Walkey H C, Harlow J A, Barbur J L
Applied Vision Research Centre, Henry Wellcome Laboratories for Vision Sciences, City University, Northampton Square, London EC1V 0HB, UK.
Ophthalmic Physiol Opt. 2006 May;26(3):288-99. doi: 10.1111/j.1475-1313.2006.00412.x.
Vision relies on both rod and cone signals over a large range of ambient illumination that encompasses a number of common situations. It is important, therefore, to understand how performance changes with light level in functional visual tasks. We measured reaction times and search times using achromatic targets to examine the relationship between latency and luminance contrast as a function of background luminance. Visual search was more robust to changes in luminance than reaction time; search performance could be made invariant by scaling the effects of contrast, but the range of reaction time changed significantly over the mesopic range. We also investigated the extent to which two mesopic visual performance models described the dependence of reaction time and search time on stimulus spectra, using coloured stimuli. The 'effective contrast' model that we examined described the spectral dependence of both reaction time and search time well. A model for mesopic luminous efficiency based on reaction times described the spectral dependence of each response only in conditions where there was little influence of chromatic signals.
在涵盖多种常见情况的大范围环境光照下，视觉依赖于视杆细胞和视锥细胞的信号。因此，了解功能性视觉任务中性能如何随光照水平变化很重要。我们使用消色差目标测量反应时间和搜索时间，以研究潜伏期与亮度对比度之间随背景亮度变化的关系。视觉搜索对亮度变化的鲁棒性比反应时间更强；通过缩放对比度的影响可使搜索性能保持不变，但反应时间范围在中间视觉范围内变化显著。我们还使用彩色刺激研究了两种中间视觉性能模型在多大程度上描述了反应时间和搜索时间对刺激光谱的依赖性。我们研究的“有效对比度”模型很好地描述了反应时间和搜索时间的光谱依赖性。基于反应时间建立的中间视觉发光效率模型仅在色信号影响较小的条件下描述了每种反应的光谱依赖性。
