1. An image processing device for obtaining a depth information image representing a distribution of depth information about an object on the basis of a raw first image and a raw second image that have different degrees of blurring, the first and second images being captured by an image sensor having a plurality of groups of pixels each group including a red pixel that obtains red information, a green pixel that obtains green information, and a blue pixel that obtains blue information, the image processing device comprising: a mixing unit configured to mix signals of the red pixel, the green pixel, and the blue pixel and generate a first mixed image and a second mixed image respectively corresponding to the first raw image and the second raw image; an extracting unit configured to extract signals, each corresponding to one of the red pixel, the green pixel and the blue pixel of each group, from each of the first mixed image and the second mixed image and generate a first extracted image and a second extracted image respectively corresponding to the first mixed image and the second mixed image; and a calculating unit configured to calculate the depth information image from a difference in degree of blurring between the first extracted image and the second extracted image.