6. Atmospheric and optical turbulence

In this chapter, we will study the consequences of atmospheric turbulence on the operation of an optical sensor, and in particular on image quality. This is an interesting example of "random process transformation", because :

• the physical phenomenon at the origin of the image disturbances, atmospheric turbulence, is modeled as a random process whose support is four-dimensional, three spatial dimensions and one temporal dimension, and the resulting process (the image disturbances) is itself three-dimensional (two spatial dimensions of the image and the temporal dimension);

• several intermediate stages must be analyzed: from atmospheric turbulence to fluctuations in the air's refractive index, then to variations in the optical paths through the turbulent layer, to variations in the electromagnetic signal arriving...