Contour detection threshold: repeatability and learning with 'contour cards'
Contour detection threshold: repeatability and learning with 'contour cards'
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DOI：
10.1163/156856899x00157
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发表时间：
1999-01-01
期刊：
影响因子：
--
通讯作者：
Norcia, AM
中科院分区：
文献类型：
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作者：
Pennefather, PM;Chandna, A;Norcia, AM
人类观察者能够定位仅基于长距离方向域相关性定义的轮廓。负责二阶轮廓检测的机制的完整性被弱视破坏（Kovacs等人，1996年; Hess等人，1997），并且因此开发用于评估经历弱视治疗的儿科患者的方法是令人感兴趣的。在这项研究中，我们已经确定了观察员间和重测信度的二阶轮廓积分卡为基础的测试。还在成人和儿科患者组中评估了实践效果的大小。轮廓检测阈值测量的封闭轮廓，定义的Gabor补丁，嵌入在一个随机定向的Gabor补丁背景。通过改变背景元素的密度来控制轮廓的可见性。轮廓元素间距与平均背景间距之比定义的轮廓间距用临床阶梯程序测量。由两个观察者测量的两张牌之间的平均差异为0.023 +/-0.075或约为两张牌之间增量的一半。儿童和成人仅表现出很小的练习效果（分别为0.022 +/-0.051 vs 0.053 +/-0.077），重复测量之间的平均无符号差异相当于各组之间的约1张卡片。基于卡片的二阶轮廓整合测试产生了正常和弱视观察者（包括儿童）轮廓整合性能的可靠估计。
Human observers are able to locate contours that are defined solely on the basis of long-range, orientation-domain correlations. The integrity of the mechanisms responsible for second-order contour detection is disrupted by amblyopia (Kovacs et nl., 1996; Hess et al., 1997) and it is therefore of interest to develop methods for assessing pediatric patients undergoing treatment for amblyopia. In this study, we have determined the inter-observer and test-retest reliability of a card-based test of second-order contour integration. The magnitude of practice effects was also assessed in both adult and pediatric patient groups. Contour detection thresholds were measured for a closed contour, defined by Gabor patches, embedded in a randomly oriented Gabor-patch background. The visibility of the contour was controlled by varying the density of the background elements. Thresholds, defined in terms of the ratio of contour element spacing to average background spacing were measured with a clinical staircase procedure. Thresholds measured by two observers differed on average by 0.023 +/- 0.075 or about one half the increment between cards. Children and adults showed only small practice effects (0.022 +/- 0.051 vs 0.053 +/- 0.077, respectively) and average unsigned differences between repeated measures were equivalent to approximately 1 card across groups. A card-based test of second-order contour integration produces reliable estimates of contour integration performance in normal and amblyopic observers, including children.