We present a road extraction system from aerial imagery guided by an imprecise road network. After a general discussion on road extraction strategies, we focus on the road recognition module we propose. It relies on two principal elements : a general purpose parallel structures detector in images, which uses a simulation of light ray propagation and reflections; and a dynamic programming based ...

The magic garment worn by the fictional wizard Harry Potter makes him invisible and simultaneously allows him to see the outside world. The concept of this type of invisibility cloak has captured the imagination for centuries and has inspired many recent explorations in the field of optics. Making such a fictional garment is indeed a grand challenge: when invisible to the outside observer, the ...

We present the first detailed account of modelling pulses in Helmholtz-type nonlinear systems with both temporal and spatial dispersion. Exact analytical solitons will be reported, and their stability examined through mathematical analysis and computer simulations. © 2010 Optical Society of America OCIS codes: (190.5530) Pulse propagation and temporal solitons; (190.4400) Nonlinear optics, mate...

The numerical dispersion relation that governs the propagation of fields in a finite-difference time-domain (FDTD) grid was derived several years ago. In this paper a different interpretation is given for the governing equation. It is shown that the dispersion relation predicts fasterthan-light propagation for coarsely resolved fields. Additionally, some spectral components that were previously...

Dynamic media such as atmospheric clouds and fog form a formidable barrier to light propagation for free-space optical communication (FSO). To overcome an obstacle, we propose make use of the acoustic properties laser filament coupled together with donut-shaped signal beam. A generated by ultrafast is accompanied wave that clears cylindrical chamber around filament’s plasma column can mimic tra...

Using two different approaches, we study imaging in the strong-lensing regime taking into account effects of plasmatic environments on light propagation. First, extend use a perturbative approach that allows us to quickly and analytically calculate position shape images circular source lensed by galaxy. Such an will be compared with obtained from numerical solution lens equations. Secondly, int...

This thesis incorporates the concept of light propagation in non-Hermitian media. We use the waveguide arrays and one dimensional photonic crystals as the frameworks for our investigations. The notion of non-Hermiticity is implemented into these structures by considering the fact that the electromagnetic parameters of an optical medium can contain imaginary components. These imaginary component...

Realistic rendering of participating media like clouds requires multiple anisotropic light scattering. This paper presents a propagation approximation for light scattered into M direction bins, which reduces the \ray eeect" problem in the traditional \discrete ordinates" method. For a regular grid volume of n 3

It says in the report by Wang et al. that a negative group velocity u = −c/310 is obtained and that a pulse advancement shift 62-ns is measured. The authors claim that the negative group velocity is associated with superluminal light propagation and that the pulse advancement is not at odds with causality or special relativity. However, it is shown here that their conclusions above are not true...