A method, medium and system processing an image signal. The system includes an edge detection module to detect a pixel belonging to an edge in an input image, a period determination module to determine a period of change in pixel values based on a first value of the pixel belonging to the edge and a second value of a pixel that is adjacent to the pixel belonging to the edge, and a signal correction module to correct one or more sub-pixels of the pixel belonging to the edge using a weight allocated according to a result of the determination performed by the period determination module.