Abstract: Provided are a method and system for extracting a target object from a background image, the method including: generating a scalar image of differences between the object image and the background, using a lightness and a color difference between the background and current video frame; initializing a mask to have a value equal to a value for a corresponding pixel of a mask of a previous video frame, where a value of the scalar image of differences for the pixel is less than a threshold, and to have a predetermined value otherwise; clustering the scalar image of differences and the depth data; filling the mask for each pixel position the current video frame, using a centroid of a cluster of the scalar image of differences and the depth data; and updating the background image on the basis of the filled mask and the scalar image of differences.