A comparison of two control-display gain measures for head-controlled computer input devices
We compared two gain measures: One, defined as angle/angle (A/A) gain, is the ratio between the angle subtended by displacement of the cursor and the corresponding angle of head extension/flexion or rotation. The alternative measure, defined as displacement/angle (D/A) gain, is the ratio between the...
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Published in | Human factors Vol. 38; no. 3; p. 390 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.09.1996
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Subjects | |
Online Access | Get more information |
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Summary: | We compared two gain measures: One, defined as angle/angle (A/A) gain, is the ratio between the angle subtended by displacement of the cursor and the corresponding angle of head extension/flexion or rotation. The alternative measure, defined as displacement/angle (D/A) gain, is the ratio between the linear displacement of the cursor on the screen and the corresponding angle of head extension/ flexion or rotation. A discrete target acquisition task using circular targets was used to compare control-display gain measures. Operator performance was evaluated for three viewing distances and three gain settings of each measure. Average movement time and root mean squared (RMS) cursor deviation from a straight line path increased as viewing distance increased for A/A gain settings 0.75 and 1.0. That no significant distance effect was observed for any of the D/A gain settings indicated that it might be more suitable to fix D/A gain rather than A/A gain for head-controlled computer input devices. Minimum movement time occurred for D/A gain settings of 0.5 cm/degree and 0.67 cm/degree. One explanation for the observed insensitivity of performance to changes in viewing distance with a fixed D/A gain may be that both angular head movement and the accompanying kinesthetic feedback do not change for a specified cursor displacement as viewing distance is changed. |
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ISSN: | 0018-7208 |
DOI: | 10.1518/001872096778702042 |