A comparison of two control-display gain measures for head-controlled computer input devices

Area of Science:

• Human-Computer Interaction
• Biomedical Engineering
• Ergonomics

Background:

• Head-controlled computer input devices offer an alternative interaction method.
• Evaluating control-display gain measures is crucial for optimizing user performance.
• Existing gain measures, like angle/angle (A/A), may be sensitive to environmental factors such as viewing distance.

Purpose of the Study:

• To compare the efficacy of two control-display gain measures: angle/angle (A/A) gain and displacement/angle (D/A) gain.
• To determine which gain measure is more robust to variations in viewing distance for head-controlled computer input.
• To identify optimal gain settings for improved operator performance in target acquisition tasks.

Main Methods:

• A discrete target acquisition task with circular targets was employed.
• Operator performance was assessed across three viewing distances and three gain settings for both A/A and D/A gain measures.
• Key performance metrics included movement time and root mean squared (RMS) cursor deviation.

Main Results:

• Increased viewing distance led to higher movement time and RMS cursor deviation with A/A gain settings (0.75 and 1.0).
• No significant effect of viewing distance on performance was observed for any D/A gain settings.
• Optimal performance, indicated by minimum movement time, was achieved with D/A gain settings of 0.5 cm/degree and 0.67 cm/degree.

Conclusions:

• Displacement/angle (D/A) gain appears more suitable for head-controlled computer input devices due to its insensitivity to viewing distance.
• The stability of D/A gain may stem from consistent angular head movement and kinesthetic feedback regardless of viewing distance.
• Further research into D/A gain could lead to more reliable and user-friendly head-controlled interfaces.