May 4, 2011


This blog has been a pleasure to write.  As my loyal readers know this blog is a project for my communicating science class and I am sad to say it has come to an end.  After this point no new posts will be written but the blog will remain online for your entertainment. 

I have learned a lot from this blogging experience and I thank all of you who read my blog and especially those who commented.  Don’t hesitate to contact me via the contact widget on the bottom right.
So long and thanks for all the fish!


May 3, 2011

Angels & Demons

Angels & Demons is a great book written by Dan Brown that is full of suspense and mystery.  In 2009 a film adaptation of the book was made starring Tom Hanks as Robert Langdon, a Harvard symbologist.

But while the book and the movie are entertaining they are full of inaccuracies.  That is why I got the idea to write about the inaccuracies from J.D.’s blog Science in Fiction.  J.D. is no stranger to pointing out inaccuracies in Angels & Demons, since she already has in her post Angels +Demons + Science. Go check it out!

But seeing as this is a biometrics blog I will post on the inaccuracy in biometrics on Angels & Demons, particularly their use of a retinal scanner.  

The Prologue to the book is a grim scene where an intruder brands Physicist Leonardo Vetra and “The figure produced a blade and brought it to Vetra’s face. The blade hovered. Carefully. Surgically.”  You find out later in the book that Vetra’s eye was “stolen” during his murder.  

Once Langdon makes it down to Vetra’s laboratory deep underground, they find that the laboratory is locked with a retinal scanner.  Langdon realizes why the eye was stolen and looks below the scanner at a couple drops of blood.  Further in to the laboratory there is another retinal scanner where this time on the floor they find Vetra’s eye in all its hazel colored glory.

So the question then is: Is it possible to remove an eye and use it for a retinal scanner? And the answer is very obviously no.  

There is a reason I called Retinal scanners the King of Biometrics, since fooling the scanner would be incredibly hard.  As far as taking the eye from Vetra and using it on the scanners there are a few reasons why this simply could not work.

First of all, soon after you die all of the blood drains from your retina and thus there is no pattern to recognize.  You might be inclined to point out that the prologue suggests that Vetra is still alive when his eye is removed and you would be correct.  But even given that he was alive when his eye was removed the retina would be ruined if not preserved in a perfect way.  

Consider the retina as a thin piece of tissue paper lining the surface of a sink full of water.  When the water is moved the retina would detach and thus ruin it for scanning.  In a younger person the sink would be full of a material with a consistency closer to jello.  However in the book it mentions that Vetra is elderly and thus his retina would be very fragile.  

Secondly even if somehow the killer could remove the eye perfectly without ruining the retina, he could never use it on the scanner.  As you loyal readers know, retinal scanning requires the subject to focus on a green light that they observe in the scanner.  This simply could not be done with a detached eye. 

Thus in a fully accurate world, the killer would never have gotten access to the top secret lab and would have never have stolen the anti-matter therefore the entire scenario could have been avoided.
But don’t be such a scientist! Even though the book has a lot of inaccuracies it still tells a good story and I recommend you read it, or watch the movie.  Just try to hold back yelling at the screen now that you know the truth :)

Source: James Carlisle. Eyeball to Eyeball: The use of Biometrics in Angels & Demons.

May 2, 2011

We Got Him!

So as all of you have undoubtedly heard by now on Sunday morning a squad created by JSOC or Joint Special Operations Command infiltrated Osama Bin Laden’s one acre hiding facility and was able to terminate Bin Laden with two shots to the head.  What might not be so clear and won’t be for a long, long time is how the intelligence leading up to knowing his location was obtained.  

One thing that is known however is that JSOC units were paired with intelligence analysts from the NSA, CIA and the NGA.  The technicians could “exploit and analyze” data obtained instantly from the battlefield including biometric and facial recognition data. Sound familiar? It should if you are a dedicated reader of my blog, since this data was most likely gathered by using the HIIDE device that I talked about in Biometric Army.  

So while the intelligence information will be classified for a loooong time, I am happy to think that biometrics might have helped in some way to locate Osama. 

May 1, 2011

Minutiae reduction

Fingerprint use is as old as time itself.  Fingerprints have been found on Babylonian tablets seals and pottery dating back to the second millennium BCE.  By around 246 BCE Chinese officials were using fingerprints to seal documents.  Whether they yet knew that no two fingerprints are alike is not fully known but the records show that they did use fingerprints as a means of identification.  By 650 AD a Chinese historian mentioned that fingerprints could be used as a means of identification.  For more information see Wikipedia

The first modern version of a fingerprint database was created in 1892 in Argentina, and by use of fingerprints they were able to have a murderer confess to her murders.  Fingerprints were then used extensively by being imprinted on paper which is still used today in some places.  

Fingerprint recognition involves the basic matching of three major features: the whorl, the arch and the loop.  These features are distinguishable with the human eye and provide a general sense for fingerprint identification.  To really get into the detail however you need to observe the minutiae.  
Whorl Pattern
Loop Pattern

The most important characteristic of fingerprints are the minutiae, which is just a fancy word for fingerprint ridges at a local (small) scale.  When fingerprints are imprinted on paper and scanned inaccuracies can arise based on the entire procedure.

One thing that can reduce accuracy of fingerprint scanning is the accidental addition/ removal of minutiae.  This problem can occur for several different reasons including smudges or noisy regions, image contrast, or overall image quality.

Research has been done into how to create an algorithm (sequence of steps) to eliminate false minutiae or to add back in minutiae that were lost in the scan.  This research was very effective reducing the amount of false minutiae by about 40% as opposed to the crossing number method of extraction.

This improvement in the reduction of errors comes from the algorithm that the researchers developed.  This algorithm involves several steps for the processing after the scan that is the cause for the reduction of error. 

You may be wondering: Why should I care about an algorithm that scans fingerprints from paper when all fingerprints are now being scanned digitally? Good question, and the answer is that while yes, most scanning now occurs digitally, there are still lots of fingerprints that are on paper and not in digital form.  This article is relatively young being released in 2008, so it is still relevant.
Source: M.U. Akram et al. Fingerprint image: pre- and post- processing.  International journal of Biometrics. Volume 1 (2008).