MOTOROLA
MCF5249 Fingerprint Security Reference Design User’s Guide
7
3.2
Verification Mode
In verification mode, the user’s fingerprint is captured and compared against the template created during
enrollment. After enrollment has been completed and the switch is set to verification, the LCD displays a
message asking for a finger to be placed on the sensor. If no finger is placed, a timeout occurs and the LCD
displays the same request. If a finger is placed on the sensor, the fingerprint will be captured and compared
to the template.
If the fingerprint matches the template, then the following message will be displayed:
Congratulations!
Your fingerprint has
been verified.
If the fingerprint does not match the template, the following message will be displayed:
Sorry,
Your fingerprint has
failed verification.
The demonstration remains in verification mode until the switch is moved back to enrollment. When
enrollment is selected, the previous template is erased and a new one is created by the next successful
enrollment.
4
Additional Information
To demonstrate the versatility of the fingerprint algorithm during verification, the correct finger can be
placed on the sensor in different orientations, or it can be moved around with a fixed orientation. Also, a
comparison can be made between dry and wet fingers, resulting in different enroll scores. Experiments like
these highlight how the correct fingerprint can be verified in a variety of conditions.
Another feature of the fingerprint algorithm can be used to alert the user to the verification of latent
fingerprint images (residual fingerprints left on the surface of the sensor). Since these images can be used
to fool the system if the sensor takes an image when no finger is present, the algorithm detects, based on
adjustable rotational and translation thresholds, images that are too close or identical to the last matched
fingerprint. If the captured fingerprint image is detected as identical to the previous matched image, the
LCD will display a message that indicates this condition. The algorithm’s ability to detect latent fingerprint
images can be demonstrated during verification by leaving the finger on the sensor.
There is also a web server running on the MCF5249 as part of the application that displays the images taken
from the sensor. There is one page that shows the seven images taken as part of the enrollment mode, and
another page that shows the last image taken by the sensor.
To demonstrate the web server, connect a crossed Ethernet cable directly to the PC, and switch the proxy
server off in Internet Explorer (Tools/Internet Options/Connections/LAN settings) before opening the
webpage http://10.0.0.10 via the address bar.
To return to booting with dBUG after using the Flash version, switch jumper 12 back to pins 1–2.
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc.
..
