Passive optical methods in measurement of the structure parameter of the air refractive index

A passive optical method for estimating the level of atmospheric turbulence (structure parameter of the air refractive index C n 2 ) from the image jitter is considered. It is proposed to use a high-speed digital video camera and effective two-dimensional parallel algorithms of image processing for measuring C n 2 in real time. Results obtained by the active and passive optical methods, as well as by an acoustic method, are compared.