1. An apparatus for separating an image into a foreground and a background, the apparatus comprising: an edge image generating unit which generates an edge image of a current image, wherein the current image includes a background and a foreground; a background edge model renewing unit which renews a background edge model of a previous image based on the generated edge image of the current image; and a foreground edge extracting unit which generates a foreground edge image based on the generated edge image and the renewed background edge model, wherein if a pixel is an edge pixel of the edge image of the current image, the background edge model renewing unit increases a pixel value of a corresponding pixel of the background edge model of the previous image by a first predetermined value, and wherein if the pixel is a non-edge pixel of the edge image of the current image, the background edge model renewing unit decreases the pixel value of the corresponding pixel of the background edge model of the previous image by a second predetermined value.