John D. Grantham

Mobile Phone Fingerprinting: A Picture is Worth a Thousand Words

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.

Certification Pathway for Downsampling 1000 ppi Fingerprint Friction Ridge Imagery to 500 ppi

This puication is avilable ree of carge rom : http://dxorg/10.6028/N IT.S P.0-306 The document describes the procedure by which fingerprint image downsampling procedures will be evaluated with respect to conformance to the NIST guidance for sample rate reduction of 1000 ppi1 friction ridge images to 500 ppi as specified in NIST Special Publication 500-289 [NIST3]. This guidance is to be followed whenever 1000 ppi images are to be prepared for comparison to legacy 500 ppi fingerprint databases for submittal to the FBI’s Next Generation identification system and conformance will ensure that CODECs produce encoded files that retain fidelity to the non-compressed source images within empirically set limits and that such files can be decoded by other conformant JPEG 2000 CODECs maintaining the required fidelity. The document describes the attributes of a set of fingerprint images selected for conformance testing and the rationale for selection of these images based on spatial frequency fidelity of downsampled images to non-compressed images scanned at 500 ppi where downsampling is performed using the Gaussian filter with subsampling method specified in NIST SP 500-289. The document describes the procedure to be followed in having an algorithm tested for conformance, the metrics used to measure conformance, and provides instructions on how to run the protocol and submit results to NIST for evaluation.