纹影成像法与密度可视化  

Schlieren photography and density visualization

作　　者：董家豪 徐乾 余智君 王思慧[1] 周惠君[1] DONG Jia-hao;XU Qian;YU Zhi-jun;WANG Si-hui;ZHOU Hui-jun(School of Physics,Nanjing University,Nanjing 210093,China)

机构地区：[1]南京大学物理学院,江苏南京210093

出　　处：《物理实验》2020年第3期51-54,59,共5页Physics Experimentation

摘　　要：纹影法可以测量气体微小密度的变化,传统纹影方法基于几何光学的折射定律,依赖图像灰度与偏转角之间的定标关系,在实际测量使用中较为局限.对传统方法进行改进,采用傅里叶光学的分析方法,光源取为相干光,观测火焰密度场,在像屏上得到了明暗条纹分布.理论演算表明,像屏上的明暗条纹反映了密度场的相位分布,由此可以推演出密度分布.实验所采用的方法无需借助定标关系,更具有普适性.Schlieren photography was a method to measure subtle changes of the density of gas.Traditional schlieren photography was based on the refraction law in geometrical optics,relying on scaling relation between the gray levels of image and the deflection angle,which limited its application.In the present work,Fourier optics was applied to the optical field.Coherent light was used as the light source and the fringelike pattern was obtained in the screen.Theoretical analysis showed that the fringelike pattern corresponds to the phase distribution of the density field,and the density distribution could be calculated.This method was more universal since the scaling relation was not needed.

关 键 词：纹影成像法 傅里叶光学 密度场重建 

分 类 号：O438.2[机械工程—光学工程]