1. An image processing apparatus comprising: an input unit configured to input image data including m frame images per unit time; a filtering unit configured to generate a high-frequency component emphasized frame image and a low-frequency component frame image from each frame image included in the input image data; a correction unit configured to correct a luminance of the low-frequency component frame image corresponding to each frame image at a predetermined ratio so as to make the image data perceptible in the same brightness as that of each of the frame images output as the m frames per unit time; and an output unit configured to alternately output the high-frequency component emphasized frame image generated by said filtering unit and the low-frequency component frame image whose luminance has been corrected by said correction unit as image data including 2 m frame images per unit time.