Patent ID: 8717454

Claim:
An image pickup apparatus comprising: an image pickup unit that acquires a first image without a flash by a down-sampling process and acquires a second image with the flash, wherein the second image has a larger number of pixels than the first image; a down-sampling unit that acquires a third image by performing a down-sampling process on the second image in such a way that a size of the second image is the same as a size of the first image; a subject brightness calculator that calculates a first subject brightness for all pixels of the first image and calculates a second subject brightness for all pixels of the third image; a subject brightness difference calculator that calculates a subject brightness difference, wherein the subject brightness difference corresponds to a difference between the first subject brightness for all the pixels of the first image and the second subject brightness for all the pixels of the third image; a flash reflection intensity calculator that calculates a first flash reflection intensity in a unit of a pixel from the subject brightness difference; a first flash reflection intensity interpolator that calculates a second flash reflection intensity through interpolation to reduce an influence of a position mismatch between the first image and the third image for the first flash reflection intensity in a unit of a pixel by using pixel-based brightness values of the third image; a second flash reflection intensity interpolator that calculates a third flash reflection intensity through interpolation to magnify a size of the data corresponding to the second flash reflection intensity to correspond to the size of the second image wherein the interpolation is performed using pixel-based brightness values of the second image; and a white balance gain calculator that calculates a white balance gain in a unit of a pixel from the third flash reflection intensity.