Andre J, Owens D A
Virginia School of Psychology, James Madison University, Harrisonburg 22807, USA.
Hum Factors. 2001 Winter;43(4):620-30. doi: 10.1518/001872001775870331.
Visual recognition functions, such as acuity and contrast sensitivity, deteriorate rapidly over the declining luminances found during civil twilight. Thus civil twilight, a critical part of the transition between daylight and darkness, represents lighting conditions that may be useful to describe artificial illumination. Automotive headlamps project a three-dimensional beam that ranges from illumination levels comparable to daylight at the vehicle to the dark limit of civil twilight (3.3 1x) at some distance ahead. This twilight envelope is characterized as a distance beyond which foveal visual functions are severely impaired, and thus it provides a general, functional description of the useful extent of the headlamp beam. This user-centered approach to describing illumination is useful for characterizing visibility when driving at night or in other artificially lit environments. This paper discusses the twilight envelope approach and its application to intervehicle variations in headlamp systems. Actual or potential applications of this research include user-centered description of artificial illumination and driver/pedestrian safety education.
视觉识别功能，如视敏度和对比敏感度，在民用曙光期间亮度下降时会迅速恶化。因此，民用曙光作为白天与黑夜过渡的关键部分，代表了可能有助于描述人工照明的光照条件。汽车前照灯投射出一个三维光束，其范围从车辆处与日光相当的照明水平到前方一定距离处民用曙光的暗极限（3.3勒克斯）。这个曙光包络被定义为一个距离，超过这个距离中央凹视觉功能会严重受损，因此它提供了前照灯光束有效范围的一般功能描述。这种以用户为中心描述照明的方法对于描述夜间驾驶或其他人工照明环境中的能见度很有用。本文讨论了曙光包络方法及其在前照灯系统车辆间差异中的应用。本研究的实际或潜在应用包括以用户为中心描述人工照明以及驾驶员/行人安全教育。
