Patent ID: 9584717
Date: 2017-02-28
CPC Classifications: H04N

Claim:
1. A focusing method to be implemented by an image capturing device, the image capturing device including an image sensor, a lens module that is movable relative to the image sensor, a focus driver that is for driving movement of the lens module, and a processor module that is connected electrically to the image sensor and the focus driver, the lens module including a first diaphragm and a second diaphragm different from the first diaphragm, the focusing method comprising the steps of: detecting simultaneously, by the image sensor, light energy of a first spectrum and light energy of a second spectrum which are associated with an image containing an object when the lens module is located at an initial position, for respective generation of a first image data corresponding to the light energy of the first spectrum and a second image data corresponding to the light energy of the second spectrum, each of the first image data and the second image data being associated with a respective one of the first diaphragm and the second diaphragm, a distance between the lens module which is located at the initial position and the image sensor being defined as an initial image distance; obtaining, by the processor module according to the first image data and the second image data, a first circle of confusion diameter and a second circle of confusion diameter which are associated with the object and which correspond respectively to the first image data and the second image data; calculating, by the processor module, a diameter difference between the first circle of confusion diameter and the second circle of confusion diameter; generating, by the processor module, a control signal associated with a target image distance at least according to the initial image distance, the diameter difference, and a lookup table which contains information of at least one image distance and at least one corresponding difference between circle of confusion diameters; and driving, by the focus driver according to the control signal, movement of the lens module so as to change the distance between the lens module and the image sensor from the initial image distance into the target image distance.