Spatial Layout and Image Scale in Low Vision

描述(申请人提供)：这项提案的长期目标是了解视力低下的人如何分析和处理图像和场景在多个尺度上的二维布局。拟议研究的主要主题是对低视力空间布局的感知，特别是对两个维度的布局的感知，例如，对放大或未放大的计算机屏幕的感知，或通过光学或视频距离望远镜对视觉场景的单目图像的感知。使用高度普遍的低视力、中央视野丧失(CFL)和正常视力的受试者，在正常视觉条件和模拟CFL条件下，将使用心理物理方法来解决两个主要问题： 全球布局感知：将以网页、自然城市场景和由基本形状组成的彩色图画三种(未放大)图像来衡量图像元素识别和元素定位的准确性。曝光时间也将有所不同，以评估从这种图像的一瞥可以预先注意保持空间布局的程度。 链接全局和局部视图：人们在尝试将全局视图中的对象链接到他们在放大图像视图中重新成像的对象时使用的策略将被检查，通过1)测量受试者在基于相对于那些任务的低于阈值的信息来评估执行焦点视觉任务所需的放大量时的准确性，通过2)评估学习基于反馈准确地评估放大需求的能力，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.