The principle and characteristics of an image fibre Background Oriented Schlieren (Fibre BOS) technique for time-resolved three-dimensional unsteady density measurements
The principle and characteristics of an image fibre Background Oriented Schlieren (Fibre BOS) technique for time-resolved three-dimensional unsteady density measurements
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DOI：
10.1007/s00348-021-03251-2
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发表时间：
2021-07
影响因子：
2.4
通讯作者：
Takahiro Ukai
中科院分区：
文献类型：
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作者：
Takahiro Ukai
图像纤维背景纹影(Fibre Back Oriented Schlieren，Fibre BOS)技术在时间分辨定量三维非定常密度测量中具有成本效益、便携性和灵活性等方面的优势。光纤BOS技术具有这些优点的原因是，可以同时使用柔性光学图像光纤而不是昂贵的高速相机，以几个投影角度来可视化透明介质，这是层析重建所需的。本研究对光纤BOS技术的性能进行了基础性和示范性实验研究。当背景点尺寸大于作为图像光纤的组件的芯的两倍时，如果芯尺寸大于图像传感器上的像素尺寸，则偏转角度的估计精度被提高。用一台摄像机可以同时捕捉到从几个投影角穿过图像纤维的多幅图像，并且可以测量到非定常复杂流动的时间变化。光纤BOS技术具有使用单个高速相机进行高时间分辨率三维非稳态密度测量的潜力。
An image fibre Background Oriented Schlieren (Fibre BOS) technique has an advantage in cost-effectiveness as well as portability and flexibility for a time-resolved quantitative three-dimensional unsteady density measurement. The reason why the Fibre BOS technique has these advantages is that a transparent medium can be visualized at several projection angles, which are required for a tomographic reconstruction, using the flexible optical image fibres instead of expensive high-speed cameras, simultaneously. The basic and demonstration experiments were conducted to investigate the performances of the Fibre BOS technique in this study. The estimation accuracy of a deflection angle is increased when a background-dot size is more than twice as large as a core which is the component of the image fibre if the core size is larger than a pixel size on an image sensor. Multiple images going through the image fibres from several projection angles are simultaneously captured using a single camera, and temporal variation of an unsteady complex flow is measurable. The Fibre BOS technique has a potential to conduct the high time-resolved three-dimensional unsteady density measurement using a single high-speed camera.Graphic abstract