Diffraction of Waves by a Planar Junction of Impedance and Perfect Electromagnetic Conductor Half-Planes

In this study, diffraction of waves by a planar junction between impedance and perfect electromagnetic conductor half-planes is investigated. The method of transition boundary is used for the solution of the problem. The diffracted wave expressions are expressed in terms of the Fresnel functions by using the uniform theory of diffraction method. Thus, finite magnitudes are obtained at the transition regions and the results are analyzed numerically for different set of parameters.

Contrast of Image of an Object Observed in Smoke Conditions using Polarizing Filtering of Radiation Scattered by Smoke Particles

The aim of the work was to study the contrasts of the images of an object observed in a smoky environment, using polarizing filtering of radiation scattered by smoke particles towards the observer, and without filtering. Prospects for developing optical accessories for firefighters to improve the observation of objects in smoke were evaluated by comparing image contrasts.The goal was achieved by experimentally simulating the process of transmitting images of a blackandwhite object with a sharp black/white transition boundary through various types of smoke aerosols using polarizing filtering of radiation scattered by smoke particles, and without filtering and evaluating image contrasts.Studies of image contrasts for different optical densities of smoke in two registration schemes were performed, when the receiving optical system is located near the illumination source of the object at a distance of ≈ 150 mm from it, and when it is located at a distance from the illumination source of the object at a distance of ≈ 800 mm.It is established that the method of forming the image of the object using polarization filtering of radiation backscattering (RBS) reduces the rate of image contrast reduction with an increase in optical smoke density compared to image registration without filtering (RBS).A significant difference in the contrasts of images recorded with filtration (RBS) and in the absence of it is observed for "light" fumes (smoldering of wood, cotton) at average optical densities of smoke.The results obtained can be used in the development of optical accessories for firefighter-rescuer to improve the conditions of observation of objects in adverse conditions of vision: smoke, vaporization, fog.