"The bottom line is that digital images are simple, incomplete approximations of the images they attempt to capture," they wrote. The authors encourage courts to take a more skeptical look at fingerprint testimony, recommend that computer systems check as many fingerprints as are available and advise greater scrutiny of the matching criteria embedded in the programs that match fingerprints.
Right on the money
The Cherry-Imwinkelried articles relate to later stages in fingerprint analysis than the Worley MXRF visualization method. More specifically, they address the question of how prints should be recorded after visualization, the limitations of digital images and the criteria that the computer or human examiner uses to make the match or no-match decision.
Imwinkelried believes the entire fingerprinting system is so fraught with unreliability, enhancements at any stage are welcome.
"I applaud an improvement at any stage in the fingerprint process," Imwinkelried says. "Law enforcement and national security depend vitally on the validity of fingerprint analysis, and this research promises an improvement in the earliest stage of the process."
A number of issues remain to be pursued with the Worley method before it's available, not the least of which is designing an X-ray instrument specifically for analyzing fingerprints in the field. The instrument Worley used in the lab for his concept work was built for a variety of material analysis applications and not specifically for fingerprints. It is therefore not optimized for detecting trace levels of chemicals found in some types of prints. Optimization is possible with additional funding.
Douglas Page (firstname.lastname@example.org) is a science and technology writer living in Pine Mountain, California.