Patent ID: 9749563
Date: 2017-08-29
CPC Classifications: G02B,G03B,H04N

Claim:
1. A focal point detection device, comprising: an image sensor having a focal point detection pixel where an incident direction of an incident light flux is restricted and an imaging pixel where the incident direction of the incident light flux is not restricted; a pixel data generation section to generate focal point detection pixel data of a basis part and a reference part corresponding to a predetermined AF area using an output of the focal point detection pixel; a plurality of filter sections having different frequency characteristics to perform filter processing on the pixel data; a detection section to detect contrast of subject image data configured with a plurality of pieces of pixel data of the basis part and the reference part; a calculation section to select a filter section from among the plurality of filter sections depending on the contrast output by the detection section, to perform correlation calculation using pixel data obtained by performing filter processing on the pixel data of the basis part and the reference part with the selected filter section, and to calculate a defocus amount; a moving object discrimination section to discriminate whether a subject is a moving object or not, using imaging data output from the imaging pixel; and a reliability determination section to determine reliability of an output from the calculation section, wherein the plurality of filter sections includes a first filter processing section having a predetermined frequency characteristic and a second filter processing section having a frequency characteristic which exhibits a larger gain for a low frequency component than the frequency characteristic of the first filter processing section, the calculation section selects the second filter processing section to perform calculation when the contrast output by the detection section is lower than a predetermined value, and the calculation section selects the second filter processing section to perform calculation when the moving object determination section determines that the subject is a moving object while the correlation calculation by the calculation section and the reliability determination by the reliability determination section are carried out repeatedly on the basis of pixel data obtained by repeatedly performing imaging operation by the image sensor, and also when the reliability determination section continues to determine that reliability is low for a predetermined time or longer while the calculation section selects the first filter processing section to perform calculation, wherein the detection section detects an addition value of a difference between a maximum value and a minimum value out of a plurality of pieces of pixel data of the basis part and a difference between a maximum value and a minimum value out of a plurality of pieces of pixel data of the reference part.