Constructing a 3D trunk model from two images

Trees stand for a key component in the natural environment, thus modeling realistic trees has received much attentions of researchers in computer graphics. However, most trees in computer graphics are generated according to some procedural rules in conjunction with some random perturbations, thus they are generally different from the real trees in the natural environment. In this paper, we propose a systematic approach to create a 3D trunk graphical model from two images so that the created trunk has a similar 3D trunk structure to the real one. In the proposed system, the trunk is first segmented from the image via an interactive segmentation tool and its skeleton is then extracted. Some points on the skeleton are selected and their context relations are established for representing the 2D trunk structure. A camera self-calibration algorithm appropriate for the two-view case is developed, and a minimum curvature constraint is employed to recover the 3D trunk skeleton from the established 2D trunk structure and the calibrated camera. The trunk is then modeled by a set of generalized cylinders around the recovered 3D trunk skeleton. A polygonal mesh representing the trunk is finally generated and a textured 3D trunk model is also produced by mapping the image onto the surface of the 3D trunk model. We have conducted some experiments and the results demonstrated that the proposed system can actually yield a visually plausible 3D trunk model which is similar to the real one in the image.