IIT Delhi scientists develop superfast laser fingerprint scanner

November 17th, 2007 - 1:50 pm ICT by admin  

London, November 17 (ANI): Two scientists from the Indian Institute of Technology (IIT) in New Delhi have developed a portable device that can scan fingerprints in microseconds.

Satish Kumar Dubey and Dalip Singh Mehta, who developed the device, have revealed that the system works using a technique called optical coherence tomography.

The scientist duo insists that the invention promises to be better than existing fingerprint detection methods because it does not warrant any chemical processing.

This is the first time that optical coherence tomography (OCT), an optical version of ultrasound imaging that is routinely used in medicine, has been endeavoured to be given a forensic application.

The technique provides a transparent three-dimensional picture by sending light though the pattern of natural secretions left on a surface by a finger and combining the reflected beam with a “reference beam” produced by bouncing light from a laser off a mirror.

It produces an interference pattern at a photo-detector, the same as is found in a digital camera, which can then be used to reconstruct an image of the original fingerprint.

The scanner also has a provision for filtering out undesired reflections by using a mathematical approach called selective Fourier filtering. It provides the system with the capability to detect fingerprints from surfaces that do not reflect light well, such as paper.

Conventional techniques require chemical processing to enhance the contrast of fingerprint impressions.

Since the device currently uses a low frame-rate digital camera as its photo-detector, its response time is limited.

“This can be improved using a high speed camera with smaller pixel size, which means the device will have the speed of a few microseconds,” New Scientist magazine quoted Mehta as saying.

Haida Liang of UKs Nottingham Trent University, who is an expert on the technique, said: “OCT is a 3D instrument, hence excellent for the job. The technique reported here is trying to image fingerprints with better sensitivity and clarity. There’s certainly potential in using OCT for fingerprint detection and very little has been done on this application.

The new system has been described in Applied Physics Letters. (ANI)

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