倾斜影像自动空三及其在城市真三维模型重建中的应用

Oblique Image Based Automatic Aerotriangulation and Its Application in 3D City Model Reconstruction

在一种具有视点不变性的改进的倾斜影像自动匹配方法的基础上,针对多视倾斜影像光束法平差方法中未知参数多的问题(例如可能导致平差解算不稳定),提出了带有相对姿态参数的倾斜影像光束法平差模型,并给出了该模型的适用范围。对一套典型的数字倾斜摄影仪SWDC-5的倾斜影像数据进行实验,结果表明:当相机之间曝光延迟小,且相对姿态参数可以看作比较严格的刚体时,该方法的自动空中三角测量(简称空三)处理精度较高,单位权中误差为0.46像素,像点平均残差为0.27像素。将该空三成果应用到城市真三维模型重建中,计算机自动得到的三维表面模型纹理比较自然、真实,能够满足一定程度的视觉需求,为大规模城市真三维模型重建提供了参考。

In this paper,we proposed an automatic aerotriangulation method based on SWDC-5oblique images.First of all,we designed an improved viewpoint-invariant matching method for oblique images based on the perspective transformation.Secondly,in order to reduce the amount of unknown adjustment parameters（overmuch unknown adjustment parameter may weaken the instability of adjustment solution）,we offered a new bundle adjustment model for oblique images which took the relative attitude parameters of cameras into account,and also gave the application scope of the model.Experiments conducted on the typical SWDC-5oblique images demonstrated that when the relative attitude of cameras（on same camera station）are stable and their cameras exposure are limited within a short time delay,the aero-triangulation accuracy of our method is high,the unit weight error is 0.46 pixels and the average residual of image points is 0.27 pixels.Thirdly,we applied the results of aero-triangulation to PMVS（patch-based multi-view stereo matching）algorithm to gain the dense point-cloud of the experimental city,used screened Poisson reconstruction algorithm to get its 3D mesh,and reconstruct its 3Dsurface with 3Dtexture algorithm.Experiments showed that the accuracy of the aero triangulation met the requirements of applications,and the obtained 3Dcity model had a natural,real texture,all this proved that the idea of automatic reconstruction of 3Dcity model is feasible and made agood reference for the large-scale 3Dcity model reconstruction.