| 摘要 |
PURPOSE:To suppress a decrease in contrast or an SN ratio due to residual oils and fats by forming a surface which scatters light as at least a surface which is pressed with a finger on the surface of a transparent body. CONSTITUTION:While the finger 12 is pressed against the surface of the transparent body 11 which operates as a scattering surface by uneven machining, the top surface side of the transparent body 11 is lighted from its reverse surface side and scattered light from the top surface of the transparent body 11 is detected to obtain an image wherein a fingerprint image is embossed in the scattered light, i.e. a fingerprint image. In this case, neither a laser nor an expensive lens, etc., is required and the structure may be simple. Consequently, the influence of reasidual oils and fats sticking once on the surface of the transparent body is reducible and the decrease in the contrast or the SN ratio can be suppressed. |
