Turbulence in the earth’s atmosphere severely limits the resolution and sensitivity of astronomical observations. The vertical distribution of turbulence in the atmosphere has a profound effect on the residuals after correction by an active instrument such as adaptive optics or a fringe tracking interferometer. It has already been shown that the South Pole has turbulence profiles unlike those a...

Deconvolution of images taken through atmospheric turbulence often requires regularization in order to prevent the restoration algorithm over-fitting the noisy observation. For this purpose many object priors have been proposed but their utility might be limited to one class of real objects. Optical effects of atmospheric turbulence are well understood and therefore priors on the point-spread f...

This work aims to quantify and improve the sensitivity of monocular passive ranging techniques in sequences that are degraded by the the quasi-periodic inter frame motion and localised blurring associated with atmospheric scintillation. Ranges from tens of meters up to 1km in uncontrolled outdoor conditions were investigated. This work has application in surveillance, border control, artillery,...

We analyze the influence of atmospheric turbulence on the propagation of an optical vortex beam having the form V(r,theta)=A(0)e(imtheta). The probability that a detected photon after propagating through the atmosphere has the same value of the orbital angular momentum as the launched photon is found to be given by s(0)=[1+(1.845D/r(0))(2)](-1/2), where D is the aperture diameter and r(0) is th...

Free-Space Optical (FSO) communication is reputed for its ability to proffer solution to the access network bottle-neck but when used over long range communication links, it suffers from scintillation caused by the atmospheric turbulence. The scintillation is modelled using the negative exponential distribution. Hereby, we present the outage probability and the bit error probability equations o...

Free-space optical communication has the potential to transmit information with both high speed and security. However, since it is unguided it suffers from losses due to atmospheric turbulence and diffraction. To overcome the diffraction limits the long-distance propagation of Bessel beams is considered and compared against Gaussian beam properties. Bessel beams are shown to have a number of be...

In this paper, the performance of decode-and-forward relay-assisted free-space-optical (FSO) communication systems under atmospheric turbulence induced fading and misalignment errors is investigated. To mitigate the adverse effects of the atmospheric turbulence, the aperture averaging receivers are considered both at the relay and destination sides. The atmospheric turbulence induced fading is ...

In this work, the possible chaotic nature of the atmospheric turbulence above a densely forested area in the Amazon region is investigated. To this end, we use high-resolution temperature data obtained during a micrometeorological measurement campaign in the Brazilian Amazonia. Estimates of the correlation dimension (D(2)=3.50+/-0.05) and of the largest Lyapunov exponent (lambda(1)=0.050+/-0.00...

This article analyzes and discusses a well-known paper [D. Li, R.M. Mersereau and S. Simske, IEEE Letters on Geoscience and Remote Sensing, 3:4 (2007), pp. 340–344] that applies principal component analysis in order to restore image sequences degraded by atmospheric turbulence. We propose a variant of this method and its ANSI C implementation. The proposed variant applies to image sequences acq...

This book has been awaited in the atmospheric boundary-layer research community for a long time. JohnWyngaard, the author of the book, is by all counts an outstanding figure in the area of atmospheric turbulence studies. His contributions to the field are both numerous and exceptional. As a person, John comprises all the principal qualities of an outstanding scientist and academic: curiosity, w...