多源数据融合的城市三维实景建模

随着数字城市以及智慧城市的提出,城市模拟从二维发展到三维,对城市三维实景建模的要求越来越高。由于城市地物密度高、变化快,传统的手工三维建模方法效率低,无法适应快速发展变化的城市环境,因此,往往采用无人机倾斜摄影技术进行快速三维建模,但无人机倾斜摄影方法无法解决城市地物遮挡、树冠遮挡、屋檐遮挡、玻璃透光等问题,造成三维模型局部纹理扭曲、地物拉花、地物空洞等缺陷,在模型精度、质量、应用方面存在诸多问题。为了解决上述问题,以中国科学院大学为研究区,运用无人机倾斜摄影技术与地面激光雷达技术进行融合建模。在实验过程中,外业采用“规则航线自动拍摄为主,兴趣区手动拍摄为辅”的无人机影像获取策略;内业则利用“手动粗配准,ICP算法精配准”的方法将地面雷达点云统一到无人机影像坐标系统中。实验结果表明,多源数据融合的方法既能够保证三维建模的效率,又能够修正无人机单独建模模型的地物扭曲、空洞等问题,提高模型的精度,优化城市三维模型。

City 3D real-world modeling based on multi-source data fusion

With the development of digital cities and smart cities, urban simulation has developed from two-dimensional to three-dimensional. Urban three-dimensional real-world modeling becomes more and more challenging. Due to the high density and rapid change of urban features, traditional manual 3D modeling methods are inefficient and cannot adapt to the rapidly changing urban environment. Therefore, UAV tilt photography technology is often used for fast 3D modeling. However, UAV tilt photography method cannot solve the problems of urban object occlusion, canopy occlusion, eaves occlusion, glass light transmission, etc., resulting in defects in the 3D model, such as local texture distortion, object pulling, and object voids. To dealing with these issues, taking the campus of University of Chinese Academy of Sciences as the research area, a fusion modeling method was proposed by combining the UAV tilt photography technology with ground LIDAR technology. In the experiment, a drone image acquisition strategy of "regular route mainly automatic shooting-based, supplemented by interest area with manual shooting" was used in the field; in interior work, "manual coarse registration and ICP algorithm fine registration" was used. The experimental results show that the method of multi-source data fusion can not only ensure the efficiency of 3D modeling, but also solve the problems of ground distortion and holes in the UAV alone modeling method, improving the accuracy of the model, and optimizing the 3D model of the city.