Speckle-beam oriented schlieren technique
Speckle-beam oriented schlieren technique
复制标题
散斑光束定向纹影技术
DOI：
10.1007/s00348-020-03113-3
复制
发表时间：
2021
影响因子：
2.4
通讯作者：
Akihiro SASOH
中科院分区：
文献类型：
--
作者：
Yusuke NAKAMURA;Takumi SUZUKI;Kiyoshi KINEFUCHI;Akihiro SASOH
背景定向纹影(BOS)技术是近年来发展起来的一种测量透明介质折射角分布的新方法，被称为散斑纹影技术。散斑图案是通过使相干激光束通过全息漫射器、针孔和透镜来产生的，从而产生直接投射到图像传感器上的准直背景图像。由于背景图像的强度保持在高水平，该方法原则上对于诊断快速和/或低信噪比现象是有用的，例如具有辐射发射的高温气体。此外，通过将背景光束分成两个不同焦距的成像路径，可以测量位置不确定的纹影物体的折射角，并可以确定折射角的深度位置。通过测量不同注入位置的声速射流中的折射角和深度位置分布，验证了这一技术。
AbstractAn advanced background-oriented schlieren (BOS) method, named as the speckle beam-oriented schlieren technique, was newly developed to measure the distribution of refraction angles in transparent media. A speckle pattern is generated by passing a coherent laser beam through a holographic diffuser, a pinhole, and a lens, generating a collimated background image that is projected directly onto the image sensors. Since the intensity of the background image is maintained at a high level, this method is, in principle, useful for diagnosing fast and/or low signal-to-noise phenomena, such as high-temperature gasses with radiation emission. Moreover, by splitting the background beam into two imaging paths with different focal lengths, the refraction angles can be measured for a schlieren object with uncertain location, and the depth position of the refraction angles can be resolved. This technique was demonstrated by measuring the refraction angle and the depth position distribution in a sonic jet with different injected locations.Graphic abstract