Eelke Folmer
Human Computer Interaction Research
University of Nevada, Reno

Navatar: Navigating Blind Users in Indoor Spaces using Tactile Landmarks

Indoor navigation systems for users who are visually impaired typically rely upon expensive physical augmentation of the environment or expensive sensing equipment; consequently few systems have been implemented. We present an indoor navigation system called Navatar that allows for localization and navigation by exploiting the physical characteristics of indoor environments, taking advantage of the unique sensing abilities of users with visual impairments, and minimalistic sensing achievable with low cost accelerometers available in smartphones.

How it works

outside navigation is more unconstrained dead reckoning localization navatar combines dead reckoning with periodic sensing
veering
dead reckoning
user confirming landmarks

For outdoor navigation, localization with high precision is required as users are more likely to veer. In indoor environments navigation is much more constrained by physical infrastructure such as walls and doors and veering is less likely to occur. Precise localization comes at a significant higher cost; as augmenting indoor environments with RFID tags is often prohibitively expensive. To facilitate large-scale deployment of an indoor navigation system, less precise but less expensive localization solutions need to be explored. Dead reckoning localization is cheap and can be achieved using sensors (accelerometer/compass) already present in current mobile devices. Dead reckoning is relative accurate for short distances but inaccurate for longer distances as errors accumulate of time.

Particle filters are used to estimate the user's location based on the sensor data as well as the user confirming the presence of tactile landmarks along the provided path that are extracted from a virtual representation of the environment, which allows for mitigating the error of dead reckoning. This type of interaction seamlessly integrates with how users with visual impairments navigate familiar spaces as this includes the identification of known tactile landmarks. Navatar has a high possibility of large-scale deployment, as it only requires an annotated virtual representation of an indoor environment, for example, created in Google Sketchup. A user study with 12 blindfolded and six blind users demonstrates the feasibility of our approach and shows we can locate the user with 1.85 meter accuracy. We identify several areas for improvement.

Media

landmarks can be annotated on a 3d model
Landmarks used for navigation, can be annotated on a 3D model by harnessing crowdsourcing efforts.

Publicity

New Scientist - Robot sensing and smartphones help blind navigate
ACM Technews - University of Nevada, Reno Scientists Design Low-Cost Indoor Navigation System for Blind
Redorbit - Indoor Navigation System Gives Guide Dogs A Rest
Phys.org - Scientists design indoor navigation system for blind
Gizmag - Navatar system could help the blind navigate indoors

Publications

Ilias Apostolopoulos, Navid Fallah, Eelke Folmer, Kostas Bekris. Integrated Online Localization and Navigation for People with Visual Impairments using Smart Phones, Accepted for ACM Transactions on Interactive Intelligent Systems, to appear.

Navid Fallah, Ilias Apostolopoulos, Kostas Bekris, Eelke Folmer, Indoor Human Navigation Systems; A survey, Interacting with Computers, Oxford Journals. 25:1 Pages 21-33, February 2013. [bibtex]

Navid Fallah, Ilias Apostolopoulos, Kostas Bekris, Eelke Folmer, The User as a Sensor: Navigating Users with Visual Impairments in Indoor Spaces using Tactile Landmarks, Proceedings of the 2012 ACM annual conference on Human Factors in Computing Systems (CHI'12), Pages 425-432, Austin, Texas, May 2012. [bibtex] [23% acceptance rate]

Ilias Apostolopoulos, Navid Fallah, Eelke Folmer, Kostas Bekris, Integrated Online Localization and Navigation for People with Visual Impairments using Smart Phones, IEEE International Conference on Robotics and Automation (ICRA), Pages 1322 -1329, Minnesota, MN, May, 2012. [bibtex] [40% acceptance rate]

Ilias Apostolopoulos, Navid Fallah, Eelke Folmer, Kostas Bekris. Feasibility of Interactive Localization and Navigation of People with Visual Impairments, Proceedings of 11th Intelligent Autonomous Systems Conference, Pages 22-32, Ottawa, Ontario, August 2010. [bibtex]