A Survey of Visual Display Terminal Work by the Visually Impaired and Development of a New Type of Assistive Device

本研究包括视障人士使用视觉显示终端的实地调查和一种新型视障人士辅助装置的开发。通过对8名低视力VDT用户进行调查，他们发现，在闭路电视（CCTV）和个人电脑显示器之间频繁地移动视线位置，加上在CCTV下面操纵文本表的相关身体运动（主要是脖子和躯干），使工作压力很大，导致工作效率降低。为了解决这些问题，本文开发了一种新的弱视人群文本输入系统。该系统具有两个主要特点：一个显示两个屏幕的视觉显示单元（由“windows”操作系统执行的双窗口显示）和一个由脚踏开关操作的电源辅助文本表。在该系统中，两个项目同时显示在一个视觉显示单元上：放置在桌子上并由CCTV捕获的文本字段和文字处理程序的屏幕。使用X-Y记录器制作了电源辅助文本表。文本表允许操作员通过使用四个脚踏开关按钮将其移动到四个所需方向中的任何一个（在二维中）。双击其中一个开关使表迅速返回到参考点。为了对新系统进行评估，研究人员在两名低视力参与者的情况下，将其与普通的双显示器系统进行了比较。他们对新系统的评价是有利的，特别是在移动凝视位置时减少了长途旅行的眼球运动，以及操作电动辅助X-Y桌的便利性方面。重要的是，使用新系统的打字任务的性能大大提高。最后，研制了实用的新型助力X-Y表。

The research was composed of a field survey of visual display terminal work by visually Impaired persons and a development of a new type of assistive device for them.The survey by investigating eight low-vision VDT users visiting their workplaces showed that the frequent movement of the gaze position between a closed-circuit television (CCTV) and a personal computer display, plus the associated body movements (of mainly the neck and trunk) to manipulate a text table underneath the CCTV,made the work stressful and resulted in reduced work efficiency.To solve those problems, a novel system for text typing by low-vision persons has been developed and evaluated. The system is characterized by two main features : a visual display unit in shich two screens are displayd (a double windows display performed by 'WINDOWS' operating system) and a power-assisted text table operated by foot switches. In this system, two items are displayd simultaneously on one visual display unit : a field of the text placed on the table and captured by the CCTV,and the screen of a word processing program. The power-assisted text table was made using an X-Y recorder. The text table allows the operator to move it to any of four desired directions (in two dimensions) by using four foot switch buttons. Doubled clicks of one of the switches return the table to the reference point quickly.To evaluate the new system, it was compared with an ordinary two-displays system in the case of two low-vision participants. Their comments were favorable to the new system, especially concerning the decrease in long travel eye movements in shifting the gaze positions and concerning the ease of operating the power-assisted X-Y table. Importantly, the performance of typing tasks using the new system substantially improved.Finally, newly power-assisted X-Y table was developed for practical use.