Unified glare rating (UGR), which is a general discomfort-glare index, targets design objects such as artificial lighting. Light-source size, position of gaze, etc. are limited to the specific range assumed in the process of developing UGR. Because it is necessary to reflect human visual characteristics to universally predict the rating of discomfort glare according to visual science, it is necessary to understand the effects of visual characteristics on discomfort glare. In this study, which was conducted to systematically investigate visual characteristics in the visual field of discomfort glare, the effects of the solid angle and eccentric angle of the light source on the borderline between comfort and discomfort (BCD) luminance of discomfort glare were experimentally investigated. The results of the experiment revealed that the effect of light-source solid angle on BCD luminance depends on the eccentric angle. The results confirm the necessity of understanding the visual characteristics in terms of the effects of size and position of the light source on discomfort glare.
Diminished visibility in dim light degrades performance and safety on real-world tasks that depend on the timely detection of visual targets. The goals of this paper are to: 1. review factors that affect nighttime visibility, with an emphasis on driving, 2. provide the reader with online access to an automated modified Adrian/CIE visibility level (VL) calculator (VLC), and 3. suggest future research for enhancing the objective measurement of visibility. Recognizing that luminance contrast is the primary sensory determinant of nighttime visibility, several contrast-detection models have been proposed to quantify visibility in dim lighting. Of these, the Adrian (1989) model accounts for comparatively more of the important variables and has been the most widely accepted. The mathematical steps for calculating target VL in the modified Adrian/CIE model are presented and the VLC user interface is explained in step-by-step order. The VLC provides an easy-to-use tool for calculating target VL. Several additional factors that affect VL that are not currently included in the model provide important research opportunities for enhancing the measurement of target visibility in nighttime conditions. The VLC is an open-access application intended to foster the measurement of VL in professional practice and to foster research to advance the utility of the Adrian/CIE model.
We evaluated the performance of light focus in an existing otoscope with a headlight employing an LED source. The mechanism of the otoscope was shown, and a coordinate system was set in the otoscope to evaluate the light-focusing performance. Experimental equipment based on the set coordinate system was built using the existing otoscope and headlight. We demonstrated experimental methods for measuring illuminance at the narrow mouth in the otoscope using the built experimental equipment. In the experiments conducted using the experimental methods, the performance of light focus in the existing otoscope was evaluated by measuring the illuminance. The optimal new otoscope for focusing light was designed using a headlight employing the LED source. The otoscope was built using the results obtained by the designs. We evaluated the performance of light focus in the designed otoscope with the otoscopes we built. The experimental equipment was built with the constructed otoscope and the headlight. We demonstrated experimental methods for measuring illuminance at the narrow mouth in the otoscope using the built experimental equipment. In the experiments conducted using the experimental methods, the performance of light focus in the designed otoscope was evaluated by the measured illuminance.