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

该研究包括视障人士视觉显示终端工作情况的实地调查和一种新型视障人士辅助设备的开发。通过对8名低视力VDT用户访问工作场所的调查发现，闭路电视(CCTV)和个人电脑显示器之间凝视位置的频繁移动，以及相关的身体运动(主要是颈部和躯干)来操纵CCTV下的文本台，使工作压力增加，导致工作效率下降。为了解决这些问题，开发并评估了一种新型的低视力VDT用户文本打字系统。该系统的主要特点有两个：一个是视觉显示单元，两个屏幕显示(双窗口显示由Windows操作系统执行)和一个由脚踏开关操作的电动辅助文本台。在该系统中，两个项目同时显示在一个可视显示单元上：放置在桌子上并由CCTV捕获的文本的字段和文字处理程序的屏幕。动力辅助文本表是用X-Y记录器制作的。文本工作台允许操作员使用四个脚踏开关按钮将其移动到四个所需方向(二维)中的任何一个。在两个低视力参与者的情况下，将新系统与普通的双显示器系统进行了比较，以评估新系统的性能。他们的评论对新系统是有利的，特别是关于在转移凝视位置时长途旅行眼球运动的减少，以及关于动力辅助X-Y工作台的操作的简便性。重要的是，使用新系统的打字任务的性能有了很大的提高。最后，开发了一种新的动力辅助X-Y工作台，并用于实际应用。

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.