Engineering Inside:

2012 Issue 1
Crime Scene Investigation

Try Your Hand at Biometrics!

January 2012

BiometricsHave you ever wanted to solve a crime, or do detective work? There are many ways to get involved in sleuthing!  One way is to explore some of the methods and technologies used by the experts who are trying to solve a crime. For example biometrics is now used in many areas to help identify a unique person by examining one or more of their physical or behavioral traits. There are two main types of biometric identifiers: physiological and behavioral. Examples of physiological characteristics include fingerprints, face recognition, DNA, palm print, hand geometry, and even iris recognition.  How a person walks and the changes in their voice patterns are examples of behavioral characteristics.

Try Hand Geometry Biometrics at Home

Hand geometry is a biometric that identifies users by the shape of their hands. Hand geometry identification devices have been available since the early 1980s, making hand geometry the first biometric to find widespread computerized use! Hand geometry is very reliable when combined with other forms of identification, such as ID cards or personal identification numbers.

Here’s how it works:

The shape of your hand is somewhat unique, and by tracing your hand’s shape and comparing it with others, you’ll find that in a small group of people, yours is probably unique. The shape of the hand really isn’t as unique as fingerprints or retinas, but it can be useful as another layer of security, or to keep track of a time when someone arrives at work or school. Why not find out your own personal hand geometry code!

Step One:
1. Trace your right hand on a piece of paper, keeping the pencil as close to your skin as possible.

2. Using a ruler, measure the following in centimeters (see diagram below):

A: Distance from index fingertip to bottom knuckle ________cm

B: Width of ring finger, measured across the top knuckle _______c

C: Width of palm across 4 bottom knuckles ________cm

D: Width of palm from middle knuckle of thumb across hand _______cm

How to measure your hand

Record the 4 numbers in A, B, C, D order, which is your personal hand geometry code.

ExampleStep Two:
Compare your personal hand geometry code with the one to the right which has the code  8, 2, 9, 12, and consider the questions below.  Or, work with family or friends to see what their code is – how does it differ from your own?


1. How does your hand differ from the sample hand geometric image?  Do you think you could access their office through a security system using your hand?
2. How does your hand differ from those of your friends or family members?
3. Do you think that hand geometry would need to be recalculated every few years or as a person grows older?

(Note: Some biometric information in this article is provided by and used with the permission of The National Biometric Security Project (NBSP).  Duplication is permitted for educational purposes only.)

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