1 fingerprint sensing techniques, devices and applications rahul singh [email protected] 30 th...

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Fingerprint SensingFingerprint SensingTechniques, Devices and Techniques, Devices and

ApplicationsApplications

Rahul SinghRahul [email protected]@cs.cmu.edu

3030thth April 2003 April 2003

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Fingerprint BiometricFingerprint Biometric

►First used in China in 700 ADFirst used in China in 700 AD►Proposed in Europe in 1858, Proposed in Europe in 1858,

implemented in Germany in 1903.implemented in Germany in 1903.►Unique – So far no two prints from Unique – So far no two prints from

different fingers have been found that different fingers have been found that are identicalare identical

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Fingerprint Biometric Fingerprint Biometric CharacteristicsCharacteristics

► Fingerprint is the representation of the Fingerprint is the representation of the epidermis of a fingerepidermis of a finger

► Set of (almost/often) parallel ridge linesSet of (almost/often) parallel ridge lines► Ridges produce local patternsRidges produce local patterns

Source: http://www.biometrika.it/eng/wp_fingintro.html

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Fingerprint Biometric Fingerprint Biometric CharacteristicsCharacteristics

► Five main classes of Five main classes of fingerprintsfingerprints ArchArch Tented ArchTented Arch Left LoopLeft Loop Right LoopRight Loop WhorlWhorl


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Fingerprint SensingFingerprint Sensing

► Two stagesTwo stages1.1. Capture Fingerprint imageCapture Fingerprint image

2.2. Process image and extract featuresProcess image and extract features

3.3. Store data for comparison or compare Store data for comparison or compare with stored templateswith stored templates

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Types of Fingerprint SensorsTypes of Fingerprint Sensors

► Optic ReflexiveOptic Reflexive Finger lies on a prism. Total internal reflection Finger lies on a prism. Total internal reflection

produces image of fingerprint on a camera chipproduces image of fingerprint on a camera chip

► Optic Transmissive with Fiber Optic PlateOptic Transmissive with Fiber Optic Plate Light source illuminates through the finger Light source illuminates through the finger Finger lies on fiber-optic plate that transmits Finger lies on fiber-optic plate that transmits

image data to camera chipimage data to camera chip

► Optical Line Optical Line Pixel array measures the light reflected by the Pixel array measures the light reflected by the

fingerfinger

Source: http://home.t-online.de/home/manfred.bromba/fpfaqe.htm

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► Capacitive LineCapacitive Line Capacitor array measures the capacitance at each Capacitor array measures the capacitance at each

pixelpixel► Thermal LineThermal Line

Finger is moved across a narrow array of thermal Finger is moved across a narrow array of thermal sensorssensors

Temperature varies across the grooves and ridgesTemperature varies across the grooves and ridges Thermal sensors measure the temperature Thermal sensors measure the temperature

differences over timedifferences over time► Pressure SensitivePressure Sensitive

Sensor measures the pressure per pixelSensor measures the pressure per pixel► Dynamic CapacitiveDynamic Capacitive

Capacitance is measured by A/C voltageCapacitance is measured by A/C voltage


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► Static Capacitive Type 1 Static Capacitive Type 1 One electrode per pixelOne electrode per pixel Capacitance measured w.r.t neighboring pixel.Capacitance measured w.r.t neighboring pixel. If pixel is on a groove capacitance is smallIf pixel is on a groove capacitance is small If pixel is on a ridge then capacitance is largeIf pixel is on a ridge then capacitance is large

► Static Capacitive Type 2Static Capacitive Type 2 Same as above except capacitance is measure Same as above except capacitance is measure

w.r.t groundw.r.t ground► Acoustic (Ultrasound)Acoustic (Ultrasound)

Image of fingerprint is recorded by very high Image of fingerprint is recorded by very high frequency soundfrequency sound


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Capacitive SensingCapacitive Sensing► Fingerprint consists of tightly spaced ridges Fingerprint consists of tightly spaced ridges

and valleysand valleys► Sensor consists of a capacitive arraySensor consists of a capacitive array► Capacitive array acts as one plate of a Capacitive array acts as one plate of a

capacitor while the finger acts as the othercapacitor while the finger acts as the other► Each pixel in the array is charged to a Each pixel in the array is charged to a

reference voltage and allowed to discharge reference voltage and allowed to discharge with a reference currentwith a reference current

► The rate of change of potential at each pixel The rate of change of potential at each pixel is proportional to the capacitance seen by is proportional to the capacitance seen by the arraythe array

dt

dvCiref

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Capacitive SensingCapacitive Sensing

