The effect of random phase variation of turbulence on image resolution

The turbulence produced by the shearing process between the cooling gas and atmosphere of a hypersonically moving vehicle, which contributes to the image degradation, is addressed. Based on the random phase variation of the optical wavefront, the modulation transfer function (MTF) can be specified to characterize the effect of turbulence on the image resolution. The use of computer simulation to generate the random phase variation and variance and the corresponding MTF is reported. Different types of phase variation are investigated. The MTF for each case is used to find the effect on image degradation and resolution. The effect of the nonuniform turbulence intensity across the optical window is also investigated and compared with results for the uniform case.