Patent ID: 9479690
Filing Date: 2016-10-25
CPC Classification: G02B,G03B,G06K,H04N

Claim Text:
1. A photographing apparatus comprising: a focus lens; a lens drive unit which moves the focus lens in an optical axis direction; an imaging unit which images an object at an interval of a predetermined time through the focus lens moving in the optical axis direction, and generates a plurality of pieces of image data; a frequency component extraction unit which extracts a spatial frequency component from each piece of image data using a first filter and a second filter as high pass filters, a cutoff frequency of the first filter being higher than a cutoff frequency of the second filter; an AF evaluation value acquisition unit which integrates the spatial frequency component extracted by the first filter to acquire a first AF evaluation value, and integrates the spatial frequency component extracted by the second filter to acquire a second AF evaluation value; an arithmetic unit which subtracts a value obtained by multiplying or adding a predetermined constant to the first AF evaluation value from the second AF evaluation value to calculate an arithmetic value, the arithmetic value being calculated as E a variation calculation unit which calculates a variation of the arithmetic value at an interval of the predetermined time; a moving speed control unit which controls a moving speed of the focus lens by the lens drive unit based on the variation; and a focal position detection unit which detects a focal position of the focus lens based on at least one of the first AF evaluation value and the second AF evaluation value.