3D "Digit" Image Capture - A Better Fingerprint ID

FlashScan3D along with its research partner, the University of Kentucky, received a grant from the Science and Technology Directorate of the U.S. Department of Homeland Security to develop non-contact fingerprint. Image Credit: FlashScan3D

3D "Digit" Image Capture - A Better Fingerprint ID

A new way to capture an image of a human fingerprint has emerged from the labs of the University of Kentucky. The University has been a leader in research in the use of structured light and its application to biometrics.

Within the law enforcement community, the preferred form of fingerprint is the “rolled” or “rolled equivalent” fingerprint. Image Credit: FlashScan3D

In partnership with a for-profit private company, FlashScan3D, the University of Kentucky has developed a non-contact, rolled equivalent scanner that capture 3-dimensional data of fingerprints and palm prints. No ink, and no potential for error due to a sloppy imprint process.

Structured light illumination's (SLI) core technology revolves around the use of projecting a known pattern of pixels (often grids or horizontal bars) on to a scene. The way that these deform when striking surfaces allows vision systems to calculate the depth and surface information of the objects in the scene enabling the scanner to capture 3-D fingerprint data and provide an accurate representation that far surpasses any other imaging technique.

So, Structured Light makes quantitative 3-D surface measurements that reveal actual ridge shape and depth. It is precisely this 3-D structure that gives a fingerprint its unique latent print characteristics and allows for the formation of minutiae. Capturing this data in 3-D allows for a more accurate representation of the true object, rather than a 2-D representation of a 3-D object, and ultimately yields more accurate data.

The 3D fingerprinting device works by projecting a series of striped lines wrapped around the finger. The process is called structured light illumination (SLI). The image of the lines of the fingers is then perfectly captured by a 1.4 megapixel camera at roughly 1,000 pixels per inch, thus automatically producing a detailed 3-dimensional model of the fingerprint ridges and valleys in proper places [ctrl-click to view animated image]. Image Credit: LiveScan3D

This excerpted and edited from LiveScan3D -

Features & Benefits

Speed of Capture:
FlashScan3D's device captures a rolled equivalent fingerprint in less than 1 seconds with no operator manipulation of the subject’s hand. This feature allows the device to be used in operations with significant time constraints or high volume locations such as airports or security checkpoints where capturing rolled equivalent prints would have been impossible in the past due to the operational constraints of the current generation of rolled equivalent scanners.

Image capture in a field application. Image Credit: FlashScan3D

3-D Data:
The unique characteristic of our system is that it is able to capture fingerprint data in 3-D. Unlike competing systems that acquire an image of what a fingerprint looks like, our system makes quantitative 3-D surface measurements that reveal actual ridge shape and depth. It is precisely this 3-D structure that gives a fingerprint its unique latent print characteristics and allows for the formation of minutiae. Capturing this data in 3-D allows for a more accurate representation of the true object , rather than a 2-D representation of a 3-D object, and ultimately yields more accurate data.

As fingerprint databases continue to grow exponentially both in the U.S. and abroad, more accurate data and matching will become increasingly necessary to aid in searches and correct identification of subjects.

10 Print Capture - FlashScan3D's non-contact 3-D technology captures 10 rolled equivalent prints plus 2 palm prints.Image Credit: FlashScan3D

Backwards Compatible:
Although our device captures data in 3-D, our flattening algorithm ensure that the device outputs data that is formatted to meet the ANSI/NIST ITL 1-2000 standard making it easily compared to and consistent with existing fingerprint databases. Data can be captured and stored in 3-D, while still being able to leverage the size and pervasiveness of existing 2-D databases or for latent print comparison.Flashscan could greatly increase airline safety

Non-Contact:
Using a Structured Light Illumination technique, which is an inherently non-contact scanning method, we are able to produce higher quality images with better minutiae detection results since there is no contact with the scanner to distort the image. Our images are more consistent and repeatable since there are no varying amounts of pressure when in contact with the sensor. In high volume environments a non-contact scanner is advantageous because there are no latent prints or residue left on the scanner that need to be cleaned or could generate noise for subsequent scans. Since contact with the imaging sensor is not required, it allows the device to be completely sealed, preventing dirt, sand or dust from impacting the scanner.

Automated:
Our device is designed to function independently of an operator. The subject simply positions their finger above the sensor and the system to captures the fingerprint. The quality of the print is no longer tied to the skill of the operator manipulating the subject’s hand as is the case today. This feature reduces training and staffing costs, eliminate any possibility for operator error, as well as produces a more consistent, high quality print. The fact that the device is automated also opens up the possibility to use the system for unattended access control.

Flashscan yields better treatment of worn or damaged printsBetter Treatment of Damaged or Worn Prints: A combination of our 3-D and non-contact imaging technique yields better treatment of worn or damaged prints. Within the realm of non-contact print capture, structured light techniques have the advantage of capturing the surface independent of how smooth it is.

Go/No Go – Real Time Quality Assessment:
Our system provides immediate feedback to the subject/operator as to the quality of the captured fingerprints. If something goes wrong with the scan, the subject is notified to re-scan. This real time quality assessment feature helps reduce the failure to enroll rates due to images of poor quality.

Self Calibrating:
To ensure that the image sensors stay calibrated we position a calibration pattern in the scanner, such that the cameras can automatically calibrate themselves prior to each scan, preventing performance drift and eliminating any need for manual calibration. In the event the device becomes damaged or is in some way incapable of calibrating itself, the system will alert the operator with a visual indicator.

Impervious to Sweat/Oil: Our structured light imaging technique is not affected by discolorations in the skin and is resistant to the specularity produced by shiny surfaces caused by sweat or oil.

Liveness detection/Built-in Anti Spoofing Capabilities:
A 3-D system is inherently much harder to fool by deceptive means simply because it is much harder to re-create the 3-D characteristics of a fingerprint using a dummy or fake finger. Because we capture data in 3-D we can test for curvature and ridge modulation to prevent the use of a simple flat photographic pattern.
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