Geisler Wilson S, Perry Jeffrey S, Najemnik Jiri
Center for Perceptual Systems and Department of Psychology, University of Texas at Austin, Austin, TX 78712, USA.
J Vis. 2006 Aug 3;6(9):858-73. doi: 10.1167/6.9.1.
Two of the factors limiting progress in understanding the mechanisms of visual search are the difficulty of controlling and manipulating the retinal stimulus when the eyes are free to move and the lack of an ideal observer theory for fixation selection during search. Recently, we developed a method to precisely control retinal stimulation with gaze-contingent displays (J. S. Perry & W. S. Geisler, 2002), and we derived a theory of optimal eye movements in visual search (J. Najemnik & W. S. Geisler, 2005). Here, we report a parametric study of visual search for sine-wave targets added to spatial noise backgrounds that have spectral characteristics similar to natural images (the amplitude spectrum of the noise falls inversely with spatial frequency). Search time, search accuracy, and eye fixations were measured as a function of target spatial frequency, 1/f noise contrast, and the resolution falloff of the display from the point of fixation. The results are systematic and similar for the two observers. We find that many aspects of search performance and eye movement pattern are similar to those of an ideal searcher that has the same falloff in resolution with retinal eccentricity as the human visual system.
限制视觉搜索机制理解进展的两个因素是，当眼睛自由移动时难以控制和操纵视网膜刺激，以及在搜索过程中缺乏用于注视选择的理想观察者理论。最近，我们开发了一种使用注视相关显示器精确控制视网膜刺激的方法（J. S. 佩里和W. S. 盖斯勒，2002年），并且我们推导了视觉搜索中最优眼动的理论（J. 纳杰姆尼克和W. S. 盖斯勒，2005年）。在此，我们报告一项对添加到具有与自然图像相似光谱特征（噪声的幅度谱随空间频率呈反比下降）的空间噪声背景中的正弦波目标进行视觉搜索的参数研究。测量了搜索时间、搜索准确性和眼注视情况，作为目标空间频率、1/f噪声对比度以及显示器从注视点起分辨率衰减的函数。两位观察者的结果具有系统性且相似。我们发现，搜索性能和眼动模式的许多方面与理想搜索者相似，该理想搜索者在分辨率随视网膜偏心率的衰减方面与人类视觉系统相同。
