A method of improving an image quality of a video signal, which is supplied on a frame-by-frame basis, includes extracting low frequency components from a video signal of an n-th frame, where n is a natural number excluding zero, subtracting the extracted low frequency components from a video signal of an (n+m)th frame to produce high frequency components, where no is a natural number excluding zero, and adding the produced high frequency components to the video signal of the (n+m)th frame. The extracted low frequency components include a horizontal component and a vertical component.