IN-FOCUS POSITION DETECTION DEVICE, IN-FOCUS POSITION DETECTION METHOD, AND IN-FOCUS POSITION DETECTION COMPUTER PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an in-focus position detection device that can improve detection accuracy upon detecting an in-focus position using a phase difference detection method.SOLUTION: An in-focus position detection device includes: a characteristic-amount calculation unit 12 that, as to each shift-amount calculation area within a measurement area to be set on an image sensor 21 of an imaging unit 2, calculates a local amount of shift of a second sub-image with respect to a first sub-image and an amount of characteristic of a probability distribution showing probability of the local amount of shift when a subject on the first sub-image and a subject on the second sub-image best match; a probability distribution estimation unit 13 that estimates a probability distribution of the local amount of shift on the basis of the local amount of shift and the amount of characteristic as to each calculation area of the amount of shift; a synthesis unit 14 that synthesizes the probability distribution of the local amount of shift of each shift-amount calculation area to obtain a distribution of the probability of the local amount of shift as to the measurement area; and a representative value calculation unit 15 that calculates a representative value showing a distance between an in-focus position by an optical system 22 of the imaging unit 2 and the image sensor 21 on the basis of the distribution.SELECTED DRAWING: Figure 4