基于BOS技术的气动光学流场传输效应成像偏移校正方法研究

Investigation on correction method of aero-optical transmission effects imaging deviation based on BOS technique

  • 摘要: 高速成像制导导弹在大气中飞行时,受到气动光学效应的影响,目标成像位置与其实际位置之间出现偏差。实现对气动光学效应成像偏移校正,对于提高制导精度意义重大。气动光学效应成像偏移具有很强的随机性和非线性,校正起来十分困难。通过利用背景纹影技术测量光线穿过变折射率场后的光线偏移量,建立畸变图像与参考图像之间的控制点对,采用局部加权平均拟合方法构建用于图像校正的映射函数,利用双三次卷积方法对图像灰度值进行重采样处理,完成对畸变图像的校正。分别对固定相位物(透镜)和喷流马赫数3.0的超声速气膜引起的成像偏移进行校正,实验结果验证了校正方法的有效性。

     

    Abstract: When high-speed imaging guidance missile was flying in the atmosphere, which was affected by aero-optical effect, and then the imaging target position was different from the actual position. It was difficult for aero-optical imaging deviation to be corrected, due to the very strong random and nonlinear characteristic. The deviation of light rays passing through a variable refractive index field was measured based on Background Oriented Schlieren (BOS), the control points between the distortion image and reference image (undistorted image) were built, local weighted mean fitting method was adopted to construct the mapping function for the image correction, and bi-cubic convolution method was used to resample the image gray value, the distortion images were corrected at last. The imaging deviations caused by the stationary phase (lens) and the jet Mach number 3.0 supersonic film were corrected partly, and the validity of the correction method is confirmed by the experimental results.

     

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