Quantifying impacts on remote photogrammetric inspection using unmanned aerial vehicles
Quantifying impacts on remote photogrammetric inspection using unmanned aerial vehicles
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DOI：
10.1016/j.engstruct.2019.109940
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发表时间：
2020-04-15
影响因子：
5.5
通讯作者：
Pierce, Gareth
中科院分区：
文献类型：
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作者：
Zhang, Dayi;Watson, Robert;Pierce, Gareth
远程摄影测量检测是一种无损检测方法，用于量化表面完整性和检测外部不连续性。无人机（UAV）的机动性和尺寸为快速部署大型资产的远程摄影测量检查提供了灵活性。在本文中，摄影测量检查的结果作为一个三维轮廓，从无人机捕获的图像重建。实验是在室内进行的，使用的风力涡轮机叶片部分，从最近退役的资产。代表环境磨损的自然发生的表面特征增加了少量的人工特征，以帮助检查质量的可视化。一个自主的无人机系统的摄影测量检查和图像参数的影响，如环境光水平，运动模糊和焦点模糊量化的检查精度的影响。在所研究的参数值的范围内，观察到最差的情况下，重建误差的退化因子为13，而不是最佳的。重建质量时，采用激光测距扫描仪，以保持间隔距离相对于飞行过程中的对象也进行了研究。在该方案中，控制器自动生成实时自适应飞行路径，以遵循风力涡轮机叶片的外部轮廓，因此，在具有复杂几何形状的物体的近距离检查期间证明了图像质量的改善。使用摄影测量重建的误差相比，使用独立的计量设备获得的模型进行量化的检查精度。当使用基于激光的自适应路径时，与预先计算的圆形路径相比，重建几何形状中的误差减少了2.7倍。在最佳情况下，平均偏差低于0.25 mm。在纹理化的3D重建轮廓中，可以清楚地观察到风力涡轮机叶片损坏的可能性，例如边缘破碎、表面缺陷、早期前缘侵蚀。表明成功的检查过程的效用。本文的研究结果评估了光学环境效应对摄影测量检测精度的影响，为减轻负面影响提供了实用的见解。
Remote photogrammetric inspection is a Non-Destructive Testing method used to quantify surface integrity and detect external discontinuities. The mobility and size of an unmanned aerial vehicle (UAV) offer the flexibility to quickly deploy remote photogrammetric inspections for large-scale assets. In this paper, the results of a photogrammetric inspection are presented as a 3D profile, reconstructed from UAV captured images. Experiments were conducted indoors using a wind turbine blade section obtained from a recently decommissioned asset. The naturally occurring surface features representative of environmental wear were augmented with a small number of artificial features to aid in the visualisation of inspection quality. An autonomous UAV system for photogrammetric inspections is demonstrated and the influence of image parameters such as environmental light levels, motion blur and focal blur quantified in terms of their impact on the inspection accuracy. Over the range of parameter values studied, the poorest scenario was observed to cause a degradation in reconstruction error by a factor of 13 versus the optimal. Reconstruction quality when employing a laser range scanner to maintain standoff distance relative to the object during flight was also investigated. In this schema, the controller automatically generated a real-time adaptive flight path to follow the outer profile of the wind turbine blade and, consequently, demonstrated improved image quality during close-range inspection of an object with complex geometry. Inspection accuracy was quantified using the error of the photogrammetric reconstruction as compared to a model acquired using independent metrology equipment. While utilising the laser-based adaptive path, error in the reconstructed geometry was reduced by a factor of 2.7 versus a precomputed circular path. In the best case, the mean deviation was below 0.25 mm. Instances of wind turbine blade damage such as edge crushing, surface imperfections, early stage leading edge erosion were clearly observed in the textured 3D reconstruction profiles, indicating the utility of the successful inspection process. The results of this paper evaluate the impact of optical environmental effects on photogrammetric inspection accuracy, offering practical insight towards mitigation of negative effects.