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