Patent ID: 8860863

Claim:
An image pickup method using an image pickup apparatus including a charge coupled device (CCD) image pickup device, a first acquisition unit for acquiring an image signal outputted from effective pixels of a light-receiving face of the CCD image pickup device, a second acquisition unit for acquiring a signal outputted from shaded pixels of at least one of upper, lower, left, and right portions of the light-receiving face of the CCD image pickup device, an automatic gain control unit, a calculation unit for calculating a representative value of the signal outputted from the shaded pixels acquired by the second acquisition unit, a screen memory for storing a dark current component outputted from the effective pixels acquired by the first acquisition unit, a line memory for storing an effective pixel signal outputted from the effective pixels acquired by the first acquisition unit, and a subtraction unit for performing a variable gain amplification of the stored dark current component outputted from the effective pixels and subtracting it from the effective pixel signal, the method comprising: controlling a variable gain amplification above a vertical period of the effective pixel signal in plus correlation with an average above the vertical period of the representative value of the signal outputted from the shaded pixels; and controlling a variable gain amplification of a horizontal period of the effective pixel signal in minus correlation with a ratio between a value of the horizontal period of the representative value and the average above the vertical period of the representative value or a ratio between a recursive average in screens of the representative value and the average above the vertical period of the representative value.