An image processing apparatus includes a display configured to display a medical image； an input unit configured to receive n (n being an integer equal to or greater than three) number of input points with respect to the displayed medical image； and a controller configured to set a window in the medical image based on an area in a shape of a polygon, the area being defined by the input points, and to perform image processing of reducing at least one of brightness and definition of the medical image in a remaining area except for an area of the window.
