Teodor Baláž

Simulation of Laser Attacks against Aircrafts

Threats of laser attacks against transport planes are increasing around the world in the last time. Common laserpointers are used for suchattacks, which emit a continuous greenlaserbeam with the wavelength of λ = 532 nm, and the power emitted is hundreds of milliwatts. This situation is dealing with laws in many countries. The goal of the paper is to contribute to a solution to these dangerous situations for air traffic. The spatial analysis is possible to create in which the configuration of the landscape surrounding the airport, the position of the landing airplane, and parameters of irradiation are considered. The results identify locations from where suchattacks are possible. Such results can aid police by increasing their efficiency in intervening against laser attackers.

Evaluation of validity of observer test for testing of camouflage patterns

Physical characteristics of camouflage patterns such as color or remission spectra can be tested and measured by objective methods. In the vast majority of use of camouflage pattern, the human (obscure person) will recognize the camouflaged object. Therefore, the quality of the camouflage pattern ultimately determines how a person in a given environment perceives the camouflage pattern. Human perception is very subjective, and its assessment cannot be measured by simple physical methods. Therefore, we process the observer’s visual performance when searching for camouflaged objects. It must always be based on the statistical processing of information on perceived quality of camouflage by individual observers. One of the methods for assessing the quality of camouflage surfaces is so called observer test. The observer test is a simple visual test in which a number of viewers observe a series of images of different scenes containing camouflaged object. The time taken to find the camouflaged object is measured. Depending on the time, it takes to find the camouflaged object, the quality of the camouflage pattern is judged. The time required to find a camouflaged object depends, among other, on the arrangement of the scene, the conditions of the observer test, how the observer interacts with the test interface, the observers properties and last but not least the camouflage pattern quality. The time taken to find a camouflaged object by a particular observer in a particular frame must be assumed as a random variable because it depends on a large number of independent factors. The rated quality of the camouflage pattern is only one of these factors. Among the others, it was aim of the experiment we performed to evaluate the statistical behavior of the random variable to be able to describe the behavior of it by a suitable type of distribution.

Selected issues connected with determination of requirements of spectral properties of camouflage patterns

Traditionally spectral reflectance of the material is measured and compared with permitted spectral reflectance boundaries. The boundaries are limited by upper and lower curve of spectral reflectance. The boundaries for unique color has to fulfil the operational requirements as a versatility of utilization through the all year seasons, day and weather condition on one hand and chromatic and spectral matching with background as well as the manufacturability on the other hand. The interval between the boundaries suffers with ambivalent feature. Camouflage pattern producer would be happy to see it much wider, but blending effect into its particular background could be better with narrower tolerance limits. From the point of view of long time user of camouflage pattern battledress, there seems to be another ambivalent feature. Width of the tolerance zone reflecting natural dispersion of spectral reflectance values allows the significant distortions of shape of the spectral curve inside the given boundaries.

Tracking, aiming, and hitting the UAV with ordinary assault rifle

The usage small-unmanned aerial vehicles (UAVs) is significantly increasing nowadays. They are being used as a carrier of military spy and reconnaissance devices (taking photos, live video streaming and so on), or as a carrier of potentially dangerous cargo (intended for destruction and killing). Both ways of utilizing the UAV cause the necessity to disable it. From the military point of view, to disable the UAV means to bring it down by a weapon of an ordinary soldier that is the assault rifle. This task can be challenging for the soldier because he needs visually detect and identify the target, track the target visually and aim on the target. The final success of the soldier’s mission depends not only on the said visual tasks, but also on the properties of the weapon and ammunition. The paper deals with possible methods of prediction of probability of hitting the UAV targets.

Pixelated camouflage patterns from the perspective of hyperspectral imaging

Pixelated camouflage patterns fulfill the role of both principles the matching and the disrupting that are exploited for blending the target into the background. It means that pixelated pattern should respect natural background in spectral and spatial characteristics embodied in micro and macro patterns. The HS imaging plays the similar, however the reverse role in the field of reconnaissance systems. The HS camera fundamentally records and extracts both the spectral and spatial information belonging to the recorded scenery. Therefore, the article deals with problems of hyperspectral (HS) imaging and subsequent processing of HS images of pixelated camouflage patterns which are among others characterized by their specific spatial frequency heterogeneity.

Utilization of hyperspectral camera for determination of camouflage surfaces spectral characteristics homogeneity

The paper deals with description of newly developing method of Hyperspectral camera utilization for determination of camouflage surfaces spectral characteristics homogeneity. The color patterns of camouflage surfaces are usually checked pointwise. It is assumed subsequently that the spectral characteristics of the pattern are the same for whole area of camouflage surface. The essential properties of hyperspectral camera allow to determine the level of spectral qualities homogeneity of the surface. Although the respective snapping of hyperspectral image is fairly easy, the evaluation of HS datacube features specific problems connected with homogeneity of illuminance, optical system aberrations, transformation to reflectance and spectral unmixing. All the measurement aspects have to be taken into account to correctly determine the homogeneity of camouflage surfaces spectral characteristics.