1.1. Charge amp reset. Inverter O/P settles to thresholdCharge amp reset. Inverter O/P settles to threshold

2.2. Ref. charge applied to I/PRef. charge applied to I/P

3.3. O/P Voltage proportional to feedback capacitanceO/P Voltage proportional to feedback capacitance

4.4. Inverter O/P = upper saturation level if there is no feedback capacitanceInverter O/P = upper saturation level if there is no feedback capacitance

5.5. Inverter O/P = close to logical threshold when feedback capacitance is largeInverter O/P = close to logical threshold when feedback capacitance is large

Source: http://www-micro.deis.unibo.it/~tartagni/Finger/FingerSensor.html

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Capacitive SensingCapacitive Sensing

►300 x 300 pixel array (90,000 pixels)300 x 300 pixel array (90,000 pixels)►500 dpi Fingerprint image 500 dpi Fingerprint image

Source: http://www.fme.fujitsu.com/products/biometric/pdf/Find_FPS.pdf

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Optical SensingOptical Sensing

Source: [Tactilesense] http://www.ethentica.com/tactwhtpr.pdf

► Finger touches light emitting TactileSense polymerFinger touches light emitting TactileSense polymer► Photodiode array embedded in the glass detects Photodiode array embedded in the glass detects

illumination illumination ► Image is captured and transferred for storageImage is captured and transferred for storage

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Optical SensingOptical Sensing

► Sensing by projecting Sensing by projecting an image of the an image of the fingerprint onto a fingerprint onto a camera by total camera by total internal reflection.internal reflection.


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Optical Vs CapacitiveOptical Vs Capacitive

► CapacitiveCapacitive Greater miniaturizationGreater miniaturization Newer technologyNewer technology Can be embedded into small devices Can be embedded into small devices Prone to dirt etc since finger touches siliconProne to dirt etc since finger touches silicon Relatively cheapRelatively cheap

► Optical SensorsOptical Sensors Larger sensing area since manufacturing large Larger sensing area since manufacturing large

pure silicon chips is expensivepure silicon chips is expensive More robust. Longer lifeMore robust. Longer life More expensiveMore expensive Better image quality and higher resolutionBetter image quality and higher resolution

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Factors affecting the scanFactors affecting the scan

► Image qualityImage quality SharpnessSharpness ContrastContrast DistortionDistortion

Source: http://www.biometrika.it/eng/wp_scfing.html

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Factors affecting the scanFactors affecting the scan

► Resolution – higher is Resolution – higher is betterbetter Too low and we cannot Too low and we cannot

detect the minutiaedetect the minutiae

► Sensing areaSensing area Average fingerprint is Average fingerprint is

about 0.5” x 0.7”about 0.5” x 0.7” Large area (1.0” x 1.0”) Large area (1.0” x 1.0”)

ensures that overlap ensures that overlap effects (leading to false effects (leading to false rejections) are reducedrejections) are reduced

Source: http://www.biometrika.it/eng/wp_scfing.html

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Data Storage and MatchingData Storage and Matching

►Minutiae or Galton Minutiae or Galton CharacteristicsCharacteristics Termination of Ridge linesTermination of Ridge lines Bifurcation of Ridge linesBifurcation of Ridge lines


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►Final data size = 300 to 600 bytesFinal data size = 300 to 600 bytesSource: http://www.fme.fujitsu.com/products/biometric/pdf/Find_FPS.pdf

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► Directional MapDirectional Map Discrete matrix whose elements denote the Discrete matrix whose elements denote the

orientation of the tangent to ridge linesorientation of the tangent to ridge lines

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FX2000FX2000► FX2000 – Optical FX2000 – Optical

SensorSensor Database of 100 users Database of 100 users

(non-experts)(non-experts) Low quality Low quality

fingerprintsfingerprints

TASK SPEED_DEFAULT SPEED_FAST

Feature extraction 350 ms 260 ms

Matching 120 ms 47 ms

Identity verification (1:1) 470 ms 307 ms

Identification (1:50) 3.35 sec 1.43 sec

Efficiency

Accuracy

threshold t SPEED_DEFAULT SPEED_FAST

FAR FRR FAR FRR

0.3500 0.0049 (0.49%) 0.0005 (0.05%) 0.0032 (0.32%) 0.0009 (0.09%)

0.3750 0.0025 (0.25%) 0.0010 (0.10%) 0.0014 (0.14%) 0.0014 (0.14%)

0.4000 0.0011 (0.11%) 0.0014 (0.14%) 0.0005 (0.05%) 0.0020 (0.20%)

0.4250 0.0006 (0.06%) 0.0019 (0.19%) 0.0002 (0.02%) 0.0034 (0.34%)

0.4500 0.0004 (0.04%) 0.0026 (0.26%) 0.0000 (0.00%) 0.0049 (0.49%)

0.4750 0.0000 (0.00%) 0.0036 (0.36%) 0.0000 (0.00%) 0.0063 (0.63%)

Verification time (1:1)Verification time (1:1)Time to verify the identity Time to verify the identity

Identification time (1:50)Identification time (1:50)

Average time to identify Average time to identify an individual. 50 an individual. 50 Users. Match is Users. Match is found in the middle.found in the middle.

