FLICKER-AUGMENTED CONTRAST--A NEW VISUAL EFFECT

闪烁增强对比度——新的视觉效果

• 批准号: 2163971
• 负责人: STUART ANSTIS
• 金额: $ 9.15万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2163971
• 关键词: brightness discrimination; human subject; light intensity; neural information processing; photostimulus; sequential perception; vision tests; visual perception

A steady gray test spot looks light gray on a dark surround and dark gray on a light surround, owing to simultaneous brightness induction, perhaps based on lateral inhibition. But a test spot of the same time-averaged luminance that flickers between black and white at 15 Hz looks almost white on a dark surround and almost black on a light surround. The flickering test spot changes its brightness by five to eight times as much as the gray spot. We call this newly discovered phenomenon flicker-augmented contrast (FAC). FAC is found in all the classic demonstrations of simultaneous contrast--Heinemann's disks, McCourt's induced gratings, White's effect, Koffka's rings and Benary's cross. We shall measure FAC as a function of surround luminance, retinal eccentricity, temporal frequency, and amplitude of the test flicker. Our experiments will test between various models of FAC, based on the idea that the light and dark phases of the flickering test disk each undergo separate brightness induction from the surround before being combined by the visual system. Two models of this combination are considered: linear summation of brightness, and nonlinear "winner-take-all" competitive combination. We propose that spatial increments and decrements are handled by separate Bright and Dark channels, possibly mediated by on- and off-center ganglion cells. These bright and dark signals are then combined in push-pull mode by an opponent output stage. The advantage of this opponent system is that it effectively doubles the limited intrinsic dynamic range of the neural pathways that signal luminance.

稳定的灰色测试点在深色周围和深色上看起来浅灰色 由于同时亮度诱导，在光线周围灰色， 也许基于横向抑制。 但是一个相同的测试点 在15 Hz的黑色和白色之间闪烁的时间平均亮度 在黑暗的环境上看起来几乎是白色的，几乎是黑色的。 环绕。 闪烁的测试点会将其亮度变为五个 是灰色斑点的八倍。 我们称这个新发现 现象闪烁的对比度（FAC）。 在所有中都发现了FAC 同时对比的经典演示 - 海因曼的磁盘， 麦考特的诱发光栅，怀特的效果，科夫卡的戒指和贝里的 叉。 我们将测量FAC作为周围亮度，视网膜的函数 测试闪烁的偏心率，时间频率和振幅。 我们的实验将根据fac的各种模型进行测试 闪烁测试磁盘的光和黑暗阶段的想法 在存在之前，请与周围的亮度诱导 由视觉系统组合。 这种组合的两种模型是 考虑：亮度和非线性的线性总和 “赢家全能”的竞争组合。 我们提出了这个空间 增量和减少由单独的明亮和黑暗来处理 通道，可能是由内和中心神经节细胞介导的。 然后将这些明亮和黑暗的信号通过推扣模式组合 对手输出阶段。 这个对手系统的优势是 它有效地翻了一番 信号亮度的神经途径。