EURASIP Journal on Image and Video Processing
Volume 2007 (2007), Article ID 96357, 13 pages
doi:10.1155/2007/96357
Research Article
Color Targets: Fiducials to Help Visually Impaired People Find Their Way by Camera Phone
1Rehabilitation Engineering Research Center, Smith-Kettlewell Eye Research Institute, San Francisco 94115, CA, USA
2University of California, Santa Cruz 95064, CA, USA
Received 16 January 2007; Revised 10 May 2007; Accepted 2 August 2007
Academic Editor: Thierry Pun
Copyright © 2007 James Coughlan and Roberto Manduchi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
A major challenge faced by the blind and visually impaired population is that of wayfinding—the
ability of a person to find his or her way to a given destination. We propose a new wayfinding aid
based on a camera cell phone, which is held by the user to find and read aloud specially designed
machine-readable signs, which we call color targets, in indoor environments (labeling locations
such as offices and restrooms). Our main technical innovation is that we have designed the color
targets to be detected and located in fractions of a second on the cell phone CPU, even at a distance
of several meters. Once the sign has been quickly detected, nearby information in the form of a
barcode can be read, an operation that typically requires more computational time. An important
contribution of this paper is a principled method for optimizing the design of the color targets
and the color target detection algorithm based on training data, instead of relying on heuristic
choices as in our previous work. We have implemented the system on Nokia 7610 cell phone,
and preliminary experiments with blind subjects demonstrate the feasibility of using the system as
a real-time wayfinding aid.