Imaging Through Turbulence in the Atmosphere

This chapter discusses imaging through turbulence in the atmosphere. Turbulent velocity fluctuations in the propagation medium cause image distortion by generating a statistical temperature field, which gives rise to random inhomogeneities in the index of refraction. Imaging through turbulent media is of importance in optical and radio astronomy, remote sensing, target identification, and the investigation of the properties of the medium itself. The chapter also discusses the current state of understanding of the propagation of light through the atmosphere and summarizes the available theory and experiments that may be used to analyze image distortion and compensate for it. The most important methods that are used to compensate for image distortion caused by atmospheric turbulence are also discussed. The chapter emphasizes the assumptions that are used in the underlying propagation theory and the compensation methods. The importance of optical intensity fluctuations in addition to phase fluctuations and the far-reaching effects of the assumption of isoplanicity in compensation techniques are also discussed in the chapter.