Scene content selected by active vision
Scene content selected by active vision
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DOI：
10.1163/15685680360511645
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发表时间：
2003-01-01
期刊：
影响因子：
--
通讯作者：
Niebur, E
中科院分区：
文献类型：
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作者：
Parkhurst, DJ;Niebur, E
灵长类动物的视觉系统通过视觉注意和眼球跳动机制，积极地从环境中选择视觉信息进行详细加工。本研究考察了由主动视觉选择的场景内容的统计特性。当参与者自由观看自然和人工场景的数字化图像时，记录了他们的眼球运动。确定每张图像的固定位置，并在观察到的固定位置周围提取图像补丁。在提取的图像斑块上计算局部对比度、局部空间相关性和空间频率含量。重复先前的结果，与在随机位置提取图像斑块的对比度或使用图像洗牌数据库观察到的固定位置的对比度相比，发现固定点的局部对比度更大。与一些结果相反，与文献中的其他结果一致，在固定位置和其他邻近位置之间观察到图像强度的显着去相关。讨论和分析了方法技术，为结果的差异提供了解释。我们的分析结果表明，固定点的局部对比度和相关性都是图像类型的函数，而且，这些影响的大小取决于图像中整体存在的对比度和相关性的水平。最后，在大约1度视角的距离上，局部对比和相关性的效应最大，这与视觉周边的最佳空间尺度选择性测量结果很好地吻合，视觉周边是对潜在扫视目标的视觉信息进行处理的地方。
The primate visual system actively selects visual information from the environment for detailed processing through mechanisms of visual attention and saccadic eye movements. This study examines the statistical properties of the scene content selected by active vision. Eye movements were recorded while participants free-viewed digitized images of natural and artificial scenes. Fixation locations were determined for each image and image patches were extracted around the observed fixation locations. Measures of local contrast, local spatial correlation and spatial frequency content were calculated on the extracted image patches. Replicating previous results, local contrast was found to be greater at the points of fixation when compared to either the contrast for image patches extracted at random locations or at the observed fixation locations using an image-shuffled database. Contrary to some results and in agreement with other results in the literature, a significant decorrelation of image intensity is observed between the locations of fixation and other neighboring locations. A discussion and analysis of methodological techniques is given that provides an explanation for the discrepancy in results. The results of our analyses indicate that both the local contrast and correlation at the points of fixation are a function of image type and, furthermore, that the magnitude of these effects depend on the levels of contrast and correlation present overall in the images. Finally, the largest effect sizes in local contrast and correlation are found at distances of approximately 1 deg of visual angle, which agrees well with measures of optimal spatial scale selectivity in the visual periphery where visual information for potential saccade targets is processed.