Patent ID: 9703070
Date: 2017-07-11
CPC Classifications: G02B,G03B,H04N

Claim:
1. An imaging apparatus comprising: a focus lens configured to be movable in an optical axis direction; an imaging element configured to image an object via the focus lens; an evaluated value calculation unit configured to calculate an evaluated value for focusing using a picked-up image signal obtained through imaging by the imaging element at every position of the focus lens while moving the focus lens; a sharpness calculation unit configured to calculate a sharpness in a vicinity of a maximal point of an evaluated value curve, which represents relationship between a position of the focus lens and the evaluated value, using at least three evaluated values calculated by the evaluated value calculation unit and position information of the focus lens corresponding to each of the at least three evaluated values; a focusing position calculation unit configured to select, according to at least the sharpness calculated by the sharpness calculation unit, one of plural kinds of calculation methods using the at least three evaluated values and the position information of the focus lens corresponding to each of the at least three evaluated values, and to calculate the position of the focus lens corresponding to the maximal point of the evaluated value curve as a focusing position using the selected calculation method; a focusing control unit configured to perform a focusing control to move the focus lens to the focusing position; and at least one processor configured to function as the evaluated value calculation unit, the sharpness calculation unit, the focusing position calculation unit, and the focusing control unit, wherein the plural kind of calculation methods include: a first calculation method for calculating a second or higher degree function representing the evaluated value curve using the at least three evaluated values and the position information of the focus lens corresponding to each of the at least three evaluated values, and calculating the focusing position using the second or higher degree function; and a second calculation method for calculating a first degree function using the at least three evaluated values and the position information of the focus lens corresponding to each of the at least three evaluated values and calculating the focusing position using the first degree function, and wherein the at least three evaluated values include a maximum value among the evaluated values calculated by the evaluated value calculation unit and evaluated values calculated in relation with positions in front and rear of the position of the focus lens corresponding to the maximum value.