Patent ID: 7990431

Claim:
A calculation method for calculating a white balance correction value for use in an image capture device that stores a color temperature of a default auxiliary light CT 2 and a relationship table of a pulse width P and a default brightness R, comprising: (A) under the same scene, capturing a first image and a second image having an auxiliary light, wherein a brightness of the auxiliary light is supplied with a first pulse width; (B) obtaining an environment color temperature CT 1 and a first environment brightness Y 1 from the first image; (C) obtaining a second environment brightness Y 2 from the second image; (D) subtracting the first environment brightness Y 1 from the second environment brightness Y 2 to obtain a first flash brightness F 1 ; (E) supplying the brightness of the auxiliary light with a second pulse width P 2 to obtain a third image; (F) obtaining a first default flash brightness R 1 and a second default flash brightness R 2 by looking up the relationship table of the pulse width P and the default brightness R and calculating the second flash brightness F 2 by a second flash brightness formula, wherein F ⁢ ⁢ 2 = R ⁢ ⁢ 2 R ⁢ ⁢ 1 × F ⁢ ⁢ 1 ; and (G) calculating a white balance correction value WB by a white balance correction value formula, wherein WB = CT ⁢ ⁢ 1 × Y ⁢ ⁢ 1 + CT ⁢ ⁢ 2 × F ⁢ ⁢ 2 Y ⁢ ⁢ 1 + F ⁢ ⁢ 2 .