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Secugen FDA01/FCA01Secugen FDA01/FCA01

► Optical sensorOptical sensor► Resolution = 500 Resolution = 500

dpidpi► Verification time = Verification time =

< 1 second< 1 second► Sensing area = Sensing area =

13.6mm x 16.2mm13.6mm x 16.2mm

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Authentec FingerLocAuthentec FingerLoc

► AF-S2AF-S2 CapacitiveCapacitive 68 pin PLCC68 pin PLCC Resolution: 250 dpiResolution: 250 dpi Array Array

size: .512”x.512”size: .512”x.512”► AFS8500AFS8500

CapacitiveCapacitive 144 pin LQFP144 pin LQFP Resolution: 250 dpiResolution: 250 dpi Array Size: .384” Array Size: .384”

x .384”x .384”

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Biomouse/Biomouse plusBiomouse/Biomouse plus

►Optical sensorOptical sensor►““High speed” matching algorithm – High speed” matching algorithm –

400 prints per second on pII 400.400 prints per second on pII 400.►Resolution = 500 dpiResolution = 500 dpi►Average template size = 350 bytesAverage template size = 350 bytes►Biomouse Plus comes with built in Biomouse Plus comes with built in

smart card readersmart card reader

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Defeating Fingerprint Defeating Fingerprint ScannersScanners

►Gummi bears defeat fingerprint sensors Gummi bears defeat fingerprint sensors Japanese cryptographerJapanese cryptographer Gelatin + plastic mouldGelatin + plastic mould Latent fingerprints from glassLatent fingerprints from glass Cyanoacrylate Adhesive (superglue fules)Cyanoacrylate Adhesive (superglue fules) Digital cameraDigital camera Adobe PhotoshopAdobe Photoshop Photosensitive PCB – etched print in copperPhotosensitive PCB – etched print in copper Moulded finger with printMoulded finger with print

Source: http://www.theregister.co.uk/content/55/25300.html

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Defeating Fingerprint Defeating Fingerprint SensorsSensors

►More sophisticated devices use More sophisticated devices use incorporate biosensing modules prior incorporate biosensing modules prior to fingerprint captureto fingerprint capture

►Detect blood flowDetect blood flow►Detect body heatDetect body heat►Sensor shuts down if no life is detectedSensor shuts down if no life is detected

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Types of attackTypes of attack

►Brute forceBrute force►Latent printLatent print►ReplayReplay►Trojan HorsesTrojan Horses►Fake featureFake feature►Dead featureDead feature►Other (software leaks, bad security Other (software leaks, bad security

policies etc)policies etc)

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ApplicationsApplications

►Secure logins via keyboard modulesSecure logins via keyboard modules►User identification at kiosksUser identification at kiosks►Biometric door locksBiometric door locks►Credit card securityCredit card security►Weapon activationWeapon activation►Theft protectionTheft protection

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Fingerprint Verification for Smart Fingerprint Verification for Smart CardsCards

Motorola, AustraliaMotorola, Australia►Senior Honors thesisSenior Honors thesis►Develop biometric security solution Develop biometric security solution

(prototype) for Motorola dual-slot phones(prototype) for Motorola dual-slot phones►Users insert credit card into slot 1 for e-Users insert credit card into slot 1 for e-

commercecommerce►Smart card with embedded biometric Smart card with embedded biometric

into slot 2into slot 2►Fingerprint sensor on phone identifies Fingerprint sensor on phone identifies

user and authorizes use of credit carduser and authorizes use of credit card

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Motorola, AustraliaMotorola, AustraliaEnrollment

Fingerprint template

1010011010100101

X.509 Certificate

Smart Card


1010011010100101

X.509 Certificate

http://www.roma.unisa.edu.au/08216/99u/index.html

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Motorola, AustraliaMotorola, AustraliaVerification


1010011010100101

X.509 Certificate

Smart Card


1010011010100101

X.509 Certificate


1010011010100101


1010011010100101

Compare

http://www.roma.unisa.edu.au/08216/99u/index.html

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1 fingerprint sensing techniques, devices and applications rahul singh [email protected] 30 th...

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