Cell Phone-based Wayfinding for the Visually Impaired James Coughlan 1 , Roberto Manduchi 2 , and Huiying Shen 1 1 Smith-Kettlewell Eye Research Institute 2318 Fillmore Street San Francisco, CA 94115 {coughlan,hshen}@ski.org 2 University of California, Santa Cruz 1156 High Street Santa Cruz, CA 95064 manduchi@soe.ucsc.edu 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 in the environment (labeling locations such as offices and restrooms). Our main technical innovation is that we have designed these machine-readable signs to be detected and located in fractions of a second on the cell phone CPU, even at a distance of several meters. A linear barcode printed on the sign is read using novel decoding algorithms that are robust to noisy images. The information read from the barcode is then read aloud using pre-recorded or synthetic speech. We have implemented a prototype system on the Nokia 7610 cell phone, and preliminary experiments with blind subjects demonstrate the feasibility of using the system as a real-time wayfinding aid.