CM security FPC1381, Руководство пользователя

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FingerPrintScan System FPC 1381
– Technical Handbook
Version 2.00 page 7
9. The Function of the Thermal Line Sensor
Layout: The thermal sensors are located in a narrow, elongated block.
Function: If a finger is placed over the block, the thermal sensors register temporal
temperature changes.
The temperature differences between the lines and grooves of a fingerprint are so
large that they can be recognised by the line sensor. The temperature differences are
digitally processed by a micro controller and a greyscale image is calculated. The
accuracy of the line sensor is such that a picture with a resolution of approx. 500dpi
can be generated. From this picture the lines of the finger are digitally measured. The
angle and position of distinct points (minutiae) are determined. Finally, these
minutiae are either compared with information in the database or stored.