Abstract
Touchscreens are a reconfigurable and updateable alternative to numerous analog interfaces, but despite their name provide limited or no touch sensations during interaction. Emerging surface haptic technology has reintroduced some tactile effects such as texture and button clicks, and holds promise for enhancing dexterous control during tasks such as contour drawing which require simultaneous generation and sensing. Existing haptic display feedback for contour drawing is primarily restricted to niche and expensive products for blind accessibility; these employ a range of touch interaction methods whose comparative advantages and optimal strategies remain unclear. This study compares three such tactile interaction methods for contour drawing using a refreshable pin array; input directly on the pin surface with a finger, input on the surface using a stylus, and input on a peripheral screen while the tactile feedback is felt on the pin surface with one's other hand. Implementation considerations are detailed in collaboration with a blind since birth co-author, particularly regarding tool tracking on a dynamic surface and bi-manual touch interaction. A user study investigating performance of intended contour generation across the different methods found that contour complexity had greater impacts on accuracy than interaction method, and that higher accuracy does not always correlate with user confidence across methods. Experimental observations highlight several strategies and hand postures users adopted to leverage each interaction method, and can serve as a guide to developing robust haptic feedback systems for contour drawing on future iterations of surface haptic interface technology.
