Patent ID: 7224397
Filing Date: 2007-05-29
Classification: H04N

Abstract:
1. An AF control apparatus for executing AF (automatic focusing) control of an optical system mounted in a camera, comprising: an image pickup sensor for detecting an incident light from a subject; a light source for emitting an auxiliary light to said subject; a differential signal calculating section for outputting a differential signal between a first image signal which is obtained by image pickup by said image pickup sensor when said light source does not emit said auxiliary light, and a second image signal which is obtained by image pickup by said image pickup sensor when said light source emits said auxiliary light; a distance measuring section for calculating distance information to said subject based on said differential signal; an AF control section for controlling an AF operation of said optical system based on said distance information; and a reflectance calculating section for calculating a reflectance of said subject based on said first image signal, wherein said distance measuring section calculates said distance information using said reflectance calculated at said reflectance calculating section under the condition that intensity of said auxiliary light attenuates in accordance with the inverse-square law.