1. An apparatus for extracting an object comprising: an image receiver configured to receive an image; a coupled saliency-map generator configured to generate a coupled saliency-map which is the sum of the product of a global saliency-map of the image and a predetermined weight value and a local saliency-map; an adaptive tri-map generator configured to generate an adaptive tri-map corresponding to the coupled saliency-map; an alpha matte generator configured to generate an alpha matte based on the adaptive tri-map; and an object detector configured to extract an object according to transparency of the alpha matte to generate an object image.