4Flats Fingerprint Device Design And Realization

With the development in high-tech and net-work, people pay more attention to personal ID authentication and information security. Especially since "9.11" accident took place, more and more countries attach high importance to security and increase the anti-terrorism budget year after year, such as voice、palm、iris、retina、face、 fingerprint, various bio-metric recognition systems are widely used by governments, police station, commerce organizations. Because of feature extracting convenience, maturate arithmetic, precise data match rate, fingerprint identification technology is well recognized and common used by individuals and organizations. There are three modes for fingerprint to collect information:traditional ink printing, criminal spot fingerprint collection, living creature scan.The article is subject to four-flats living fingerprint capture device. On the top of operating principle、technique criterion、system composition, the schematic diagram and hardware solution are supplied. In this article the key components control method is dissertated including CCD register control、CCD time sequence control、CCD noise variety、CCD noise restraining、CCD image preprocessing analysis and so on.FBI fingerprint image quality criterion is dissertated in the article detailedly, a lot of relevant arithmetic is discussed including image rotation、image mirror、experienced threshold fingerprint detection、CCD Odd/Even frame image merging、RGB channel white balance、device calibration、automatically adapt to the fixed and changing step detection. There are two innovation in the article:Firstly by initialization calibration algorithm, the diversity in hardware is diminished and the impact by image background is reduced; Secondly by automatic adaptive detection arithmetic, discrepancy of different fingers is decrease, then according to the feedback, it adjusts lighting source luminance, CCD sensor gain amplifier and exposure parameter, result in the final picture is perfect as has proper image brightness, consistency grayscale, wide-dynamic range, excellent uniformity.To test4flats fingerprint device to show:compared with the single fingerprint recognition device, the four-flats fingerprint device has more advantages.4flats fingerprint device can decrease operation errors, improve the recognition accuracy greatly because of4fingerprint device in image’s better quality and uniformity, to be compatible with the all countries and regionsstandards, can realize series fingerprint collection mode, such as:10single flat fingers capturing,10single fingers rolling capturing, double forefingers flat capturing; double forefingers rolling capturing, double flat thumbs capturing, double thumbs rolling capturing,2-2flats mode (left forefinger&midfinger+right forefinger&midfinger),4-4-2flats mode (left four fingers+right four fingers+double thumbs).The device is passed by FCC/CE、FBI image quality、IP54dustproof and waterproof attestation and shockproof test. The test result show that the device is reliable, all prospective design requirement is achieved. For next general half palm and full palm product, will think of high capacity buffer、high speed transmission rate、 living life detection and so on.