Lin M L, Radwin R G, Vanderheiden G C
Department of Industrial Engineering, University of Wisconsin-Madison 53706.
Ergonomics. 1992 Feb;35(2):159-75. doi: 10.1080/00140139208967804.
The purpose of this study was to use a Fitts' task to (1) determine how control-display gain influences performance using a head-controlled computer input device; (2) compare relative sensitivity to gain and optimal gain between head control and hand/arm control; and (3) investigate control-display gain interactions with other task factors including target width, movement amplitude and direction. The task was a discrete target acquisition task using circular targets of 2.9 mm, 8.1 mm, and 23.5 mm, movement amplitudes of 24.3 mm and 61.7 mm, and eight radial directions including 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees. Each device was operated at four gain levels. Ten subjects participated. The results indicated that gain had a significant effect on movement time for both types of pointing devices and exhibited local minimums. Discrete target acquisition at all gains was aptly described using Fitts' Law for both input devices. The mouse gain resulting in minimum movement time and RMS cursor deviation was between 1.0 and 2.0. The minimum movement time and RMS cursor deviation for the head-controlled pointer occurred at a gain between 0.3 and 0.6. Average movement time at the optimal head-controlled pointer gain had a slope of 169 ms/bit and was more than 76% greater than at the optimal mouse gain with a slope of 135 ms/bit. In addition, average RMS displacement was more than 27% greater for the head-controlled pointer at its optimal gain setting than for the mouse. Gain had the greatest effect for small target widths and long movement amplitudes using the head-controlled pointer. Average movement time increased 37% when increasing the head-controlled pointer gain from 0.6 to 1.2 for the small target width, but only increased 0.3% when increasing gain for the large target width. Average movement time also increased 12% when decreasing the head-controlled pointer gain from 0.3 to 0.15 for the long movement amplitude, but decreased 0.3% when decreasing gain for the short movement amplitude.
（1）确定控制显示增益如何影响使用头部控制的计算机输入设备的性能；（2）比较头部控制与手/臂控制之间对增益的相对敏感度和最佳增益；（3）研究控制显示增益与其他任务因素（包括目标宽度、移动幅度和方向）之间的相互作用。该任务是一个离散目标获取任务，使用直径为2.9毫米、8.1毫米和23.5毫米的圆形目标，移动幅度为24.3毫米和61.7毫米，以及八个径向方向，包括0度、45度、90度、135度、180度、225度、270度和315度。每个设备在四个增益水平下运行。十名受试者参与。结果表明，增益对两种类型的指向设备的移动时间都有显著影响，并呈现出局部最小值。对于两种输入设备，在所有增益下的离散目标获取都可以用菲茨定律恰当地描述。导致最小移动时间和均方根光标偏差的鼠标增益在1.0到2.0之间。头部控制指针的最小移动时间和均方根光标偏差出现在增益为0.3到0.6之间。头部控制指针在最佳增益下的平均移动时间斜率为169毫秒/比特，比最佳鼠标增益下的斜率135毫秒/比特高出76%以上。此外，头部控制指针在最佳增益设置下的平均均方根位移比鼠标大27%以上。对于头部控制指针，增益对小目标宽度和长移动幅度的影响最大。对于小目标宽度，将头部控制指针增益从0.6增加到1.2时，平均移动时间增加了37%，但对于大目标宽度增加增益时，平均移动时间仅增加了0.3%。对于长移动幅度，将头部控制指针增益从0.3降低到0.15时，平均移动时间也增加了12%，但对于短移动幅度降低增益时，平均移动时间减少了0.3%。
