To achieve safer navigation without sudden collisions with large cetaceans at high speed boats such as the hydrofoil, we examined its feasibility of an installation of the infrared camera. Because any ceta-ceans are of air-breathing animals, it is theoretically expected that they can be potentially detected through imaging of the infrared cameras. Thus, we examined the feasibility of detection with aiming at sperm whales in waters off Chichijima Islands (27°4'N, 142°13'E), Japan. Through the experiment, it was revealed that sperm whales could be detected stably within 200m, and detectable cue were blow, back body and fluke tails. However, boats and waves were also detected as noise images. Especially, waves greatly resemble the whale back bodies. Although potential of the infrared camera was confirmed, there are still necessities of further ex-periments including ones conducting at different temperate waters, to successfully install the infrared camera for earlier finding of large cetaceans.
The paper presents modern sensor systems for sniper detection. Among such systems there are active and passive optoelectronic devices. Its primary advantage is the possibility of early recognition of the threat, before the sniper is able to take the shot. Presented passive systems employ thermal cameras and advanced image processing algorithms to distinguish the sniper and muzzle blast signatures. Active systems, in turn, rely on the detection of laser radiation, retro reflected from pointed optics (optical sights and observation scopes). The paper presents basic technical and tactical characteristics of sniper detection devices, both standalone and included in multi-sensor detection systems.
PL
W artykule przedstawiono współczesne systemy detekcyjne przeznaczone do wykrywania snajpera. Wśród systemów tego typu, wprowadzanych na uzbrojenie wielu armii istotną rolę pełnią pasywne i aktywne systemy optoelektroniczne. Ich zaletą jest możliwość wczesnej detekcji zagrożenia, zwłaszcza przed oddaniem strzału przez snajpera. Przedstawione systemy pasywne wykorzystują kamery termowizyjne i zaawansowane metody analizy obrazu w celu wykrycia sygnatur snajpera i strzału z broni palnej. Systemy aktywne wykorzystują z kolei promieniowanie laserowe w celu wykrycia optycznych przyrządów celowniczych i obserwacyjnych.
This study analyses the impact of varying temperature and salinity stratifications on the thermal characteristics of the wake through a newly established simulation model, the reliability of which is confirmed by experimental validation. In a stratified environment with sTable positive salinity but a temperature changing from positive to negative, the wake has “cold” and “hot” characteristics at the free liquid surface, respectively, and these characteristics are enhanced with an increase in the temperature gradient. In a stratified environment with a sTable positive temperature but changing positive salinity, the wake stream has “cold” characteristics at the free liquid surface, and the feature intensity has a weak positive correlation with the salinity gradient. In general, under the boundary and initial conditions studied in this paper, temperature stratification is the main factor determining the thermal characteristics of the free surface, and salinity stratification is the secondary factor. The influence of the moving induced wake on the thermal characteristics of the wake is stronger than that of the buoyant jet. In a follow-up study, we will focus on a scale analysis of the impact of stratified features on the wake, and scale extrapolation. The influence of the free surface thermal boundary layer on the wake characteristics will be another key point for investigation.
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