Highlights from the "Madrid Report"
About the study:
Under the management of professor Raul Sanchez-Reillo at University Carlos III of Madrid, a highly respected biometric industry resource, extensive comparative tests involving 3 market leading sensors have been executed. The study involved collection of more than 180.000 fingerprints from 600 people over a period of 4 months and more than 300 million comparisons using world-class leading algorithms.
The Madrid study has been performed independently of NEXT and the suppliers of the 2 market leading capacitive sensors used. ISO-standard best practices methodology has been applied. Sequence of sensors for print collection has been randomized for every test subject, the population used has been representative in a mass market context, the origin of the sensors used has been kept confidential to the operators and subjects involved in the test. All test subjects have been requested to do the acquisition in 2 sessions, with minimum 2 weeks break between each test.
Why this study ?
We wanted to have an independent 3rd party high volume, mass market realistic study performed to prove beyond all reasonable doubt what any experienced biometric industry expert will confirm: a reliable fingerprint system cannot compromise on sensor area.
The studies document dramatic size related system performance variations. Sensor size is proven as the key factor determining the overall performance of a sensor system. Other variables like sensing principleand sensor resolution play a far less significant role.
When the active area of a fingerprint sensor is halved from 200 to 100 mm2, the false rejection rates grow dramatically as the study shows. A typical system configured to 1 in 10,000 false acceptance rate (FAR) will achieve less than 1% false reject rate (FRR) for a full-sized area sensor (>200mm2), while the average FRR increases dramatically to more than 5% for a 100mm2 sensor. This proves that the NEXT quality area sensor is far superior to any commercial touch sensor implementing only 10x10 or even 8x8 mm active area.
For small sensors, some improvement can be realized by «stitching» during initial finger enrollment. Here multiple finger placements are required to reconstruct a complete fingerprint from smaller fragments. While this method is subject to several international patents, it can only partially compensate the lack of area.
The end result of such high false rejections with small sensors is that a significant %-age of any given population will simply not be able or interested in using the system.
Implications for NEXT
NEXT sensor performance is far superior to competing mass market priced sensors. The Madrid study document that the NEXT sensor performs similar to similar sized, expensive and government approved fingerprint readers
The study also document that the ability to acquire and the capture time using the NEXT Active Thermal™ sensors is in line with the results of the 2 competing capacitive sensors. The NEXT sensor was even superior to others by NIST NFIQ assessment of image quality.
Also bear in mind
The Madrid study has been performed in an operator-guided, in-door environment. In real life applications variables related to user behavior and environment add further complexity. In a out-door use case with impatient or careless users, the frequency of wet fingers, dirty fingers and skewed placements will increase. In such use cases the dependency of sensor size is even more critical – the false rejections rates of small sized sensors deteriorates to levels found unacceptable by most users.
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