Optimal eye movement strategies in visual search
Optimal eye movement strategies in visual search
复制标题
DOI：
10.1038/nature03390
复制
发表时间：
2005-03-17
期刊：
影响因子：
64.8
通讯作者：
Geisler, WS
中科院分区：
文献类型：
--
作者：
Najemnik, J;Geisler, WS
为了进行视觉搜索，人类像许多哺乳动物一样，用具有不同空间分辨率的视网膜编码大范围的视野，然后使用高速眼球运动将分辨率最高的区域中心凹引导到潜在的目标位置(1，2)。良好的搜索性能对生存至关重要，因此哺乳动物可能已经进化出选择注视位置的有效策略。这里我们讨论两个问题：对于在杂乱的环境中寻找目标的凹陷视觉系统来说，什么是最优的眼动策略，以及人类在搜索过程中是否采用了最优的眼动策略？我们推导了搜索任务的理想贝叶斯观测器(3-6)，其中目标被嵌入在具有自然场景光谱特征的随机背景中的未知位置(7)。我们理想的搜索者使用关于目标所在场景的统计数据的精确知识，以及关于其自身视觉系统的精确知识，来进行眼睛运动，从而获得关于目标位置的最多信息。我们发现，人类获得了近乎最佳的搜索性能，尽管人类跨注视整合信息的能力很差(8-10)。对理想搜索者的分析表明，在不同的注视之间完美整合几乎没有什么好处--更重要的是对每个注视的信息进行有效的处理。显然，进化利用了这一事实，以最少的神经资源用于记忆，实现了高效的眼动策略。
To performvisual search, humans, like many mammals, encode a large field of view with retinas having variable spatial resolution, and then use high-speed eye movements to direct the highest-resolution region, the fovea, towards potential target locations(1,2). Good search performance is essential for survival, and hence mammals may have evolved efficient strategies for selecting fixation locations. Here we address two questions: what are the optimal eye movement strategies for a foveated visual system faced with the problem of finding a target in a cluttered environment, and do humans employ optimal eye movement strategies during a search? We derive the ideal bayesian observer(3-6) for search tasks in which a target is embedded at an unknown location within a random background that has the spectral characteristics of natural scenes(7). Our ideal searcher uses precise knowledge about the statistics of the scenes in which the target is embedded, and about its own visual system, to make eye movements that gain the most information about target location. We find that humans achieve nearly optimal search performance, even though humans integrate information poorly across fixations(8-10). Analysis of the ideal searcher reveals that there is little benefit from perfect integration across fixations - much more important is efficient processing of information on each fixation. Apparently, evolution has exploited this fact to achieve efficient eye movement strategies with minimal neural resources devoted to memory.