Study on the visibility of the Japanese sign language. The development of the evaluation method of dynamic modeling

日本手语是听力障碍者和正常人之间最有用的交流方式之一。手语是听力受损者完全依靠视觉的语言。与书面语言一样，如果手语不清晰，就会出现沟通问题，并出现疲劳。虽然手语视觉清晰度的重要性已得到社会认可，但尚未对这一问题进行系统研究。手语的可视性受各种视觉环境因素的影响。本研究的目的是阐明可视性与视觉环境因素之间的关系，并最终提出手语可视性的指导原则。手语的易读性受视力的影响，而手语的可视性受照度的影响，垂直照度越高，易读性值越高。当垂直照度超过100 lx时，有变暗的趋势.一般来说，座位越远或照度越低，受试者对条件的评价就越难以辨认。照度越低，距离的影响越大。即使在14.1 m点，1000 lx下的评价也不模糊。背景颜色之间的可见性没有区别。受试者指出的说话者的不清晰部分是说话者的外貌和嘴唇的运动。这是因为受试者从他们看到的手语中得到了线索。在低照度下，正常人的平均评价比听障人差。在教学现场使用影像设备时照度不足，应检查照度和投光照明方式。

Japanese sign language is one of the most useful methods of communication between hearing-impaired and hearing people. Sign language is language for hearing-impaired people that relies entirely on vision. As is the case with written language, if sign language is not legible, communicate problems occur and fatigue sets in. Though the importance of the visual clarity of sign language is socially recognized, systematic studies of the problem have not been carried out. Thevisibility of sign language is influenced byvarious visual environmental factors. The purpose of the present study is to elucidate the relationships between the visibility and the visual environmental factors and finally to propose guidelines for sign language visibility.The legibility of the sign language is influenced by thevisual acuity, but thevisibility of the sign language is influenced by the illuminance.The legibility value is high as vertical illuminance becomes higher. And when vertical illuminance become over 100 lx, the tendency is gettingdull. In general the further the seat or the lower the illuminance is, the more illegible the subject evaluated the conditions. The lower the illmuninace is, the more the effect of the distance is. The evaluation at 1000 Ix was not illegible even at 14.1 m point. There is no difference in the visibility between the colors of the background. The parts of the speaker which the subjects pointed out illegiblewere the speaker's aspect and the movement of the lips. This is owing to the fact that the subjects got clues from them in seeing the sign language. The average evaluation for normal people was worse than the hearing-impaired people at the low illuminances. The illuminance in using image equipment in the lecture field is insufficient.It is necessary toexamine illuminance and floodlightingmethod in the case.