Farewell

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!

-Carlos

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.

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. 

Source

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

Arch

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).

Iris vs. Retina

I have already introduced you to retinal scanning in my previous post The King of Biometrics.  However retinal scanning has a younger more lighthearted brother: the iris scan.  

To most people scanning of the eye is all the same and people constantly mix up the terms iris and retina scans (even the U.S. Army did it see Biometric Army), my hope is that after reading this post you will never make the same mistake.  

So let’s start by defining what an iris is as compared to the retina.  I found a picture that is a good representation of this.  If you look at someone’s eye, the colored section you see is the iris.  That is what is scanned using an iris scanner.  Behind someone’s eye is the retina, and this cannot be seen with the naked eye.  That is why retinal scanners use IR rays in order to generate an image of the retina.

Now you know the major difference between the two technologies.  However I am not going to stop there.  I will tell you how you can easily distinguish between the two technologies if you saw someone using them. 

A retinal scanner is considered more intrusive and is also slower.  For a retinal scan the subject’s eye generally has to be within 3 inches of the scanner and the subject has to focus on a point of green light that he/she would see in the scanner.  The retinal scanner scans about 400 reference points that it uses for identification processes and it takes about twenty seconds.  

As compared to the retinal scanner an iris scanner is a lot faster taking only about two seconds.  The iris scanner can be used from a much farther distance of up to two feet and uses about 240 reference point.  

So basically if the scan is taken at a very short distance and if the scan takes a little while then it is a retinal scan, and if it is done at a longer distance and is instantaneous then it is an iris scan.  Now hopefully you will never make the mistake of misidentifying the two technologies. 

Iris scan sounds better doesn’t it? It is faster and cheaper but also less accurate.  As I described in King of Biometrics retinal scanners are basically foolproof, which leads to an interesting post that is coming up (stay tuned).

Nowhere to HIIDE

Last Post I talked about the HIIDE device being used in Afghanistan and I was able to find a video that shows it in use.

Biometric Army

You’ve seen it done in movies a thousand times, the bad/good guy steals an identity badge and gains access to an installation and wreaks havoc/saves the day.  How can such a thing be stopped? Biometrics of course! And this is exactly what the Army thought as well.

Currently in use in operations Enduring Freedom and Iraqi Freedom is the Hand Held Interagency Identity Detection Equipment or HIIDE for short.  According to the Army this system is used for a lot of different uses and has given great results, and it better have seeing as the Army gave a $71 million dollar contract to the manufacturer.  

HIIDE in Action in Iraq

One example of how this program has helped was given by the Army and boy is it impressive.

Every day hundreds of people access U.S. military facilities; most are U.S. Army personnel, but some are employees of local contractors.  And before these employees can enter they are biometrically scanned for fingerprints, iris and facial recognition.  Today an employee comes to work as normal but one thing very different happens, he is detained for questioning instead of getting to work.  How did this happen? Let’s look back one day. 

The Army received intelligence of a suspected insurgent safe house that was immediately raided by a U.S. Army patrol.  All of the family members were evacuated and their fingerprints, irises, and faces were scanned using the HIIDE, while the house was searched.  Everything in the house appeared normal until the patrol discovered a hidden room with evidence of bomb making activity.  The family was questioned about it and everyone claimed they had no knowledge of the hidden room. 

Unfortunately for one of the “family” members, two sets of fingerprints were found in the hidden room and one belonged to one of the detained “family” members.  As soon as the insurgent was removed from the rest of the family, they tell the Army interrogators that two insurgents were using the room and threatened to kill them if they said anything.  And now one insurgent was in custody.  But what about the other one? Remember that employee that was detained?

Since the employee had access to a U.S. military facility, his fingerprints were in the database and were quickly matched with those scanned at the bomb making site and thus he was detained the next time he went to work. 

That is a major situation avoided by use of biometrics.  It’s great that the Army recognized the value of Biometrics and started using them to ensure the safety of their bases and installations.  

Quick side note: the site where I found the image states “Sgt. Nike Ferzacca is obtaining a retinal scan of an Iraqi.”  See anything wrong with that statement? I mentioned that the HIIDE has iris scanning not retinal scanning.  It is interesting to see that even on “The Official Homepage of the United States Army” they make a mistake between iris and retinal scanners.  The distinction between the two will be addressed in the future, so you never make the same mistake.

Source

The King of Biometrics

There is an old English proverb that states “You get what you pay for,” and this is definitely true of Biometrics.  Biometrics includes many technologies from fingerprint scans, to voice recognition, to facial recognition, but none are as reliable and foolproof as the Retina Scan.

Quick disclaimer here, the retina scan is not to be confused with the iris scan, although both scan they eye they are very different and this will be the subject of a future post.

So the retina scanner like the name implies scans your retina.  But what is your retina? I’m glad you asked.  Retina is just a fancy name for the light-sensitive tissue that lines the inner surface of the eye.  This tissue required blood to function properly and thus has an intricate blood vessels system that is called the choroidal vasculature.  This vasculature is what is scanned by a retina scanner.  

