Anderson R S, Thibos L N
Visual Sciences Group, School of Optometry, Indiana University, Bloomington 47405, USA.
J Opt Soc Am A Opt Image Sci Vis. 1999 Oct;16(10):2334-42. doi: 10.1364/josaa.16.002334.
We develop and test two functional hypotheses based on the sampling theory of visual resolution that might account for letter acuity in peripheral vision. First, a letter smaller than the acuity limit provides insufficient veridical energy for performing the task, and, second, the available veridical energy is masked by increased amounts of visible but aliased energy. These two hypotheses make opposite predictions about the effect of low-pass filtering on letter acuity, which we tested experimentally by using filtered letters from the tumbling-E alphabet. Our results reject the masking hypothesis in favor of the energy insufficiency hypothesis. Additional experiments in which high-pass-filtered letters were used permitted the isolation of a critical band of spatial frequencies, which is necessary and sufficient for achieving maximum visual acuity. This critical band varied with the particular pair of letters to be discriminated but was in the range 0.9-2.2 cycles per letter.
我们基于视觉分辨率的采样理论提出并测试了两个功能假设，这两个假设可能解释周边视觉中的字母视敏度。第一，小于视敏度极限的字母提供的真实能量不足以完成任务；第二，可用的真实能量被增加的可见但混叠的能量所掩盖。这两个假设对低通滤波对字母视敏度的影响做出了相反的预测，我们通过使用来自翻转E字母表的滤波字母进行了实验测试。我们的结果拒绝了掩蔽假设，支持能量不足假设。使用高通滤波字母的额外实验允许分离出一个关键的空间频率带，这对于实现最大视敏度是必要且充分的。这个关键带随要区分的特定字母对而变化，但在每个字母0.9 - 2.2周期的范围内。
