Mäkelä P, Whitaker D, Rovamo J
Department of Vision Sciences, Aston University, Aston Triangle, Birmingham, England.
Vision Res. 1993 Mar-Apr;33(5-6):723-30. doi: 10.1016/0042-6989(93)90192-y.
In many visual tasks thresholds can be made equal across the visual field by increasing the size of peripherally presented stimuli by appropriate magnification. The parameter E2 represents the eccentricity at which foveal stimulus size must double in order to maintain performance equivalent to that at the fovea. We measured orientation discrimination for a set of line sizes at various eccentricities. Thresholds were successfully scaled by applying a scaling function estimated by a technique that requires no prior assumptions regarding the size of peripherally presented stimuli. E2 of 1.95 deg was found for orientation discrimination. From our results we were able to develop a single equation which predicts orientation discrimination thresholds for an average observer over a range of different eccentricities and line lengths.
在许多视觉任务中，通过适当放大周边呈现刺激的大小，可以使整个视野的阈值相等。参数E2表示中央凹刺激大小必须加倍才能保持与中央凹处相当性能的离心率。我们测量了不同离心率下一组线条大小的方向辨别能力。通过应用一种无需对周边呈现刺激大小作先验假设的技术估计的缩放函数，成功地对阈值进行了缩放。发现方向辨别的E2为1.95度。根据我们的结果，我们能够推导出一个单一方程，该方程可预测普通观察者在一系列不同离心率和线条长度范围内的方向辨别阈值。
