Visual discomfort from flicker: Effects of mean light level and contrast
Visual discomfort from flicker: Effects of mean light level and contrast
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DOI：
10.1016/j.visres.2020.05.002
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发表时间：
2020-08-01
期刊：
影响因子：
1.8
通讯作者：
Webster，Michael A.
中科院分区：
文献类型：
--
作者：
Yoshimoto，Sanae;Jiang，Fang;Webster，Michael A.
不舒适的图像通常具有特定的空间结构，其偏离傅立叶域（1/f）中的幅度和空间频率（f）之间的倒数关系。虽然具有类似时间结构的闪烁模式也出现不舒服，但不舒服不仅受到幅度谱的影响，而且还受到相位谱的影响。在这里，我们研究了如何从闪烁与不同的时间配置文件的不适也不同的平均光水平和亮度对比度的刺激的函数。要求参与者在从暗适应到明适应的不同光水平下对17°闪烁均匀场的不适进行评级。闪烁波形以方波或随机相位谱变化，并通过调制幅度谱相对于1/f的斜率进行滤波。在明视水平，1/f方波闪烁出现最舒适，而从随机闪烁的不适单调增加的幅度谱的斜率降低。1/f方波条件的这种特殊状态仅限于明视光水平。在较低的中间视觉或暗视觉水平下，相位谱对不适的影响减弱，两个相位谱均随振幅谱的斜率单调变化。我们表明，这些变化不能占的变化，有效的亮度对比度的刺激或响应的线性模型的基础上的时间脉冲响应在不同的光水平下。然而，从闪烁的不适是鲁棒相关的判断不同的对比度和平均亮度水平的闪烁的感知自然。
Uncomfortable images generally have a particular spatial structure, which deviates from a reciprocal relationship between amplitude and spatial frequency (f) in the Fourier domain (1/f). Although flickering patterns with similar temporal structure also appear uncomfortable, the discomfort is affected by not only the amplitude spectrum but also the phase spectrum. Here we examined how discomfort from flicker with differing temporal profiles also varies as a function of the mean light level and luminance contrast of the stimulus. Participants were asked to rate discomfort for a 17° flickering uniform field at different light levels from scotopic to photopic. The flicker waveform was varied with a square wave or random phase spectrum and filtered by modulating the slope of the amplitude spectrum relative to 1/f. At photopic levels, the 1/fsquare wave flicker appeared most comfortable, whereas the discomfort from the random flicker increased monotonically as the slope of the amplitude spectrum decreased. This special status for the 1/fsquare wave condition was limited to photopic light levels. At the lower mesopic or scotopic levels, the effect of phase spectrum on the discomfort was diminished, with both phase spectra showing a monotonic change with the slope of the amplitude spectrum. We show that these changes cannot be accounted for by changes in the effective luminance contrast of the stimuli or by the responses from a linear model based on the temporal impulse responses under different light levels. However, discomfort from flicker is robustly correlated with judgments of the perceived naturalness of flicker across different contrasts and mean luminance levels.