Methods of image correction formed on horizontal long paths

Abstract

The possibilities of forming optical images on horizontal extended atmospheric paths are explored. Two different methods for improving image quality are analyzed. It is known that at the present time the solution of the problem of long-range vision with super-high resolution is conducted along several independent lines, firstly, on the development of methods based on the classical technique of adaptive optics, i.e., by correcting the distorted wavefront itself, and, secondly, on the use of digital post-detection techniques, as well as, on the way to attract purely engineering solutions. These methods are applied, both for terrestrial systems, and for astronomical instruments. They can be instrumental (for example, adaptive correction, the use of polarization filters, receiver gating, etc.), mixed (adaptive correction and subsequent processing of images on computers or special processors) or program-algorithmic only. The analysis is carried out for systems operating on horizontal paths. This, first of all, is due to the fact that any horizontal path by the strength of turbulence far exceeds any astronomical one. On extended horizontal paths, in addition to phase distortions that cause the effects of jitter and blurring of the image, there are fluctuations in the intensity of the received radiation, which leads to the appearance of flickering effects of the image, as well as to the manifestation of ambiguity in describing the phase distortions of the optical wave. Numerical and analytical calculations are performed. Experiments were carried out on the atmospheric paths from 160 m to 3.2 km long in city conditions.