Patent ID: 8558942

Claim:
A focusing measurement device, comprising: an image input section obtaining a captured image; a first filter section generating a first blurred image by using a first blur filter for the captured image and generating a second blurred image by using a second blur filter for the captured image, the second blur filter having different frequency characteristics from the first blur filter; a second filter section generating a third blurred image by using a third blur filter for the captured image, the third blur filter having the frequency characteristics being a low frequency side relative to the frequency characteristics of the first blur filter, and generating a fourth blurred image by using a fourth blur filter for the captured image, the fourth blur filter having frequency characteristics being a low frequency side relative to the frequency characteristics of the first blur filter and having different frequency characteristics from the third blur filter; a first focusing calculating section calculating a first focusing amount indicating a degree of in-focus by using first amounts of displacement between a first difference and a second difference along with obtaining the first difference between the first blurred image and the captured image, and obtaining the second difference between the second blurred image and the captured image; a second focusing calculating section calculating a second focusing amount indicating a degree of in-focus being a low frequency side relative to the first amounts of displacement by using second amounts of displacement between a third difference and a fourth difference along with obtaining the third difference between the third blurred image and the captured image, and obtaining the fourth difference between the fourth blurred image and the captured image; and a measurement section measuring a focusing level of the captured image by using a difference between the first focusing amount and the second focusing amount.