Patent ID: 8131027

Claim:
A finger contact detecting apparatus which detects a finger being swept on a fingerprint sensor, the finger contact detecting apparatus comprising: a pixel data averaging unit configured to calculate an average value of pixel data collected by the fingerprint sensor; a deviation adding unit configured to calculate, based on the average value and respective pixel data of predetermined pixels obtained by the fingerprint sensor, a summation of deviations of the respective pixel data of the predetermined pixels; and a finger contact detecting unit configured to determine whether the finger is separated from the fingerprint sensor based on the summation of deviations and a predetermined threshold value, wherein the fingerprint sensor includes a line sensor provided with plural pixels arranged in a line shape, the finger contact detecting unit is configured to compare the summation of deviations and the predetermined threshold value, and when a state where the summation of deviations is less than the predetermined threshold value continues for more than a predetermined number of lines, the finger contact detecting unit is configured to determine that the finger is separated from the line sensor.