AUTOMATIC FOCUS DETECTION DEVICE AND FOCUS DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide an automatic focus detection device and a focus detection method that enable focus detection accuracy to be maintained even with respect to a subject on which an interpolation synthesis of an image signal adversely affects without performing a wasteful determination process.SOLUTION: An automatic focus detection device has: zigzag alignment first and second line sensors onto which a pair of pupil-division subject ray fluxes is projected; and amount-of-image deviation detection means for detecting the amount of image deviation from image signal strings output from criterion sensor areas of the first and second line sensors and reference sensor areas thereof. When contrasts of the image signal strings of the first and second line sensors are a prescribed value or more, the amount-of-image deviation means calculates the amount of image deviation between the sensors in the criterion sensor area of the first and second line sensors and the amount of image deviation between the sensors in the reference areas thereof, and, when a difference in the amount of image deviation between the sensors is a first prescribed value or less and a magnitude of the amount of image deviation between each of sensors is a second prescribed value or less, the amount-of-image deviation detection means takes out image signals of the first and second line sensors to implement an interpolation synthesis to the image signals, and calculates the amount of image deviation between the criterion sensor area and the reference area on the basis of the signal subjected to the interpolation synthesis.