1. A method for modeling and registering 3D scene structure based on a single image, comprising: collecting image data with a general camera; calibrating the camera with line features in the collected image, and performing plane-support characteristic analysis on the basis thereof, so as to preliminarily obtain information of scene structure in the image; then forming a scene image via user interoperation, and generating a final 3D scene structure from the scene image; and finally registering the obtained 3D scene structure in a unified 3D scene by using characteristic of a directed line segment, completing reconstruction of wide-range 3D scene structure under perspectives of multiple cameras, characterized by steps of: (1) collecting the image data with the general camera, extracting the line features in the image, grouping the line features and calculating vanishing points by adopting components expectation maximization iteration technology, and calibrating the camera with directional features of the vanishing points; (2) performing plane support characteristic analysis by using the categorized lines, so as to obtain planes to which each pixel in the image belongs, and segmenting the image according to the planes to which the pixels belong, in order to obtain preliminary information of the scene structure; (3) extracting and constructing a scene image of the image from the preliminary information of the scene structure via user interoperation, continuously optimizing the scene image in the course of the interoperation, and generating a final 3D scene structure based on the scene image; and (4) registering the obtained 3D scene structure into the unified 3D scene by using characteristic of a single directed line segment, so as to extend modeling of the 3D scene structure under the perspective of a single camera to a larger scale.