SEATTLE, Aug. 19 (UPI) -- University of Washington researchers say they are testing the first video phone that transmits American Sign Language over the U.S. cellular network.

Project leader Eve Riskin, a professor of electrical engineering at the Seattle school, says the tool is just completing its initial field test by deaf and hard-of-hearing students participating in a summer program.

"This is the first study of how deaf people in the United States use mobile video phones," Riskin said in a statement.

The field test allows the research team to see how people use the device in their daily lives and what obstacles they encounter.

The challenge for researchers has been to deliver enough image quality around the face and hands so sign language could be recognizable but still low-cost, Riskin says.

To extend the phone's battery life during video use, the device employs motion detection to determine whether or not a person is signing.