An image processor of a display device includes: an image sticking object detector which classifies a class of an input image data and outputs inference data including image sticking object information based on the classified class; a memory which stores previous inference data; a post-processor which calculates accumulative inference data, based on the inference data and the previous inference data received from the memory and generates corrected inference data, based on the accumulative inference data; and an image sticking prevention part which outputs an image data subjected to an image sticking prevention process, based on the corrected inference data.