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

日本手语是听障人士和正常人之间最有用的交流方式之一。手语是为听力受损的人提供的完全依靠视觉的语言。就像书面语言一样，如果手语不清晰，沟通就会出现问题，并且会感到疲劳。虽然手语视觉清晰度的重要性已得到社会的认可，但对这一问题的系统研究尚未开展。手语的可见性受到各种视觉环境因素的影响。本研究旨在探讨手语可见性与视觉环境因素之间的关系，并提出手语可见性的指导原则。手语的易读性受视觉敏锐度的影响，而可见性受照度的影响。垂直照度越高，易读值越高。而当垂直照度超过100 lx时，则趋于暗淡。一般来说，座位越远或照度越低，受试者评估的条件就越难以辨认。光照越低，距离的影响越大。即使在14.1 m点，1000 Ix时的评价也不模糊。背景颜色之间的可见性没有差别。被调查者指出说话人身上难以辨认的部分是说话人的外貌和嘴唇的动作。这是因为受试者在看到手语时从中得到了线索。在低照度下，正常人的平均评价低于听障者。讲座现场使用影像设备的照度不足。在这种情况下，有必要检查照度和泛光灯照明方法。

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.