OPTICAL FINGER PRINT INPUT APPARATUS AND METHOD FOR DETERMINING REMAINING IMAGE ON THE SAME

摘要

An optical fingerprint input device and a remaining image determining method thereof are provided to remove a remaining image by extracting an optimal element performing a complementary role from each image obtained in a power-on/off state of an internal light source. A prism(100) includes a fingerprint input window, and changes an optical path by reflecting or refracting light. A lighting system(110) includes the internal light source and makes the internal light source emit the light to the fingerprint input window to make a fingerprint image. An image sensor(130) detects the image of a fingerprint put on the fingerprint input window and outputs the detected image as an electric image signal. An image processor(140) recognizes a fingerprint pattern by formatting the image signal output from the image sensor into a digital signal and processing the digital signal, and discriminates whether the obtained image is the remaining image or not by using the first and second element respectively extracted from the image when the internal light source is turned on and off.