Mobile Phone Fingerprinting: A Picture is Worth a Thousand Words

Abstract

The United States Department of Homeland Security (DHS) relies on the use of biometrics as an important component of its mission to keep America safe. Risks are involved with the current systems that use contact fingerprint technology such as the transmission of pathogens by contacting the scanner. Touchless systems address this risk but also introduce new challenges. Sixty National Institute of Standards and Technology (NIST) employees participated in the study to determine the usability of three mobile phone devices as well as the image quality of the resulting fingerprint images. All participants had previous experience with capturing their prints using a contact device and as a result tried to touch the screen on the mobile phone to capture their fingerprints. All the participants had mobile phones and were aware of the phone’s features including a camera and capture process for the mobile phone devices involved using the phone’s camera to take a photo of fingerprints. We believe that participants did not equate the capture process to taking a photo of their fingers and were using an existing mental model for capturing their fingerprints and as a result they touched the phone’s glass screen. The devices provided little if any or often somewhat confusing instructions to assist the user and little if any feedback regarding the success of the capture. To study the image quality of the prints, we assisted the participants in collecting a set of prints using both the mobile phone devices and the contact field devices. We compared the image quality and the interoperability of the contactless captures with the legacy contact captures. Currently the image quality and interoperability is less than desirable.