发现为直和弯曲的轮廓，是不容易解释的，在目前的协会领域的理论。然而，对于运动定义的轮廓，由于组成路径元素的相对方向相对于轮廓逐渐失准，性能简单地恶化。因此，将局部方向连接起来以定义空间轮廓的规则与用于连接局部方向的规则在性质上是不同的，并且每个规则都可以由不同的视觉机制来调节。当方向和运动提示同时可用时，轮廓检测性能通常以与概率求和一致的方式增强。我们认为，关联领域模型的方向链接可能需要根据目前的研究结果进行扩展。(c)2005爱思唯尔有限公司保留所有权利。
Over the last decade or so a great deal of psychophysical research has attempted to delineate the principles by which local orientations and motions are combined across space to facilitate the detection of simple spatial contours. This has led to the development of "association field" models of contour detection which suggest that the strength of linking between neighbouring elements in an image, is determined by the degree to which they aligned along smooth (first-order) curves. To test this assumption we used a path detection paradigm to compare the ability of observers to identify the presence of contours defined by either spatial orientation, motion direction or by specific combinations of both types of visual attribute. The relative alignment of the local orientations and/or directions with respect to the axis of the depicted contour was systematically varied. For orientation-defined contours detection was best when the elements were aligned along (parallel with) the contour axis, approached chance levels for obliquely oriented elements and then improved for elements that were orthogonal to the contour axis (i.e., performance was a U-shaped function of degree of orientation misalignment). This pattern of results was found for both straight and curved contours and is not readily explicable in terms of current association field theories. For motion-defined contours, however, performance simply deteriorated as the relative directions of the constituent path elements were progressively misaligned with respect to the contour. Thus the rules by which local orientations are linked to define spatial contours are qualitatively different from those used for linking local directions and each may be mediated by distinct visual mechanisms. When both orientation and motion cues were simultaneously available, contour detection performance was generally enhanced, in a manner that is consistent with probability summation. We suggest that association field models of orientation linking may need to be extended in light of the present findings. (c) 2005 Elsevier Ltd. All rights reserved.