Jeffrey Brett G, Wang Yi Zhong, Birch Eileen E
Retina Foundation of the Southwest, 9900 North Central Expressway, Suite 400, Dallas, TX 75231, USA.
Vision Res. 2002 Nov;42(25):2773-9. doi: 10.1016/s0042-6989(02)00332-2.
Circular contour frequency (the number of radial cycles per degree of unmodulated contour length measured in degrees of viewing angle) is an important factor in determining the deformation threshold of radial frequency (RF) patterns. Radial deformation thresholds were closely matched at a given circular contour frequency regardless of RF or radius. Our results suggest that two separate mechanisms may be involved in determining radial deformation thresholds. First, for low RFs, our results support a model of shape discrimination in which global integration occurs across all modulation cycles of an RF pattern. Second, for higher RFs, our data suggest that threshold may be determined by visual integration only over a limited segment of the RF pattern.
圆形轮廓频率（每度未调制轮廓长度的径向周期数，以视角度数测量）是确定径向频率（RF）图案变形阈值的一个重要因素。在给定的圆形轮廓频率下，无论RF或半径如何，径向变形阈值都紧密匹配。我们的结果表明，可能有两种不同的机制参与确定径向变形阈值。首先，对于低RFs，我们的结果支持一种形状辨别模型，其中在RF图案的所有调制周期上进行全局整合。其次，对于较高的RFs，我们的数据表明阈值可能仅由RF图案有限部分上的视觉整合来确定。
