1. An apparatus for processing an image, comprising: a subject information acquiring unit for extracting subject information contained in an input image from the input image; a display information acquiring unit for acquiring display information representative of a performance of a display for displaying the input image; an enhancement parameter determining unit for determining an enhancing degree as a parameter for enhancing a sharpness of the input image by using at least one of the subject information and the display information; and an enhancing processing unit for carrying out a sharpness enhancing process on the input image by using the enhancing degree.