Spatial Layout and Image Scale in Low Vision

描述（由申请人提供）：该提案的长期目标是了解低视力人群如何在多个尺度上分析和处理图像和场景的二维布局。建议的研究的首要主题是感知低视力的空间布局，特别是在两个维度上的布局，例如，感知放大或未放大的计算机屏幕，或通过光学或视频距离望远镜辅助的视觉场景的单眼图像。使用具有高度普遍形式的低视力、中央视野丧失（CFL）的受试者以及在正常观看条件和模拟CFL下视力正常的受试者，将使用心理物理学方法解决两个主要问题： 全球布局感知：图像元素识别和元素定位的准确性将被测量三种（未放大）图像：网页，自然城市场景和基本形状组成的彩色图画。曝光持续时间也将变化，以评估空间布局可以从这些图像的一瞥中预先注意地保留的程度。 将全球和地方观点联系起来：人们在试图将全局视图中的对象链接到他们在放大图像视图内重新成像的对象时所使用的策略将通过以下方式来检查：1）测量受试者在基于相对于那些任务为亚阈值的信息来评估执行聚焦视觉任务所需的放大量时的准确度，通过2）评估学习能力以基于反馈准确地评估放大需要，以及通过3）评估受试者基于来自放大视图的反馈来测量指向误差的方向和大小的能力，作为放大的函数。

DESCRIPTION (provided by applicant): This proposal has the long-term goal of understanding how people with low vision analyze and process two-dimensional layout of images and scenes at multiple scales. The overarching theme of the proposed studies is perception of spatial layout in low vision, particularly on layout in two dimensions such as, for example, perception of a magnified or unmagnified computer screen, or of a monocular image of a visual scene through an optical or video distance telescopic aid. Using subjects with a highly prevalent form of low vision, central visual field loss (CFL), and normally-sighted subjects under both normal viewing conditions and simulated CFL, two main issues will be addressed using psychophysical methods: Global layout perception: Image element identification and accuracy of element localization will be measured with three kinds of (unmagnified) images: web pages, natural urban scenes and colored drawings composed of basic shapes. Exposure duration will also be varied in order to assess the degree to which spatial layout can be retained pre-attentively from glimpses of such images. Linking global and local views: The strategies people use in attempting to link objects in global view to objects they re-image within a magnified image view will be examined, by 1) measuring subjects' accuracy in assessing the amount of magnification required to perform focal visual tasks based on information that is sub threshold with respect to those tasks, by 2) assessing ability to learn to assess magnification needs accurately based on feedback, and by 3) assessing subjects' abilities to gauge direction and size of pointing errors based on feedback from a magnified view, as a function of magnification.