Rupnik Ewelina, Jansa Josef, Pfeifer Norbert
Department of Geodesy and Geoinformation, Technische Universität Wien, Gusshausstrasse 27-29, Vienna 1040, Austria.
Sensors (Basel). 2015 Dec 5;15(12):30784-809. doi: 10.3390/s151229828.
The objective of the work is to model the shape of the sinusoidal shape of regular water waves generated in a laboratory flume. The waves are traveling in time and render a smooth surface, with no white caps or foam. Two methods are proposed, treating the water as a diffuse and specular surface, respectively. In either case, the water is presumed to take the shape of a traveling sine wave, reducing the task of the 3D reconstruction to resolve the wave parameters. The first conceived method performs the modeling part purely in 3D space. Having triangulated the points in a separate phase via bundle adjustment, a sine wave is fitted into the data in a least squares manner. The second method presents a more complete approach for the entire calculation workflow beginning in the image space. The water is perceived as a specular surface, and the traveling specularities are the only observations visible to the cameras, observations that are notably single image. The depth ambiguity is removed given additional constraints encoded within the law of reflection and the modeled parametric surface. The observation and constraint equations compose a single system of equations that is solved with the method of least squares adjustment. The devised approaches are validated against the data coming from a capacitive level sensor and on physical targets floating on the surface. The outcomes agree to a high degree.
这项工作的目标是对实验室水槽中产生的规则水波的正弦形状进行建模。这些波随时间传播，呈现出光滑的表面，没有白帽或泡沫。提出了两种方法，分别将水视为漫反射表面和镜面反射表面。在任何一种情况下，都假定水呈行波正弦波的形状，从而将三维重建任务简化为求解波参数。第一种设想的方法纯粹在三维空间中执行建模部分。通过光束平差在单独的相位中对各点进行三角测量后，以最小二乘法将正弦波拟合到数据中。第二种方法为从图像空间开始的整个计算工作流程提供了一种更完整的方法。水被视为镜面反射表面，移动的镜面反射是相机唯一可见的观测结果，这些观测结果特别是单幅图像。给定反射定律和建模参数曲面中编码的附加约束，深度模糊性得以消除。观测方程和约束方程构成一个方程组，用最小二乘法平差法求解。所设计的方法针对来自电容式液位传感器的数据以及漂浮在水面上的物理目标进行了验证。结果高度一致。
