1. An image processing apparatus, comprising: a first image generating unit configured to divide an input image into bands to generate an image that includes a direct current component and at least one image that does not include the direct current component; a second image generating unit configured to generate a plurality of images from the image that has been generated by the first image generating unit and includes the direct current component, the images each including the direct current component and having a different resolution; a noise suppressing unit configured to perform noise suppression processing on the images generated by the first image generating unit and on the images generated by the second image generating unit; a first combining unit configured to combine the plurality of images generated by the second image generating unit and subjected to the noise suppression processing; and a second combining unit configured to combine a composite image from the first combining unit and the at least one image that does not include the direct current component and has been subjected to the noise suppression processing.