| 摘要 |
PURPOSE: A solid-state image pick-up device and a fingerprint collating apparatus using the same are provided to improve image pick-up ability by using an average computing unit and a conversion unit for converting the result of the average computing unit into a gain control signal and to precisely perform a gain adjustment. CONSTITUTION: A sensor array(1) is composed of photoelectric conversion cells arranged in the form of a matrix. An X scanner(2) and a Y scanner(3) scan the respective photoelectric conversion cells. A VGA(Variable Gain Amplifier)(5) amplifies output voltages of the respective photoelectric conversion cells, and an ADC(Analog to Digital Converter)(6) converts an output voltage of the VGA into digital data. An average computing unit(11) computes the average value of output voltages of the respective photoelectric conversion cells in a predetermined area of the sensor array on the basis of the output of the ADC. A divider divides a reference value by the average value and outputs the result of division to a multiplier. The multiplier multiplies together the output of a register having a gain control signal for the previous frame stored in it and the output of the divider, and outputs the result of multiplication to the VGA as a gain control signal. Since the device controls the gain of the VGA on the basis of the average value of outputs of photoelectric conversion cells in the specific area, precise performance of a gain adjustment is possible.
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