基于纹影剪切干涉法测量空气折射率、密度和温度的梯度

Measurement of air refractive index,density and temperature gradient based on schlieren shear interferometry

基于纹影法提出了一种二维剪切干涉法并设计其装置,该方法通过分析相位变化得到空气折射率梯度。分别对光束在水平方向和竖直方向进行剪切,产生相互垂直的干涉条纹。然后将采集到的干涉图像进行滤波、二值化和条纹细化处理,分别求得竖条纹位移量和横条纹位移量,进而得到两个方向的空气折射率梯度、空气密度梯度,以及在特定大气压强下的温度梯度。通过纹影二维剪切干涉法设计的成像系统简单新颖,保证精确度的同时又能稳定测量空气的二维梯度信息。

Based on schlieren method,a two-dimensional shear interference method is proposed and a device is designed in this paper.In this method,the air refractive index gradient is obtained by analyzing the phase change.We shear the beam in the horizontal direction and the vertical direction respectively to produce mutually perpendicular interference fringes.Then the interference images are processed by filtering,binarization and fringe thinning.The vertical fringe displacement and the horizontal fringe displacement are obtained respectively,and then the air refractive index gradient,the air density gradient and the temperature under a specific atmospheric pressure are obtained.The imaging system designed by schlieren two-dimensional shear interferometry is simple and novel,and can be used to measure the two-dimensional gradient information of air.