An image processing unit has an image acquisition part, a correlation determination part, a reference image generation part, and an interpolation image generation part. The image acquisition part acquires an original image. The correlation determination unit determines whether the correlation of an image component of a primary reference band with image components of respective bands other than the primary reference band is either high correlation or low correlation. The reference image generation part interpolates missing pixels in the image component of the primary reference band by switching the interpolation method based on the correlation determination result obtained by the correlation determination part. The interpolation image generation part interpolates, using the correlation determination result and the primary reference image, missing pixels in at least some of the image component of the primary reference band.