title: Crosswatch: a System for Providing Guidance to Visually Impaired Travelers at Traffic Intersections.
abstract: OBJECTIVE
  This paper describes recent progress on the "Crosswatch" project, a smartphone-based system developed for providing guidance to blind and visually impaired travelers at traffic intersections. Building on past work on Crosswatch functionality to help the user achieve proper alignment with the crosswalk and read the status of walk lights to know when it is time to cross, we outline the directions Crosswatch is now taking to help realize its potential for becoming a practical system: namely, augmenting computer vision with other information sources, including geographic information systems (GIS) and sensor data, and inferring the user's location much more precisely than is possible through GPS alone, to provide a much larger range of information about traffic intersections to the pedestrian.
  
  
  METHODS
  The paper summarizes past progress on Crosswatch and describes details about the development of new Crosswatch functionalities. One such functionality, which is required for determination of the user's precise location, is studied in detail, including the design of a suitable user interface to support this functionality and preliminary tests of this interface with visually impaired volunteer subjects.
  
  
  RESULTS
  The results of the tests of the new Crosswatch functionality demonstrate that the functionality is feasible in that it is usable by visually impaired persons.
  
  
  CONCLUSIONS
  While the tests that were conducted of the new Crosswatch functionality are preliminary, the results of the tests have suggested several possible improvements, to be explored in the future.
  
  
  CONCLUSIONS
  The results described in this paper suggest that the necessary technologies used by the Crosswatch system are rapidly maturing, implying that the system has an excellent chance of becoming practical in the near future.
  
  
  CONCLUSIONS
  The paper addresses an innovative solution to a key problem faced by blind and visually impaired travelers, which has the potential to greatly improve independent travel for these individuals.
authors.affiliation: The Smith-Kettlewell Eye Research Institute San Francisco, CA coughlan@ski.org , hshen@ski.org.
authors.forename: James M
authors.initials: JM
authors.lastname: Coughlan
authors.affiliation: The Smith-Kettlewell Eye Research Institute San Francisco, CA coughlan@ski.org , hshen@ski.org.
authors.forename: Huiying
authors.initials: H
authors.lastname: Shen
keywords: Assistive Technology; Blindness; Pedestrian Safety; Traffic Intersection; Visual Impairment