The present disclosure relates to an image processing apparatus. The image processing apparatus according to an embodiment of the present disclosure includes a display having a plurality of pixels, and a controller, wherein the controller: calculates an average luminance value of a first frame of an image based on RGB data corresponding to the image; sets a criterion for determining an output level of the plurality of pixels according to the average luminance value of the first frame; controls the display to output a first frame group, including the first frame, according to the set criterion; calculates an average luminance value of a second frame of the image according to a predetermined cycle; resets a criterion for determining the output level of the plurality of pixels according to the average luminance value of the second frame; and controls the display to output a second frame group, including the second frame, according to the reset criterion. Accordingly, by dynamically changing the criteria for determining the output level of the plurality of pixels included in the display based on the luminance value of each frame of the image, the image may be displayed more clearly. Various other embodiments are possible.