Length Perceptual Characteristics on Raised-Dot Slippages

Abstract

If line-shape information was physically presented by virtue of some kind of mechanical interface, man-machine communication would be enhanced in the sense of multi-modal interactions. In order for such interactions to be available with ease, they should be realized as simple, small, and cheap devices even though suffering from a bit of performance decrease. Thus, the authors have studied a mouse-like computer-human mechanical interface. The idea is that slippage stimuli on a fingerpad would be effective enough to provide users a piece of motion information, and that the mechanism for slippage can be embodied in mouse interfaces. Here, to enhance the slippage perceptual performance, raised-dots were considered to be useful, and thus, a series of psychophysical experiments were carried out by using raised-dot planes with the period of 1.5, 3.1, 12.5, 30, and 50 mm, together with a without-dot flat plane. It was confirmed that the perceptual lengths were well formulated by a power law: they were proportional to the power of both speed and length. The exponential constants with the length factor were a little less than 1 corresponding to the ideal linear relationship. While the ones with the speed factor were in negative, nearly 0 corresponding to the ideal undisturbed relationship. Then, it was found that the pathway length perceptual accuracies for the raised-dot planes were much superior to that for the flat plane from the viewpoint of (1) length-related perceptual length contractions, (2) speed-induced perceptual length contractions, and (3) perceptual length random errors. This is shown in this chapter.