For Three-dimensional Laser Scanning, Realistic Texture Mapping Technology Research

With the rapid development of 3D laser scanning technology, the creation of photorealistic 3D models using range image and digital photographs is becoming increasingly popular in a wide range of fields, such as Reverse Engineering, Virtual Reality, Digital Library and Digital City. High precision geometry information and realistic texture details are two main aspects of realistic 3D models, but the latter hasn't attracted enough attention as the former.Realistic texture mapping technique is particularly important for constructing photorealistic 3D models. In this paper, the problem of texture mapping for reconstruction of 3D models is studied and solved based on principles of texture mapping and lighting theory. The primary work of this paper includes:(1) The theory and technology of reconstruction of 3D models are discussed, with the 3D laser scanner in our laboratory as an example. Then the adverse effects in texture mapping resulting from illumination conditions of the texture images are presented: discontinuity and shadow in model's texture images when they're taken with cameras;(2) The illumination consistency technology is researched. A two-step correction algorithm for illumination effects in texture images is given. Firstly, a global correction is applied to reduce the obvious difference between texture images caused by different illumination conditions, and then a local correction is done to eliminate the seams near the border of two texture images;(3) To remove the shadows in the texture images, an improvement of shadow removal algorithm simply based on image is applied, and then the result is refined based on model.The above algorithms are realized on the platform VC++ and OpenGL, tested with the data acquired by our laser scanner, and finally proved valid by experimental results.