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level 14
这个论文里主要讨论的是闪烁百分比和频率。
频率的重要性没什么好说的，但闪烁百分比这个指标感觉不够。
percent flicker，闪烁百分比，modulation depth，调制深度，(max-min)/(max+min)*100%，完全没考虑形状。规则的图形，比如方波，其形状主要受占空比影响。不规则的更麻烦一些。还有另外两个概念，波动深度，(max-min)/max*100%；flicker index，闪烁指数，Flicker Index = (Area 1) / (Area 1 + Area 2)。
闪烁指数反映的是亮度的上下波动相对于平均亮度的幅度，平均亮度是人眼感受的亮度。用积分求平均亮度，平均亮度之上的部分和平均亮度之下的凹槽是上下振幅。这个指数明显比闪烁百分比更好，包含了形状的因素。假设一个方波，波动深度和调制深度是100%，占空比99.99%，那么即使频率很低，比如100hz，也基本没影响。
这个论文里也说了，形状、占空比也有影响，但尚未得到详细地研究。
The effects of flicker depend not only on the frequency of the flicker but also on the modulation depth and
on other waveform metrics such as flicker index and duty cycle. For visible flicker, the amplitude of the
Fourier fundamental predicts flicker fusion (de Lange Dzn [B26]). For invisible flicker, the effects of
different waveforms have not been studied in detail. The peak-trough modulation depth of the 100–120 Hz
flicker from older fluorescent lamps with magnetic ballasts varies with the component phosphors, some of
which exhibit persistence, varying the chromaticity of the light through its cycle (Wilkins and Clark
[B115]). The peak-trough modulation depth known to induce headaches from fluorescent lighting at
100 Hz is about 35% (Wilkins et al. [B116]). The present definitions for modulation do not distinguish the
difference between low-frequency and high-frequency modulation. But for sufficiently high flicker
frequencies, there appear to be limited human biological effects.
The upper limit of the low-risk region is the line Modulation (%) < 0.08×Frequency and corresponds to a
factor of about 2.5 above the NOEL. Below 90 Hz, the low-risk region satisfies Modulation (%) < 0.025×Frequency,
and the NOEL can be taken a factor of 2.5 below that to become Modulation (%) < 0.01×Frequency. The
conservativeness of the regions may be determined by further research, but based on the available data (see Clause 8),
the shaded regions contain the low-risk region.
论文里说调制深度和频率有如上对应关系。其实我更认为应该是flicker index和频率如类似如上的关系，但这个系数不知道怎么求。flicker index = a*f。
2018年12月30日 12点12分
14
频率的重要性没什么好说的，但闪烁百分比这个指标感觉不够。
percent flicker，闪烁百分比，modulation depth，调制深度，(max-min)/(max+min)*100%，完全没考虑形状。规则的图形，比如方波，其形状主要受占空比影响。不规则的更麻烦一些。还有另外两个概念，波动深度，(max-min)/max*100%；flicker index，闪烁指数，Flicker Index = (Area 1) / (Area 1 + Area 2)。
闪烁指数反映的是亮度的上下波动相对于平均亮度的幅度，平均亮度是人眼感受的亮度。用积分求平均亮度，平均亮度之上的部分和平均亮度之下的凹槽是上下振幅。这个指数明显比闪烁百分比更好，包含了形状的因素。假设一个方波，波动深度和调制深度是100%，占空比99.99%，那么即使频率很低，比如100hz，也基本没影响。这个论文里也说了，形状、占空比也有影响，但尚未得到详细地研究。
The effects of flicker depend not only on the frequency of the flicker but also on the modulation depth and
on other waveform metrics such as flicker index and duty cycle. For visible flicker, the amplitude of the
Fourier fundamental predicts flicker fusion (de Lange Dzn [B26]). For invisible flicker, the effects of
different waveforms have not been studied in detail. The peak-trough modulation depth of the 100–120 Hz
flicker from older fluorescent lamps with magnetic ballasts varies with the component phosphors, some of
which exhibit persistence, varying the chromaticity of the light through its cycle (Wilkins and Clark
[B115]). The peak-trough modulation depth known to induce headaches from fluorescent lighting at
100 Hz is about 35% (Wilkins et al. [B116]). The present definitions for modulation do not distinguish the
difference between low-frequency and high-frequency modulation. But for sufficiently high flicker
frequencies, there appear to be limited human biological effects.
The upper limit of the low-risk region is the line Modulation (%) < 0.08×Frequency and corresponds to afactor of about 2.5 above the NOEL. Below 90 Hz, the low-risk region satisfies Modulation (%) < 0.025×Frequency,
and the NOEL can be taken a factor of 2.5 below that to become Modulation (%) < 0.01×Frequency. The
conservativeness of the regions may be determined by further research, but based on the available data (see Clause 8),
the shaded regions contain the low-risk region.
论文里说调制深度和频率有如上对应关系。其实我更认为应该是flicker index和频率如类似如上的关系，但这个系数不知道怎么求。flicker index = a*f。
level 14
