Computer programs improve fingerprint grading

July 03, 2013

Subjectivity is problematic when evaluating fingerprints, and quality is in the eye of the examiner. But three computer programs used together can give fingerprint grading unprecedented consistency and objectivity, according to Penn State researchers.

"People leave behind all kinds of fingerprints, and the job of a forensic examiner is then to look at a fingerprint and identify a person who could have left it," said Akhlesh Lakhtakia, Charles Godfrey Binder Professor of Engineering Science and Mechanics, Penn State. "Various scenarios can be envisioned where a fingerprint can be seriously altered. Once it is altered, it can conceivably lead the examiner to a false conclusion."

Fingerprints usually undergo environmental weathering and smudging. The condition of a fingerprint affects how reliable a match can be between a collected print and prints on record. Knowing a fingerprint's dependability can minimize the chance of a wrongful or delayed conviction.

Lakhtakia's team created a process using three inexpensive computer programs to grade a fingerprint for the availability of ridge detail for subsequent identification. Computerized grading ensures standardized evaluation to a degree finer than any human can accomplish. They report their results in the current issue of Forensic Science International.

"The quality of a fingerprint can be graded finer than on a zero, one, two, three scale," Lakhtakia explained. "Two point three per cent is worse than fifteen per cent, but both could be graded as a zero by the naked eye. Humans can't grade finer than the zero to three scale. But computers can."

The three separate computer programs include the FBI's Universal Latent Workstation -- usually free to qualified agencies, the open-source image editor GIMP and a simple custom program written in Mathematica to count pixels.

Investigators photograph the fingerprint--developed for visualization or not--and run the picture through the Universal Latent Workstation. This program creates a simplified map of the fingerprint by designating colors to four area types. The background area is black, areas with definite ridges are white, and debatable regions are yellow and blue.

The GIMP editor converts the map file into an image file with red-green-blue color values. The RGB values are stored as number clusters that a computer program can easily translate into binary sequences useable in a mathematical equation.

A pixel-counting algorithm in Mathematica calculates the total percentage of white pixels from imported RGB pictures, essentially creating a grading scale ranging from 0 to 100. A high-quality fingerprint would have a high number of white pixels, while a potentially unreliable print would mostly appear in yellow and blue.

The ease and relative speed of this grading system may help to standardize fingerprint quality assessment in an inexpensive, efficient manner.

"The next step of this kind of research is, is there false detail created by development techniques?" Lakhtakia said. "That can happen. Looking at the thin-film technique that my group has developed, I don't imagine so, but we would obviously have to prove it."
-end-
Other researchers from Penn State on this project include Drew Pulsifer, graduate student in engineering science and mechanics; Sarah Muhlberger, fingerprint technician; Stephanie Williams, recent graduate in forensic science; and Robert Shaler, retired professor of forensic science.

The U.S. Department of Justice funded this research.

Penn State

Related Fingerprint Articles from Brightsurf:

Shared protein fingerprint could simplify treatment of common inherited heart disease
University of Wisconsin-Madison scientists discovered that many different genetic mutations result in surprisingly similar changes to heart muscle proteins in patients with the most severe manifestations of hypertrophic cardiomyopathy.

Each human gut has a viral 'fingerprint'
Each person's gut virus composition is as unique as a fingerprint, according to the first study to assemble a comprehensive database of viral populations in the human digestive system.

Atomic fingerprint identifies emission sources of uranium
Depending on whether uranium is released by the civil nuclear industry or as fallout from nuclear weapon tests, the ratio of the two anthropogenic, i.e. man-made, uranium isotopes 233U and 236U varies.

Prostate cancer 'fingerprint' detected in blood sample
Scientists at UCL have invented a new test to identify the earliest genetic changes of prostate cancer in blood: a process which could allow doctors to see if cancers have spread, monitor tumor behavior and enable better treatment selection.

Experimental fingerprint test can distinguish between those who have taken or handled cocaine
An experimental fingerprint detection approach can identify traces of cocaine on human skin, even after someone has washed their hands -- and the test is also smart enough to tell whether an individual has actually consumed the class A drug, or simply handled it.

OU study finds the fingerprint of paddy rice in atmospheric methane concentration dynamics
A University of Oklahoma-led study shows that paddy rice (both area and plant growth) is significantly related to the spatial-temporal dynamics of atmospheric methane concentration in monsoon Asia, where 87% of paddy rice fields are situated in the world.

Fingerprint test can distinguish between those who have taken or handled heroin
A state-of-the-art fingerprint detection technology can identify traces of heroin on human skin, even after someone has washed their hands -- and it is also smart enough to tell whether an individual has used the drug or shaken hands with someone who has handled it.

A precise chemical fingerprint of the Amazon
This novel drone-based chemical monitoring system tracks the health of the Amazon in the face of global climate change and human-caused deforestation and burning.

Canadian astronomers determine Earth's fingerprint
Two McGill University astronomers have assembled a 'fingerprint' for Earth, which could be used to identify a planet beyond our Solar System capable of supporting life.

Fingerprint of sleep habits as warning sign for heart disease
Chronic short sleep is associated with increased risk of clogged arteries, heart disease, and thus increased morbidity and mortality.

Read More: Fingerprint News and Fingerprint Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.