| 摘要 |
PROBLEM TO BE SOLVED: To obtain a fingerprint image input device which can surely perform living body identification in spite of no change in color information of the fingerprint image. SOLUTION: A finger F, which comes in contact with an inspection surface 12a of a transparent body 12, is irradiated with a probe light L1 having a wavelength of an area in which an absorption coefficient of oxidized hemoglobin is smaller than that of reduced hemoglobin, and a reference light L2 having a wavelength of an area in which the absorption coefficient of the oxidized hemoglobin and that of the reduced hemoglobin are almost identical from a living body identification light source 11. A transmitting light detection means 13 receives a transmission probe light L11 of the probe light L1 which transmits through inside the finger F and outputs an electric signal S2 in accordance with a light intensity of the light L11, and receives transmission reference light L12 transmitting the inside of the finger F and outputs an electrical signal, in accordance with the intensity of the light L12. Through both of the electrical signals S1 and S2 outputted from the transmission light detection means 13, a transmission light intensity ratio of the light intensity of the transmission probe light L11 and the light intensity of the transmission reference light L12 are obtained, and a living body identification means 15 identifies from this transmission light intensity ratio whether or not the finger F touching the inspection surface 12a is a living body.
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