Predicting the effects of vertical vibration frequency, combinations of frequencies and viewing distance on the reading of numeric displays
Abstract
This paper describes a series of experiments to determine the effects of vibration frequency, viewing distance and multiple frequency motions on the reading of numeric characters. Contours of vertical ( z-axis) whole-body vibration levels resulting in equal degradation of the reading task were determined over the frequency range 2·8 Hz to 63 Hz. With the seating condition employed, the task was found to be most sensitive to vibration acceleration at a frequency of 11·2 Hz. A marked correlation was observed between reading error and reading speed. The effects of vibration on reading performance were found to be dependent on viewing distance for distance of less than 1·5 m, with the effect increasing as the viewing distance was decreased. The effect of 3·15 Hz vibration was found to increase more rapidly with reductions in viewing distance than that of 16 Hz vibration. The effects of 3·15 and 16 Hz vibration were independent of viewing distance greater than 1·5 m, indicating that the effects of rotational eye motion are dominant at these distances. Four methods were compared for predicting the effects of multiple frequency motion on reading performance given a knowledge of the effect of each component alone. The best predictions of reading error were obtained from the most severe weighted spectral component alone. Inspection of individual subject's data suggests that in many cases the effect of multiple frequency vibration on reading is even less than the effect of the largest sinusoidal component alone.
- Publication:
-
Journal of Sound Vibration
- Pub Date:
- June 1980
- DOI:
- 10.1016/0022-460X(80)90305-3
- Bibcode:
- 1980JSV....70..355L