Patent ID: 7825960

Claim:
An electron multiplication gain calibration mechanism for calibrating an electron multiplication gain of an electron multiplying CCD image pickup device capable of obtaining a desired electron multiplication gain by selecting an electron multiplication gate voltage, comprising: a gain adjusting section which is provided independently of gain adjustment by electron multiplication of the electron multiplying CCD image pickup device, and sets a predetermined reference gain for a video level of an electric signal having passed through the electron multiplying CCD image pickup device; and a control section which calibrates the electron multiplication gate voltage for obtaining a desired electron multiplication gain of the electron multiplying CCD image pickup device by comparing a video level amplified by the electron multiplication gain corresponding to the electron multiplication gate voltage having set to the electron multiplying CCD image pickup device to a video level amplified by the predetermined reference gain having set to the gain adjusting section and, wherein, the video level amplified by the predetermined reference gain is obtained without applying the electron multiplication gain, and the control section sets an initial value of the electron multiplication gate voltage, which is supposed to provide the electron multiplication gain equal to the reference gain, and controls, without applying the predetermined reference gain, the electron multiplication gate voltage so that the video level amplified by the electron multiplication gain becomes equal to the video level amplified by reference gain.