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Monday, June 23, 2003

BREAKING NEWz you can UzE...
compiled by Jon Stimac

Livescan: More Accurate, Less Messy - THE LONDON DAY, CT - June 21, 2003 ...will this "new" fingerprinting method put ink-and-roll on back burner?

Fingerprint Database Merge Off Schedule - ABC NEWS  - June 20, 2003 ...the FBI and Immigration fingerprint database merge is two years behind schedule...

Mistrial in Murder Case Nearly Three Decades Old - KFOX, TX - June 21, 2003 ...There was evidence at the scene that suggested that it could have been the defendant, there was evidence at the scene that suggested it could have been any number of other people whose prints were never identified...

Thumbprints Used to Tackle Fraud - BBC NEWS, UK - June 17, 2003 ...some UK shoppers are to be asked to provide a thumbprint on checks and credit card transactions in an attempt to tackle fraud...

Good morning via the "Detail," a weekly e-mail newsletter that greets latent print examiners around the globe every Monday morning. The purpose of the Detail is to help keep you informed of the current state of affairs in the latent print community, to provide an avenue to circulate original fingerprint-related articles, and to announce important events as they happen in our field.


Dates to register for the IAI conference in Ottawa are quickly approaching.  The program is going to be excellent, so if you are deciding whether or not to register, go ahead and go for it.  The host hotel is full, but last time I checked the overflow hotel (Les Suites) still had some rooms available.  You can register online at www.theiai.org


Last week, Lee Stonebreaker shared an idea regarding processing thermal paper for latent prints.  This week, I wanted to throw out an interesting conept for discussion.  I have recently been involved in a small validation project which has required the creation of two different databases of latent print images which were as close to the same as possible.  In order to get the best results possible, I came up with a 5-point grading scheme for latent prints that I wanted to run by everyone.  I know this is not by any stretch of the imagination a comprehensive list of factors, but I feel it fairly adequately addresses the major factors involved in how difficult or easy a particular comparison might be. (given standard inked prints to compare)  I am interested in the discussion on the back end of this week's Detail, so if you are reading along and think of something else, or if you have dealt with this issue before and have some thoughts, please drop by the Message Board and share your viewpoints.

The first element was QUANTITY, graded on a scale of 1 to 10.  If the print appeared to be about as large as a latent print from that finger could be, it would get a 9 or 10.  On the other hand, the smallest area of impression possible to identify (0 to 10% of the source), it would get a "1".

The second element was CLARITY, also graded on a scale of 1 to 10.  There is a lot that goes into clarity, but the major factor I was considering was how clear ridge features appeared.  A "1" in this category might be a latent print which was completely out of focus, or possibly just black ridges in a heavy matrix which showed no pore or edge detail at all.  Of course, the opposite end of the spectrum, a "10", would be reserved for the most pristine latent prints, displaying abundant pore and edge detail in very sharp focus.  Naturally, different types of distortion will affect over-all clarity, but the scale takes this into account as a general part of clarity. 

The third element was CONTRAST.  On our same scale, a "1" would go to a print which was barely discernable, while a "10" would be given to a print which displayed a full range of grayscale over the entire ridge system.  This went hand in hand with the next element:

The fourth element was contrast SHIFT.  Some prints displayed about a "5" in terms of contrast, but some were lighter and others were darker, so I created this category to refer specifically to the direction the print shifted from "middle" gray.  A "1" in this category would be print displaying very light ridge detail on a white background, and a "10" would be almost black ridges on a black background.  Of course, a "5" would be a latent print which displayed grayscale ranges approximately half-way between pure white and pure black.

The fifth and final element was SURFACE.  This involved generally how the detail of the image was affected by the background (substrate) noise, but for my study this ended up simply being a distinction between porous and non-porous, for simplicity sake.  Another scale of 1-10 would have probably been too much for the results I was trying to achieve.

So the question is: what do you think?  Did these factors address most of what it would take to grade a latent print?  Would there be anything else you would add to get a significantly more complete picture of a latent print?

Theoretically, a latent print "3,5,3,2,p" would be approximately the same difficulty level as a "3,4,4,3,p" but completely different than a "8,2,6,9,n".  I feel I was able to use these grading codes to pair up prints in two different databases, resulting in two groups of nearly identical difficulty, but containing different images.  I was also able to pick a range of difficulty based on an objective analysis of each print before the selection, avoiding claims that I was seeing more or less of a particular factor because that was what was needed to pair those prints.  Your feedback on the CLPEX
message board would be greatly appreciated: (http://www.clpex.com/phpBB/viewforum.php?f=2)

And as usual, the onin.com forum (http://onin.com/fp/wwwbd/) is also available for more formal latent print-related discussions.

For discussions with an international flair, check out Dave Charlton's forum at: http://charlton97.proboards12.com/index.cgi



The "FFF" folder is empty, so if you find something interesting while you are surfing the net, send it in.


UPDATES on CLPEX.com this week...

No major updates on the site this week.

Feel free to pass The Detail along to other examiners.  This is a free newsletter FOR latent print examiners, BY latent print examiners. There are no copyrights on The Detail, and the website is open for all to visit.

If you have not yet signed up to receive the Weekly Detail in YOUR e-mail inbox, go ahead and join the list now so you don't miss out!  (To join this free e-mail newsletter, send a blank e-mail to: theweeklydetail-subscribe@topica.email-publisher.com )  Members may unsubscribe at any time.  If you have difficulties with the sign-up process or have been inadvertently removed from the list, e-mail me personally at kaseywertheim@aol.com and I will try to work things out.

Until next Monday morning, don't work too hard or too little.

Have a GREAT week!