Navigation for visually impaired
A new concept for visually impaired pedestrians in buildings has been developed at the University of Nevada, Reno.
Indoor navigation systems for users who are visually impaired typically rely upon expensive physical augmentation (such as RFID tags) and sensing equipment - consequently few systems have been implemented.
But 'Navatar' - devised by four students at the University and running on a standard smartphone - navigates by exploiting the physical characteristics of indoor environments, using unique sensing abilities of impaired users together with minimalistic sensing achievable with low cost accelerometers and compasses in smartphones.
Dead reckoning (DR) is achieved by using the phone's accelerometer and compass - it is accurate enough in the short term, but not sufficient for longer distances, as errors accumulate with time.
So 'particle filters' are used to estimate the user's location, based on both the sensor data as well as the user confirming the presence of tactile landmarks along the path - the landmarks are extracted from a virtual representation of the environment, and allow for correction of DR error.
As touch screen devices are challenging for the visually impaired, directions are provided using synthetic speech and users confirm the presence of a landmark by verbal confirmation or by pressing a button on the phone or on a Bluetooth headset.
A benefit of this approach is that the user can leave the phone in their pocket - leaving both hands free for using a cane and recognizing tactile landmarks.
A user study with 12 blindfolded and 6 blind users has demonstrated the feasibility of the approach, locating the user to within 1.85 m.
Details from the links below.