Application of Forward-Scan Sonar Stereo for 3-D Scene Reconstruction
Application of Forward-Scan Sonar Stereo for 3-D Scene Reconstruction
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DOI：
10.1109/joe.2018.2875574
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发表时间：
2020-04-01
影响因子：
4.1
通讯作者：
Negandaripour, Shahriar
中科院分区：
文献类型：
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作者：
Negandaripour, Shahriar
新一代水下2-D前视声纳摄像机工作在接近和超过1-MHz的频率提供图像与增强的目标细节。在其仅为数十米的有限范围内，它们是在混浊沃茨中执行视觉引导任务的最合适的成像系统。这些包括但不限于检查水下结构以进行日常维护、搜索和监视，探测、定位和识别小型目标，以及基于目标的定位和导航。为此，在许多这样的操作中，3-D目标形状的自动3-D重建和建立感兴趣点的3-D空间位置是高度期望的能力。如利用2-D光学图像所实现的，可以利用来自附近位置的多个图像。本文探讨了3-D点的位置估计从两个重叠的图像收集与两个前向扫描（FS）声纳系统的立体配置，或与一个FS声纳在已知的相对姿态，建立从视觉运动线索。第一个贡献包括声纳立体核线几何的分析。除了将对应问题简化为沿沿着极线的1-D搜索之外，这还揭示了与距离和方位角的声纳测量相关联的独特性质。接下来，某些线性封闭形式的重建解决方案，建立其退化，并提出退化条件下的调整。退化和非退化立体声配置的两个首选方法确定：正则化为基础的方法和一个采用范围约束近似，分别。这些主要提供了基于梯度下降的迭代非线性优化方案的初始估计。最后，合成数据的实验结果，以评估各种估计方法，并与真实的数据集，以证明在两个海底操作场景下的性能。
New generation of underwater 2-D forward-look sonar video cameras operating at near and over 1-MHz frequency offer images with enhanced target details. Within their limited range of only tens of meters, they are the most suitable imaging systems for conducting visually guided missions in turbid waters. These include, but are not limited to inspecting underwater structures for routine maintenance, search, and surveillance, the detection, localization, and identification of small sought after objects, as well as target-based positioning and navigation. To this end, the automatic 3-D reconstruction of 3-D target shape and establishing the 3-D spatial location of interest points are highly desired capabilities in many such operations. As achieved with 2-D optical images, multiple images from nearby positions may be utilized. This paper investigates the estimation of 3-D point locations from two overlapping images collected with two forward-scan (FS) sonar systems in stereo configuration, or with one FS sonar at known relative poses, established from visual motion cues. The first contribution includes the analysis of a sonar stereo epipolar geometry. Beyond reducing the correspondence problem to a 1-D search along epipolar curves, this reveals unique properties associated with sonar measurements of range and azimuth angle. Next, certain linear closed-form reconstruction solutions are presented, their degeneracies are established, and adjustments under degenerate conditions are proposed. Two preferred method for the degenerate and nondegenerate stereo configurations are identified: a regularization-based method and one employing a range constraint approximation, respectively. These primarily provide the initial estimate for an iterative nonlinear optimization scheme based on gradient descent. Finally, the results of experiments with synthetic data are presented to assess various estimation methods, and with real data sets to demonstrate performance under two subsea operational scenarios.