Accessible spaces: navigating through a marked environment with a camera phone

We demonstrate a system designed to assist a visually impaired individual while moving in an unfamiliar environment. Small and economical color markers are placed in key locations, possibly in the vicinity of other signs (bar codes or text). The user can detect these markers by means of a cell phone equipped with a camera. Our demonstration highlights a number of novel features, including: improved acoustic interfaces; estimation of the distance to the marker, which is communicated to the user via text-to-speech (TTS); increased robustness via rotation invariance, which makes the system easier to use for users with reduced dexterity.