Image-based haptic texture rendering

In this paper, we present a new image-based method to display haptic texture information extracted from a static two dimensional image. The three dimensional forces allow the user to feel the contours and textures of the image with sufficient realism using haptic devices. The texture force is decomposed into a normal force component and a tangential force component at the haptic interaction point. The magnitude of the normal force is determined either by the color temperature (i.e. the emotions of warmth/coolness evoked by colors) or the luminance values in images. Warmer/brighter colors determine stronger normal forces to generate bumps, and cooler/darker colors determine weaker normal forces to produce depressions. The tangential force describes the relative color variation between haptic interaction point and its neighbors, thus, can be considered as a descriptor of the local texture feature. Because it is oriented to the pixels with cooler color in the neighborhood, when the user is exploring the bump by a haptic device, tangential resistive forces are sent to the user until the top of the bump is reached and, after the top, the virtual probe is pulled in the other direction. Our force model is by means of simple image processing techniques. The calculation is totally done by local, independent and direct operation. In other words, global operation such as recovering height maps is not necessary.