Traditional tactile diagrams use short braille keys and annotations to provide additional information as braille legends in separate pages. Visually impaired users have to perform tedious hand movements to flip back and forth between the Braille index page and the information pages for synthesizing and comprehending pictorial information. By leveraging the use of color tactile diagrams, we designed and developed ColorTact - a finger-wearable device that senses colors on the tactile diagram to retrieve the associated audio information through point-and-click interaction. In ColorTact, we designed a novel offset-clicking method to achieve an unobstructed tactile reading experience by maintaining the tactual perceptivity of the fingertips. We present the iterative design process involving 8 visually impaired users, a controlled experiment with 12 blindfolded users and a subjective evaluation with 8 visually impaired users to evaluate the performance of our offset-clicking technique and discuss its design implications. The use of ColorTact system can potentially reduce the volume of traditional tactile textbooks and also increase the efficiency of diagram reading.

Authors: Arshad Nasser, Kening Zhu, Taizhou Chen, Can Liu, PVM Rao