An image processing method includes the following steps. First, noise of a first image is filtered, and the first image is converted to obtain a first luminance signal. Second, a color space converting process is performed upon the first image to obtain a second image. Third, the second image is stored and outputted. Fourth, noise of the second image is filtered, and the second image is converted to obtain a second luminance signal. Fifth, a linear computing is performed to obtain a third image. Sixth, an error compensation is performed upon the third image and the second image, and the third image is outputted. Seventh, the color space converting process is performed to obtain and output a fourth image. The linear computing and the error compensation are performed upon a single image to filter the noise of the images, and thus a load of a system may be decreased.