1. An image processing device to extract a foreground moving object from a depth map of a three-dimensional (3D) image, the device comprising: an image depth map acquirer to obtain the depth map of a successive 3D image, wherein the depth map expresses feature information of a target in the 3D image and comprises a two-dimensional (2D) pixel matrix sign of the 3D image; and a moving object segmenter to segment a moving object from the obtained depth map; construct a background model using the obtained depth map and determine an initial seed point of a foreground object; obtain a foreground object region by performing region growing from the initial seed point; obtain an initial region of the moving object by merging foreground object regions belonging to the same moving object among obtained foreground object regions; and obtain a complete region of the moving object by performing precise segmentation on adjacent initial regions of the moving object exhibiting a complex motion.