Avian surface reconstruction in free flight with application to flight stability analysis of a barn owl and peregrine falcon
Avian surface reconstruction in free flight with application to flight stability analysis of a barn owl and peregrine falcon
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DOI：
10.1242/jeb.185488
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发表时间：
2019-05-01
影响因子：
2.8
通讯作者：
Windsor, Shane P.
中科院分区：
文献类型：
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作者：
Durston, Nicholas E.;Wan, Xue;Windsor, Shane P.
鸟类主要通过改变翅膀和尾巴的形状和方向来创造和控制飞行所需的力量。它们的机翼几何形状的特点是参数的复杂变化，如弧度、扭转、后掠角和二面体。为了表征这种复杂性，开发了一种多视图立体摄影测量装置，用于在自由飞行期间以高分辨率精确测量表面几何形状。利用鸟类的自然图案作为基于相位相关的图像匹配的基础，在不干扰鸟类的情况下，允许室内或室外使用。该方法的精度被量化，并表明足以表征感兴趣的几何参数，但在接近翼缘和一些局部区域的精度降低。为了证明该方法的实用性，给出了仓鸮（Tyto alba）和游隼（Falco peregrinus）在每只鸟滑翔飞行的三个瞬间的表面重建。仓鸮以一致的几何形状飞行，具有正翼弧度和纵向四面体。根据飞行动力学理论，这表明在这些飞行中它是纵向静态不稳定的。游隼以一致的滑翔角度飞行，但在不同几何形状的空气速度范围内飞行。与仓鸮不同，它的滑翔结构没有提供纵向静态稳定/不稳定的明确指示。这两种鸟所采用的几何形状似乎与控制校正有关，这种方法将非常适合未来在这一领域的调查，以及鸟类飞行动力学的其他定量研究。
Birds primarily create and control the forces necessary for flight through changing the shape and orientation of their wings and tail. Their wing geometry is characterised by complex variation in parameters such as camber, twist, sweep and dihedral. To characterise this complexity, a multi-view stereo-photogrammetry setup was developed for accurately measuring surface geometry in high resolution during free flight. The natural patterning of the birds was used as the basis for phase correlation-based image matching, allowing indoor or outdoor use while being non-intrusive for the birds. The accuracy of the method was quantified and shown to be sufficient for characterising the geometric parameters of interest, but with a reduction in accuracy close to the wing edge and in some localised regions. To demonstrate the method's utility, surface reconstructions are presented for a barn owl (Tyto alba) and peregrine falcon (Falco peregrinus) during three instants of gliding flight per bird. The barn owl flew with a consistent geometry, with positive wing camber and longitudinal anhedral. Based on flight dynamics theory, this suggests it was longitudinally statically unstable during these flights. The peregrine falcon flew with a consistent glide angle, but at a range of air speeds with varying geometry. Unlike the barn owl, its glide configuration did not provide a clear indication of longitudinal static stability/instability. Aspects of the geometries adopted by both birds appeared to be related to control corrections and this method would be well suited for future investigations in this area, as well as for other quantitative studies into avian flight dynamics.