Instrument for Haptic Image Exploration

Haptic image exploration is intriguing because of the need to find an effective method to transfer image content from the visual to the haptic sensing modality. While in the past, the research community has been primarily focused on the exploration of restricted types of images, e.g., maps or mathematical curves, we address the challenging problem of haptic rendering of general photographs. We represent the photographs as 3-D grooves on a 2-D image plane as haptic contours. We discuss our interactive image segmentation tool to extract these contours from an image in an object-level hierarchy, i.e., the contours have a hierarchical relationship that represents how image objects consist of parts. Our haptic image exploration instrument allows a user interact with the image by zooming and panning but our major contribution is the support for browsing multiple levels-of-detail (LODs) of the contour image. We show that multiple LODs help a user to understand an image more readily. We also investigate if ambient encoding of the spatial surrounding of the haptic cursor in the image is beneficial during exploration. We present the results of a user study to evaluate the efficacy of multiple LODs and of ambient encoding of the spatial surrounding through textures.