Coordination Funds

在大地形变分析中，一致性调查在统计上测试两个或多个对象状态的几何变化。需要对重要性进行严格评估，以区分几何变化与测量和数据处理方法的不确定性。在当前技术状态下，变形分析依赖于由例如全站仪、GNSS或延伸仪获取的基于点的测量。这些单独的点的预选，应该是对象的特征，属于工程师的责任。总体而言，这一选择需要跨学科合作。在分析了这些点的运动后，通过空间泛化过程得到了整个物体的运动。地面激光扫描(TLS)已经是一种成熟的现实捕捉方法。对于严格的变形分析，到目前为止，它很少被使用。基于TLS的变形分析的最大优势是以高空间分辨率的结果点云对对象进行采样。因此，可以省略带有单个点的主观对象离散化，从而导致更客观的分析。然而，为了使用TLS进行变形分析，需要解决几个挑战。这些挑战与前面提到的对小测量不确定度和严格的重要性调查的需求密切相关，这些需求需要完全确定的不确定度预算。挑战在于：·需要测量对象表面的表面表示，该表面表示允许表示对象细节以及引入光滑度假设。此外，个别参数的变化应可与个别--如果可能的话--空间受限--变形相联系。·校准激光扫描仪，以便将系统仪器误差降至最低。·确定TLS测量的实际协方差矩阵。·量化因测量对象表面的表面表示中的偏差而产生的模型不确定性，因为该表示仅近似于真实表面。·通过无分布不确定性建模的概念补充TLS测量的随机模型和建模不确定性，以按集合和间隔考虑剩余的系统误差。·分割变形的和未变形的点云部分，并可靠地确定激光扫描的大地基准，以便在一致的坐标系中准确转换不同的激光扫描。·分析变形分析的敏感度，以确定最佳测量几何形状和扫描仪设置，以便尽早、尽可能可靠地检测变形。这个拟议的研究单位旨在解决这些挑战，以便为使用最小二乘法进行变形分析作出重大贡献。所取得的成果将可推广到其他基于区域的测量技术中。

Within geodetic deformation analyses, congruency investigations statistically test geometric changes of two or more object states. A rigorous assessment of significance is needed to separate between geometric changes and the uncertainty of measurements and data processing methods. Within the current state of the art, the deformation analysis rests upon point-based measurements, acquired by e.g. total stations, GNSS or extensometers. The preselection of these individual points, that should characterize the object, falls into the responsibility of the engineer. In general, this selection demands interdisciplinary collaboration. After analyzing the movement of these individual points, the movement of the complete object is gained by a spatial generalization process. The terrestrial laser scanning (TLS) is already an established method for reality capture. For rigorous deformation analyses, it has been used only rarely so far. The great advantage of TLS-based deformation analyses is that the object is sampled with a high spatial resolution of the resulting point cloud. Thus, the subjective object discretization with individual points can be omitted, leading to more objective analyses. Nevertheless, in order to use TLS for deformation analyses, several challenges need to be solved. These challenges are closely related to the previously mentioned demand on small measurement uncertainties and strict significance investigations that need an entirely determined uncertainty budget. The challenges are: • A surface representation of the measured object surface is needed that allows for representing object details as well as for introducing smoothness assumptions. Additionally, changes in individual parameters should be connectable to individual –if possible spatially limited– deformations. • Calibrating the laser scanner so that systematic instrumental errors are minimized. • Determining a realistic covariance matrix of the TLS measurements. • Quantifying the model uncertainty that originates from deviations in the surface representation of the measured object surface since this representation only approximates the real surface. • Complement the stochastic model of TLS measurements and model uncertainty by concepts for distribution-free uncertainty modelling to take remaining systematic errors into account by sets and intervals. • Segmentation of deformed and non-deformed parts of the point cloud and robust determination of the geodetic datum for the laser scans to accurately transform different laser scans in a consistent coordinate frame. • Analyzing the sensitivity of the deformation analysis to determine optimal measurement geometries and scanner settings so that deformations can be detected as early and as reliably as possible. This proposed research unit aims at solving these challenges to make a substantial contribution to using TLS for deformation analyses. The gained findings will be transferable to other area-based measurement techniques.