%0 Journal Article
%T Length and Roughness Perception in a Moving-Plateau Touch Display
%A Junji Watanabe
%A Yusuke Godai
%A Hideyuki Ando
%J Advances in Human-Computer Interaction
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/764629
%X We have proposed a tactile geometry display technique based on active finger movement. The technique uses a perceptual feature that, during finger movement, the length of a touched object is perceived to increase when the object is moved in the same direction as the finger movement or to decrease when it is moved in the opposite direction. With this display technique, a wide range of tactile shapes can be presented with realistic rigid edges and continuous surfaces. In this work, to further develop our technique, we performed psychophysical experiments to study perceptions of length and roughness under this presentation technique. The results indicated that the elongation (shrinkage) of the object can be observed regardless of the roughness of the touched object and that the perceived roughness of the object slightly changes but the changes are much smaller than those theoretically expected. 1. Introduction 1.1. Moving-Plateau Touch Display When we touch an object in a space, we actively move our fingers across its surface. Since the cutaneous signals sequentially presented to the fingertips are integrated with proprioceptive signals of the finger and arm, we can perceive the shape and texture of the object, even if it is larger than the fingertips. The interplay of the cutaneous and proprioceptive sensations is essential for developing touch displays, and we have proposed a novel touch display technique for presenting tactile geometry based on the perceptual features of the two sensory processes [1¨C3]. Touched objects do not usually move during exploratory finger movements, but if the object moves during the finger movement, an illusory shape of the object can be perceived. As shown in Figure 1(a), when the object moves in the same direction as the finger, the length of the object is perceived to increase. Conversely, when the object moves in the opposite direction as in Figure 1(b), its length is perceived to decrease. This is because the human tactile system judges the length based on the initial and final positions of the moving edges, even if the information about the object¡¯s movement exists on the fingertip. In this touch display technique, called the Moving-Plateau Touch Display (MPTD), the extent of the change in the perceived length can be controlled by manipulating the velocity of the object during the finger movement. In this paper, we verify the generality of our display technique from the results of psychophysical experiments on the perceptions of length and roughness under the MPTD presentation. Figure 1: The principle of MPTD. (a) When
%U http://www.hindawi.com/journals/ahci/2012/764629/