Ridgeology

fingerprint minutiae

1. A Closer Look at Fingerprints
Image from ftp://sequoyah.nist.gov/pub/nist_internal_reports/ir_6534.pdf T. Trimpe 2007 http://sciencespot.net/

2. Ridgeology:Thestudyoftheuniquenessoffrictionridgestructures
andtheiruseforpersonalidentification.
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1
Introduction to Basic Ridgeologyby David Ashbaugh, May 1999 Image from http://www.cs.usyd.edu.au/~irena/minutia.gif
Thekoalaisoneofthefewmammals(otherthanprimates)that
hasfingerprints.Infact,koalafingerprintsareremarkablysimilar
tohumanfingerprints;evenwithanelectronmicroscope,itcan
bequitedifficulttodistinguishbetweenthetwo.
Aswehavelearnedinourfirstlesson,a
fingerprintismadeofaseriesofridgesand
valleysonthesurfaceofthefinger.The
uniquenessofafingerprintcanbedeterminedby
thepatternofridgesandvalleysaswellasthe
minutiaepoints,whicharepointswheretheridge
structurechanges.

3. FingerprintIdentification
Whenminutiaeontwodifferentprintsmatch,thesearecalled
pointsofsimilarityorpointsofidentification.Atthispointthere
isnointernationalstandardforthenumberofpointsof
identificationrequiredforamatchbetweentwofingerprints.
However,theUnitedKingdomrequiresaminimumsixteenpoints
whileAustraliarequirestwelve.InU.S.courts8-12pointsof
identificationaregenerallyrequired.
Automated Fingerprint Identification System(AFIS)
http://www.fdle.state.fl.us/CrimeLab/images/fingerrint%20comparison%20for%20afis.jpg
AFISisacomputerizedsystemcapableofreading,
classifying,matching,andstoringfingerprintsfor
criminaljusticeagencies.Qualitylatentfingerprints
areenteredintotheAFISforasearchforpossible
matchesagainstthestatemaintaineddatabasesfor
fingerprintrecordstohelpestablishtheidentityof
unknowndeceasedpersonsorsuspectsinacriminal
case.
AFIS Video Link:
https://www.youtube.com/watch?v=ZKi1CKTRCQM

4. Ridge Characteristics
Use these characteristics as points of identification when comparing fingerprint
samples. The more points you can find in common, the better the match!

5. http://cnx.org/content/m12574/latest/properties.jpg
Ridge Characteristics
Crossover
Core
Bifurcation (fork)
Ridge ending
Island
Delta
Pore
Scar

6. http://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpg
How many ridge characteristics can you identify in this fingerprint?

7. 1–Blowupyourballoonabouthalfwayandtwisttheendtokeepthe
airfromcomingout.Donottieitoff!
2–Useaninkpadtomakeaprintwithallofyourfingersandlabel
eachonewithapermanentmarker.Writeyournameontheballoonas
well.
3–Blowuptheballoontofullsizeandtietheend.
4–Analyzethefingerprintstofindseveralridgestructuresthatwe
havediscussed.Useahighlightertomarkthesestructuresonyour“My
Prints”worksheet.
Try It!
Think About It!
Which ridge structures were most common in your fingerprints?
Which ridge structures were most common in your group?
Were there any structures that were not found in any of the fingerprints?
Balloon Fingerprint Activity: http://www.msichicago.org/fileadmin/Education/learninglabs/lab_downloads/fingerprint_analysis.pdf