Tangible images

Visual and haptic rendering pipelines exist concurrently and compete for computing resources while the refresh rate of haptic rendering is two orders of magnitude higher than that of visual rendering (1000 Hz vs. 30-50Hz). However, in certain cases, 3D visual rendering can be replaced by merely displaying 2D images, thus releasing the resources to image-driven haptic rendering algorithms. A number of approaches have been proposed to provide haptic interaction with 2D images but they suffer from various problems and do not provide a fully believable impression of haptic sensation of the 3D scene displayed in the image. Based on the method of haptic effect generation, the existing approaches can be classified into techniques that use information derived from the image, and techniques that use additional information along with the image to enable haptic interaction. Previously, we proposed our own method of augmenting images with haptic data for using them in shared virtual environments [Rasool and Sourin 2010]. The images were augmented with invisible haptic objects defined by implicit, explicit and parametric mathematical functions using the function-based extension of the Virtual Reality Modeling Language [Wei and Sourin, 2011].