Studies of Spatial and Temporal Integration of Differing Chromaticities by the Human Visual System

Switches Lay摘要（0116895）“Studies of Spatial and Temporal Integration of Differering Chromaticities”在正常视觉环境中，空间轮廓可以通过沿着多个刺激维度的变化来定义，例如亮度、色度、纹理、速度和深度。在过去的三十年中，早期视觉处理的研究已经表征和比较了人类视觉系统提取由这些变化定义的个体空间特征（线、边缘、光栅分量）的能力。视觉处理的后续步骤必须整合个体特征，以获得对形式的整体感知。这项拨款申请描述了一系列的心理物理学实验，研究涉及空间，时间和色彩信息的这种中级视觉处理的各个方面。特征的颜色或亮度对比度的相似性用作将对象分离成不同感知分组的重要基础;然而，照明和其他因素可以在构成单个对象的元素之间呈现亮度或颜色的变化。目前的建议认为，其元素是由亮度对比度或颜色对比度定义的图案，并研究人类视觉系统的能力，感知形式和运动时，集成不同的色度或亮度的元素特征。 除了分析中级时空处理中的特征整合外，本实验还将研究“第三阶段”色彩处理的机制。虽然许多现象涉及色觉可以合理化的受体激活（第一阶段）和视网膜/LGN对手的过程（第二阶段），电生理和心理物理学的研究都不清楚颜色信息在视觉皮层的进一步转换。在这个提议中的实验将测量我们检测个体特征之间的相关性的能力，这些相关性既作为它们的不同色度和它们的平均色度的函数。比较性能沿着各种彩色轴在三维颜色空间将分析在处理彩色信息的可能的第三阶段的机制。提出了三个一般性研究：i）由亮度或颜色变化定义的图案的对比度匹配的性质; ii）在各个元素的颜色/亮度对比度不同的情况下整合空间相关性的能力;以及iii）在色度不同的时域特征中整合的能力。第一组研究的目标是建立一个基本的度量的感知显着性的图案不同的颜色/亮度的实验涉及对比度匹配的正弦光栅。在第二组研究中，将利用点对元素内和点对元素之间具有亮度/色度变化的平移和旋转玻璃图案来研究将局部特征集成在全局图案的感知中的机制的“色盲”（或不）的程度。第三个领域包括实验探索两种类型的时间整合跨色度：视觉系统的能力，以融合两个时间上不一致的闪光下降沿着不同的色轴和它的能力，以检测运动的空间和时间位移的点，其色度是改变在时空位移。这三项研究是由视觉系统整合信息最初由不同的第二阶段色机制分离的问题？该提案解决了在了解大脑机制和视觉行为之间的联系方面具有根本重要性的问题。这项工作还与国际和平研究所在教育和外联方面的努力密切相关。与本提案的科学目标相关的技术、设备和结果将用于各种活动，如由美国国家科学基金会资助的自适应光学/宇宙中心课程“光子、蛋白质和感知”，该课程由PI于2001年组织;该课程旨在让来自代表性不足的高中生接触大学科学环境（http：//www.chemistry.ucsc.edu/COSVIS/）。

Switkes Lay Abstract (0116895)"Studies of Spatial and Temporal Integration of Differing Chromaticities" In the normal visual environment spatial contours may be defined by variations along a number of stimulus dimensions, e.g. luminance, chromaticity, texture, velocity, and depth. During the past three decades, studies of early visual processing have characterized and compared the ability of the human visual system to extract individual spatial features (lines, edges, grating components) defined by such variations. Subsequent steps of visual processing must integrate individual features to attain the global perception of form. This grant application describes a series of psychophysical experiments which investigate aspects of this mid-level visual processing involving spatial, temporal, and chromatic information. Similarities in the color or luminance contrast of features serve as an important basis for segregating objects into differing perceptual groupings; however, lighting and other factors can render variations in luminance or color among the elements comprising an individual object. The current proposal considers patterns whose elements are defined by luminance contrast or by color contrast and investigates the ability of the human visual system to perceive form and motion when integrating elemental features differing in chromaticity or luminance. In addition to analyzing integration of features in mid-level spatiotemporal processing, the proposed experiments will also investigate the mechanisms of 'third-stage' chromatic processing. While many phenomena involving color vision can be rationalized in terms of receptor activation (first-stage) and retinal/LGN opponent processes (second-stage), both electrophysiological and psychophysical studies are unclear regarding further transformations of color information in visual cortex. Experiments in this proposal will measure our ability detect correlations among individual features both as a function of their differing chromaticities and their average chromaticities. Comparative performance along various chromatic axes in three-dimensional color space will be analyzed in terms of possible third-stage mechanisms involved in processing chromatic information. Three general studies are proposed: i) the nature of contrast matching for patterns defined by luminance or color variations; ii) the ability to integrate spatial correlations where the individual elements differ in color/luminance contrast; and iii) the ability to integrate in the time domain features which differ in chromaticity. The goal of the first set of studies is to establish a basic metric for the perceived salience of patterns differing in color/luminance; the experiments involve contrast matching of sinusoidal gratings. In the second set of studies translational and rotational Glass patterns with luminance/chromaticity variations both within and among dot-pair elements will be utilized to investigate the degree of "color-blindness" (or not) of mechanisms which integrate the local features in the perception of global patterns. The third area includes experiments probing two types of temporal integration across chromaticities: the visual system's ability to fuse two temporally noncoincident flashes which fall along differing chromatic axes and its ability to detect motion from the spatial and temporal displacement of dots whose chromaticity is altered during the spatiotemporal displacement. The three studies are linked by the question can the visual system integrate information initially segregated by differing second-stage chromatic mechanisms? The proposal addresses questions of fundamental importance in gaining an understanding of the linkage between brain mechanisms and visual behavior. The work is also closely associated with the PI's efforts in education and outreach. Techniques, equipment, and results associated with the scientific goals of this proposal will be utilized in activities such as the NSF funded Center for Adaptive Optics/COSMOS course "Photons, Proteins, and Perception" which the PI has organized for 2001; a course aimed at allowing high school students from underrepresented demographics to be exposed to a university science environment (http://www.chemistry.ucsc.edu/COSVIS/).