Absolute and Differential Thresholds of Motion Effects in Cardinal Directions

In this paper, we report both absolute and differential thresholds for motion in the six cardinal directions as comprehensively as possible. As with general 4D motion effects, we used sinusoidal motions with low intensity and large frequency as stimuli. Hence, we could also compare the effectiveness of motion types in delivering motion effects. We found that the thresholds for the z-axis (up-down) were higher than those for the x-axis (front-back) and y-axis (left-right) in both kinds of thresholds and that the type of motion significantly affected both thresholds. Further, between differential thresholds and reference intensities, we found a strong linear relationship for roll, yaw and, surge. Compared to them, a relatively weak linear relationship was observed for the rest of the motion types. Our results can be useful for generating motion effects for 4D contents while considering the human sensitivity to motion feedback.