senescent changes in color discrimination -To the interface design for elderly users-

本研究采用心理物理学方法研究了人类颜色辨别能力的衰老变化。波长辨别能力随年龄增长而增强。该增量具有统计学显著性。这表明，即使视网膜上的照度通过亮度的个体调节是恒定的，颜色辨别能力也随着年龄的增长而降低。在美国也进行了这项测量，以计算不同种族的影响，如瞳孔的颜色的差异，但没有种族之间的实际差异。分析表明，随着年龄的增长，敏感性降低，不仅对颜色的歧视介导的黄蓝色的对手机制（S-锥），正如已经知道的，但也对颜色的歧视介导的红绿色的对手机制（L-和M-锥）。噪声比对信号的增加导致sens相对较大的降低 ...更多信息 但这种噪声增量本身对由L-和M-视锥介导的颜色辨别的影响很小。由S-锥介导的辨别力的与噪声相关的变化可以通过模型中的噪声参数的变化来描述。然而，为了描述由L-和M-视锥介导的辨别力的年龄相关变化，不仅需要噪声参数，而且需要两个参数：视网膜上的L-和M-视锥的比率和红绿色对立通道与亮度通道之间的信号比率。因此，很难预测敏感度随年龄的变化，因为这两个参数在观察者之间是不同的，但与年龄无关。颜色外观是相对稳定的，即使眼介质密度增加，因为信号放大。然而，作为信号放大的结果，生物噪声如自放电也被放大，并导致信噪比增加。因此，在色彩信号相对小的情况下，即使视网膜照度被调节为常数，色彩辨别的灵敏度也随着年龄而降低。它导致老年人丧失了对颜色的辨别能力，几乎没有主观症状。对于老年用户的界面设计，最好避免颜色协调，因为色度信号很小，需要在白色周围进行颜色区分。相反，我们应该使用颜色协调，使用于区分的颜色信号，如红色，绿色，黄色和蓝色，将足够强。少

In this research, senescent changes in color discrimination on human observers were investigated with psychophysical method. Thresholds in wavelength discrimination increased with age. This increment was statistically significant. This indicates that even the illuminance on the retina is constant by individual adjustment of luminance, ability of color discrimination reduces with age. This measurement is also performed in United States to figure out the effect of different races like difference of the color of pupil, but there is no actual difference between races.Experimental results were analyzed by color discrimination model. The analysis shows that sensitivities reduce with age not only on chromatic discrimination mediated by yellow-blue chromatic opponent mechanism (S-cones), as already known, but also on chromatic discrimination mediated by red-green chromatic opponent mechanism (L- and M-cones). Increment of noise ratio against signal causes the relatively-large reduction of sens … More itivity on chromatic discrimination mediated by S-cone but this noise increment itself is little on chromatic discrimination mediated by L- and M-cones. Age-related change in discrimination mediated by S-cone can be described by the change of a noise parameter in the model. However, in order to describe the age-related change in discrimination mediated by L- and M-cones, it is required that not only the noise parameters, but also two parameters ; ratio of L- and M-cones on the retina and signal ratio between red-green chromatic opponent channel and luminance channel. Thus, it is difficult to predict the change of sensitivity with age because these two parameters are different between observers but regardless of age.Color appearance is relatively stable with age even the ocular media density increases because of signal amplification. However, as the result of signal amplification, biological noise like self-firing is also amplified and causes the increment of signal/noise ration. Thus, in the case that chromatic signal is relatively small, sensitivity of chromatic discrimination decreases with age even the retinal illuminance is adjusted to the constant. It causes the problem that elderly people loose the ability of color discrimination with almost no subjective symptom. To the interface design for elderly users, it is better to avoid the color coordination which require the color discrimination around white because of small chromatic signals. Instead, we should use the color coordination which make the chromatic signal used for discrimination, like red, green, yellow and blue, would be enough strong. Less