Visual, Spatial and Temporal Filtering and Hyperacuity

视觉、空间和时间过滤和超敏锐度

• 批准号: 8708606
• 负责人: Robert Shapley
• 金额: $ 26.33万
• 依托单位: New York University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-15 至 1991-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8708606&HistoricalAwards=false
• 关键词: Visual; Spatial; Temporal; Filtering; Hyperacuity

Visual acuity is a measure of how well the eye can resolve very tiny targets, and is limited by the size and distribution of the photoreceoptor cells in the eye. However, a slight sideways displacement break in an otherwise straight line can be detected when the displacement is as much as five times less than the normal acuity would predict. This discriminability is known as hyperacuity, and can be demonstrated by this stimulus called vernier displacement, or by displacement of a grating pattern or by bisection of a pattern. Understanding hyperacuity is important for understanding visual information processing because hyperacuity reveals the ultimate precision of visual localization in space. This project will study how spatial and temporal properties of information channels in the eye and brain determine the limits of hyperacuity. Single neurons (nerve cells) in the visual system have particular response properties that preferentially filter particular frequencies in time (cycles/sec) or space (cycles/degree, of a grating, for example). Hyperacuity targets or vernier and grating displacement will be presented to human observers, and then these targets will be "masked" by the presence of flickering illumination, or superimposed gratings, or spatiotemporal noise. The discriminations will be compared for these different cases. To determine the dynamic characteristics of the neural mechanisms involved will require measurement of displacement thresholds as a function of luminance contrast, color contrast, mean luminance, and temporal frequency. Finally, a comparison will be attempted between human hyperacuity performance and the hyperacute capabilities of single neurons in the macaque monkey's visual pathway. The goal of this work is a comprehensive understanding of the neural basis for hyperacuity. The approach combining psychophysics, physiology and mathematical modelling is rare and powerful. Understanding this wonderful performance in terms of neural mechanisms will lead to a better theoretical basis for understanding the ultimate limits of visual performance.

视觉敏锐度是衡量眼睛分辨非常微小目标的能力的指标，它受到眼睛中感光细胞的大小和分布的限制。然而，当位移比正常视力预测的小五倍时，可以检测到在其他直线上的轻微侧向位移中断。这种辨别能力被称为超敏度，可以通过这种被称为游标位移的刺激来证明，或者通过光栅图案的位移或通过图案的二等分来证明。了解超敏度对于理解视觉信息处理非常重要，因为超敏度揭示了视觉在空间定位的最终精确度。这个项目将研究眼睛和大脑中信息通道的空间和时间特性如何决定超敏度的极限。视觉系统中的单个神经元(神经细胞)具有特定的响应特性，优先在时间(周期/秒)或空间(例如，栅格的周期/度)上过滤特定频率。超锐度目标或游标和栅格的位移将呈现给人类观察者，然后这些目标将被闪烁的照明、叠加的栅格或时空噪声的存在所掩盖。将对这些不同的情况进行歧视比较。为了确定所涉及的神经机制的动态特性，需要测量作为亮度对比度、颜色对比度、平均亮度和时间频率的函数的位移阈值。最后，我们将尝试比较人类的超敏度表现和猕猴视觉通路中单个神经元的超敏锐能力。这项工作的目标是全面了解超敏的神经基础。将心理物理学、生理学和数学建模结合在一起的方法是罕见的，也是强大的。从神经机制的角度理解这种奇妙的表现，将为理解视觉表现的终极极限提供更好的理论基础。