A Smartphone-based Haptic Vision Substitution system for the blind

Haptic Vision Substitution is a relatively new Human-Machine Interface (HMI) designed to help the blind to `see´ through touch. This paper documents the implementation and design of a Smartphone-based vibrotactile system that uses Catadioptric stereo imaging to increase the spatial awareness of a visually impaired individual. The system computes a disparity map, where distance from an object is inversely proportional to the intensity, using Computer Vision techniques. This information is then compressed and sent to a microcontroller via Bluetooth to be actuated on an 8×8 matrix of shaftless coin vibration motors composing the vibrotactile interface. The interface is built into a wearable vest, where actuation occurs on the upper back region. The upper back was chosen as it is a relatively unused area of the body, providing minimal contraction, and has the somatosensory neuron resolution to accommodate an 8×8 vibrotactile array. This study also includes research on the effectiveness of the haptic transduction and methods of enhancing the tactile sensation to provide a more seamless user experience. It also builds the basis for a programmable tactile interface that would open the doors to a variety of applications for the blind.