1. An image processing system comprising: an image input unit for inputting images photographed respectively by a plurality of cameras provided to photograph a photographing target region at a plurality of angles; a depth information calculating unit for calculating, every pixel, depth information representing distances from the cameras of moving objects included in a plurality of photographed images input by the image input unit; a 3D information generating unit for setting a plurality of projection planes in adaptation to a relative angular relationship between the cameras and projecting values of each of pixels of the moving objects included in the photographed images input by the image input unit in directions of the projection planes corresponding to the respective photographed images in accordance with the depth information, thereby generating 3D information obtained by synthesizing, into one, the moving objects included in the photographed images; an overlooking image generating unit for synthesizing the 3D information of the moving object generated by the 3D information generating unit with a space image representing a space of the photographing target region, thereby generating an overlooking image of the photographing target region; and a display control unit for displaying, on a display, the overlooking image generated by the overlooking image generating unit.