Take a look at the picture below.  The part on the left is a cross section of an eye with the retina being what you can see the blood vessels on.  The ring that you see in the picture is what is scanned by a retina scanner.  This ring can be seen more clearly on the right image which is just a cross section of the eye straight up and down.  Everyone has a unique blood vessel pattern and thus it is perfect for biometrics.

Cool, so now we know what a retina scanner scans, but how does it do it? The actual scanning process is very complicated but I will try to give you a basic run down of how it works.  Take a look at the following image and don’t freak out, a lot of things are pointed out that are not important to us so just ignore them and pay attention to what I circled in blue that I will talk about.

For simplicity the red arrows you see are how the light would travel from the source through the scanner disk and back to the detector.   

So basically, the eye of the person being scanned would be on the left facing inward.  That person would look into the camera and would focus on what would look like a pinhole illuminated by a krypton bulb (1).  The scanner disk (2) would begin to rotate, creating an infrared (IR, high wavelength non-visible light) scanning beam.  The IR beam would be reflected by the choroidal vasculature on the retina to a beam splitter (3) and into a detector (4) that generates the image of the retina.

That is basically how a retina scanner works.  The biggest drawback to this technology is that certain diseases can affect your choroidal vasculature, thus causing you to not be authenticated by the scanner.  This is also a reason your eye doctor can detect a disease just by looking at your eye. 

So that is how the king of Biometrics works.  Retina scanning is the most accurate but also the most expensive biometric security tool.  

Source: Robert Hill. Retina Identification. Michigan State University. 2005.

Fetal Fingerprints (Continued)

Benito el Jefe, one of my awesome commenters posed an interesting question on my original Fetal Fingerprints post. The question was:

“To find out when they develop, did researchers have to look at miscarriages for signs of fingerprint development? How could they determine that otherwise, without possibly harming the child?”

I looked through the articles that were referenced and sure enough one of them mentions how they obtained the information. And Benito was actually spot on.  In the study they investigate 24 aborted or miscarriage human fetuses at different stages of development and they categorize how their fingerprints develop.  These technical name for these fetuses is abortuses.   

This type of study is under a field called Fetal Dermatoglyphics that basically studies how skin develops on fetuses. 

Thanks a lot for the question Benito and everyone keep them coming!

Source: Katznelson, Goldman. Fetal Dermatoglyphics.   

iPhone eyeD App Review

Here is a video I made reviewing a new app available for iPhone 4. Enjoy!

 

 Thanks a lot to my friend Matt Emmett for executive producing this video and lending me his iPhone.

Fetal Fingerprints

Ever wonder how fingerprints develop or why they are all different?  A couple of commenters on my blog did which got me researching the topic.  After looking through a lot of information on how and when fingerprints develop, I finally found a reputable source.  So without further ado I present to you how and when fingerprints develop.

A working theory of how they formed was developed by two scientist at the University of Arizona named Kucken and Newell.  They basically developed their theory by the use of springs.  

As some of you may know the skin has many layers.  It starts with the epidermis and works down to the dermis and others further down, but for the purposes of fingerprints only the top two layers are important.  The epidermis then has a lower layer (basal layer) and an upper layer.

For the model the scientists assumed that the basal layer of skin was an overdamped elastic sheet trapped between the upper epidermis layer and the lower dermis layer.  What this basically means is that the basal epidermis layer can be thought of as a sheet of plastic that does not oscillate (move up and down) much.     

As the basal layer grows, it is stressed (pushed on) by forces from the upper layer of the epidermis, the dermis, and also by inward pressure from the basal layer itself.  This phenomenon can be modeled by terms of elasticity (how much it can stress), and the solution the scientists found is actually the relatively well known von Karman equations.  Once the stress becomes too much, the basal layer “buckles” and produces the ridges in the epidermis that become your fingerprints.

Using the developed equation it was found that fingerprints develop starting in the nail furrow (top portion of the finger), and in the center of the volar pad (center of finger). These then stretch out until the entire finger is covered in fingerprints.  

The main reason everyone’s fingerprints are unique is that everyone had different stresses applied to their basal layer during fetal growth.  Everything from the orientation the fetus is in to the amount of movement the fetus experiences helps differentiate fingerprints.  Even identical twins grow in different orientations and experience different stresses, thus they have different fingerprints.  

Finally, when do the fingerprints develop? Surprisingly early in the fetal development process; fingerprints begin to develop at around the 10^th week of pregnancy and they are set in stone by the 17^th week of pregnancy.  That means that about four months into pregnancy the baby already has defined fingerprints that will be the same throughout their lifetime.  

I find this information to be fascinating and more proof of how amazing the human body is.  Did you know that fingerprints developed so early in the stages of pregnancy? That was shocking to me since I thought fingerprints would be one of the last things to develop.  Let me know if you have any questions and I will try to answer them as well as I can!   

Source:

M. Kucken, A. Newell. A model for fingerprint formation. Europhysics Letters. October 2004. Link