Noise reduction apparatus and method

Noise reduction processing in accordance with frequency band is executed. To accomplish this, a image data dividing circuit divides image data into image data having frequencies in a low-frequency region, image data having frequencies in a low- to intermediate frequency region and image data having frequencies in a low- to high-frequency region. These items of image data thus divided on a frequency-band basis are input to respective ones of noise reduction circuits that have been set to respective ones of parameters suited to noise reduction of image data having frequencies in the low-, low- to intermediate and low- to high-frequency regions, respectively. The items of image data that have thus undergone noise reduction processing conforming to frequency band are input to an image data combining circuit. The latter combines the image data so as to obtain image data representing one frame of an image.