FOCUS DETECTION DEVICE AND AMOUNT OF IMAGE DEVIATION DETECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a highly accurate focus detection device.SOLUTION: The focus detection device comprises: an image sensor; image synthesizing means for generating a synthesized image signal string by mutually adding and synthesizing a pair of relatively shifted image signal strings; contrast extraction means for generating a contrast signal string by extracting a plurality of contrast components from the synthesized image signal string; contrast evaluation means for calculating a contrast evaluation value of the synthesized image signal string on the basis of a non-linear contrast signal string having the contrast signal string converted; image deviation amount detection means for detecting the amount of a shift corresponding to an extremal value in a plurality of contrast evaluation values as the amount of an image deviation; and defocus amount calculation means for calculating the amount of a defocus of an optical system.