DARK CURRENT CORRECTION DEVICE FOR PHOTOELECTRIC CONVERTER

摘要

PROBLEM TO BE SOLVED: To correct dark current accurately in a short time without the need for a memory with a large capacity. SOLUTION: A difference between a dark current of a specific picture element of a photoelectric converter consisting of a plurality of picture elements and a mean dark current of picture elements other than a specific picture element is stored and the difference is subtracted from the output current of the specific picture element of the photoelectric converter to correct the dark current. Thus, the storage capacity of a memory to store dark current correction data is reduced and the correction processing time is reduced. Since the large dark current of the specific picture element is reduced up to a mean dark current level of the peripheral picture element, the dark current level of all the picture elements after correction of the dark current is averaged and the dark current correction device is used for the photoelectric converter for a focus detector to improve the accuracy and reliability for focus detection.