| 摘要 |
The method detects, by means of a sensor (1), the image of a fingerprint (3) and uses a coder (10) connected to the sensor, to extract from the image characteristics representing the fingerprint. In the dialogue between coder and sensor a randomly selected extraction parameter is randomly modified for each part of the fingerprint detection operation so as to make the dialogue unreadable when observed from outside the coder. The randomly changed extraction parameter is the sequence and/or the cut (dimension) of the sub-image defined in the detected image. The randomly changed extraction parameter comprises, in the request for sub images, of cuts from the detected image non useful for the extraction of characteristics. The randomly exchanged extraction parameter is an image quality parameter. The coder verifies that the sensor has effectively executed a coder controlled instruction. An Independent Claim is included for a fingerprint detector with image sensor, coder with sensor drive (6) and connections (4). The coder has a circuit designed to randomly modify at least a parameter of an instruction generated by the coder for sending to the detector for extracting characteristics of the fingerprint.
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