| 摘要 |
PURPOSE:To prohibit input of a false fingerprint pattern by judging whether the light incident to a detecting means based on a detected density passes through one or both of the first and the second zone passing means. CONSTITUTION:In case of attempting to input a false fingerprint by using an external light beam for a false input, a density value of a background section of a fingerprint image detected by a detector 6 is the irradiating light from the external light beam and determined by the light passing only through a zone passing filter 16. Accordingly, if the passing zone of a zone passing filter is set so as to produce slippage between the passing zone passing filter 15 and the passing zone of the zone passing filter 16, the density value of the background section of the fingerprint image obtained by a detector 6 by the light from an internal light source 2 is different from the density vlaue of the finger print image obtained by the detector 6 by the light from the external light beam, and a judgement whether the false fingerprint is input or not is made possible.
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