DARK CURRENT CORRECTING METHOD FOR CCD SENSOR

摘要

PURPOSE:To correct the dark current of a CCD sensor, by taking difference between the dark current stored at the 1st period and a signal obtained throgh the readout and scanning at the 2nd period. CONSTITUTION:The output of a CCD sensor is read out at the 1st part period of A, while a shutter 3 is closed, and it is digitized at an A/D converter 5 and stored in a memory circuit 6. At the 2nd part B, the shutter 3 is opened and an objective 4 is scanned and the signal from the CCD sensor 1 is read out. The signal in this case is a video signal of the objective 4 superimposed on the dark current. The signal read out at the period B is digitized at the circuit 5 and given to a differential circuit 7. A signal read out at the period A stored from the circuit 6 is given to the circuit 7, and the difference between them is taken to obtain the video signal for one scanning period's share with the corrected dark current.