1. An image processing apparatus, comprising: a reduced image generation section generating a first reduced image obtained by reducing at least a target image being a noise reduction target, out of the target image and a reference image to be a reference of a noise reduction processing; a noise extraction section extracting a noise component in a frequency band corresponding to a reduction ratio of the first reduced image by using at least the first reduced image; and a noise reduction section reducing the noise component in the frequency band from a pixel value of each pixel of the target image based on the noise component in the frequency band being extracted.