Operating Principles for Very small fingerprint sensors

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Operating Principles for Very small fingerprint
sensors
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Progress in low-cost sensor systems

• The first step is the movement from
• Modular sensor devices ? silicon integrated
  sensor devices
• Cost is now driven by silicon size
• The second step is a new generation of very small
  devices
• Small touch sensors
• Small slide sensors

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An example of a very small touch sensor
Size of active sensing area
AuthenTec AES-3500 small touch sensor
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How do small touch sensors work

• Acquiring enough repeatable information to match
  accurately
• Use the higher density small-scale feature
  information captured in high quality TruePrint
  images to perform matching using less skin area
• Allowing flexible finger positioning on the
  sensor
• Use template compositing to store areas of finger
  skin larger than the sensor itself

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High Resolution TruePrint Imaging
AuthenTecs very small touch sensors can capture
highly detailed images with excellent
repeatably. This image is from an AES-3500
sensor running experimental high resolution
control software.
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High Resolution TruePrint Imaging
A topographic analysis program highlights some of
the detail that can be extracted from the image.
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Flexible finger positioning using a composite
template concept illustration

• Multiple touches during the enroll process
• Are logically interconnected
• Into a larger composite template

Single touch images
Composite template
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What information can be contained in a composite
template?

• Template is
• Several views of a finger
• Location of each view relative to others
• Image and/or feature data for each view

Image representation Pattern representation Featur
e (minutia) data Other data

• Relative location
• Confidence

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Verification using a composite template

• Conceptually
• Compare live view against each template view
• Final score is statistical combination of all
  evaluations

Template
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How do small slide sensors work

• Acquiring enough repeatable information to match
  accurately
• Slide the finger across the sensor
• Capture a stream of small image slices
• Allowing flexible finger positioning on the
  sensor
• Same sliding usage method allows flexible finger
  positioning

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Slide sensor operation
Slide sensors are required where lowest cost is
paramount.
slide
User slides the finger across the sensor
Sensor
Stream of image slices
Small local processor
Match or non-match
Template
Inexpensive devices usually have small processors.
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Slide sensor processing options
Stitched image segments
Sensor
Finger movement
Matching Options

Increasing processor load
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Comparison of small sensors
Sensor Cost Ease of use Typical biometric accuracy Front panel footprint Interface bandwidth needed
Small touch sensor Very low Best Best Small Low
Small slide sensor Lowest Good Good Smallest High
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For more information
Click here to learn about fingerprint Matching
methods
Click here to learn about Specifying commercial
biometric systems
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