A mobility device for the blind with improved vertical resolution using dynamic vision sensors

We propose an improved version of a wearable lightweight device to support visually impaired people during their everyday lives by facilitating autonomous navigation and obstacle avoidance. The system deploys two retina-inspired Dynamic Vision Sensors for visual information gathering. These sensors are characterized by very low power consumption, low latency and drastically reduced data rate in comparison with regular CMOS/ CCD cameras which makes them well suited for real-time mobile applications. Event-based algorithms operating on the visual data stream extract depth information in real-time which is translated into the acoustic domain. Spatial auditory signals are simulated at the computed origin of visual events in the real world. These sounds are modulated according to the position in the field of view which the user can change by moving their head. Here, different tests with eleven subjects are conducted to evaluate the performance of the system. These tests show that the modulation helps to improve object localization performance significantly in comparison to prior experiments. Further trials estimate the visual acuity a user of the device would have using the Landolt C test. The low power consumption of all integrated components in a final system will allow for a long lasting battery life of a small portable device, which might ultimately combine perceived visual information and environmental knowledge to provide a higher quality of life for the visually impaired.