X Международная студенческая научная конференция Студенческий научный форум - 2018

The Night Vision Device (NVD) is a class of optoelectronic devices that provide the operator with an image of the terrain (object, purpose, etc.) in conditions of insufficient illumination. Instruments of this type are widely used in night combat operations, for conducting secret surveillance (surveillance) in the dark and in dark rooms, driving cars without the use of unmasking lights, etc. Despite the number of advantages that they give to their owner, it is noted that the vast majority of available models are not able to provide the opportunity for peripheral vision, which necessitates special training for their effective application.

There are several approaches to the construction of a PNV:

Amplification of very weak visible light, not distinguishable by the eye of a person. The idea is realized in electron-optical converters (EOP) and, to some extent, in modern video cameras for security systems with so-called. night mode.

Observation in the near infrared range (wavelength 0.7 .1.5 microns). Sensitivity in this range is the image intensifier and video cameras without an infrared filter. In the near IR there are no natural sources except the sun, so in total darkness such NVOs will see nothing without illumination. For such NVN there are special sources of illumination (infrared projectors, for example, based on infrared LEDs), invisible to the naked eye. Observation in the middle (thermal) infrared range (wavelength 7..15 μm). In this range, all solid bodies radiate to the temperatures of our world: from -50 degrees Celsius and above. Such NVOs are called thermal imagers. They show a picture of the temperature difference, and do not require any backlighting.

It is possible to observe in the ultraviolet spectrum. However, the lack of natural sources of ultraviolet (except the sun) and the practical absence of artificial sources of ultraviolet illumination invisible to the naked eye hampers the spread of ultraviolet NNV.

Technically, there are several popular ways to build a PNV:

Special modern semiconductor video cameras are able to give an image with the illumination of the scene up to 0.0005 lux. [3] This allows you to observe at very low illumination. In addition, sensitivity in the near infrared range allows you to organize invisible illumination of the scene (for example, infrared LEDs) and use conventional video cameras without an IR filter. To avoid color errors, conventional home video cameras are equipped with a special filter that cuts the IR spectrum. Cameras for security systems or cheap home video equipment do not have such a filter and are therefore suitable for surveillance with IR illumination. However, in the dark there are no natural sources of near IR, so without backlighting, such cameras will not show anything. As a backlight, infrared LED spotlights are usually used.

The electron-optical converter is a vacuum photoelectric device that enhances the light of the visible spectrum and the near-IR. Has a high sensitivity and is able to give an image at very low illumination. They are historically the first devices of night vision, are widely used and now in cheap NVV. Since the infrared range is sensitive only in the near-IR, then, like semiconductor video cameras, require the presence of lighting (for example, the night sky light or infrared illuminators). The coefficient of amplification of the light is from several thousand to several tens of thousands of times.

A thermal imager is a thermal video sensor, usually based on bolometers. Bolometers for vision systems and night vision devices are sensitive in the wavelength range 3..14 μm (medium infrared range), which corresponds to the radiation of bodies heated from -50 to 500 degrees Celsius. Thus, bolometric instruments do not require external illumination, registering the radiation of the objects themselves and creating a picture of the temperature difference.

Modern NVV are produced in several basic form factors. The simplest is the night monocular - the telescope, which is kept in the operator's hand, is usually of low multiplicity. Night vision binoculars have two image intensifiers and display an enhanced stereoscopic image. Night vision goggles - fixed on the head, have a wide field of view and do not enlarge the image (or have a variable increase from 1x to a higher value, which allows using them as binoculars). Glasses can have two tubes or be pseudo-non-circular when the image from one tube arrives at both eyepieces. Monocular multiplicity 1x, attached to the headband, can be used as a cheap alternative to points. The night vision sights are fixed on the arms, usually increase the image and have an aiming grid. There are also night vision attachments to daytime optical sights. These devices must withstand the recoil of weapons, not all sights can be used on high-powered firearms. An alternative option for aiming through the NVN is to use an infrared laser target designator attached to the weapon, an invisible ray of which is observed through the night vision goggles. Night Vision devices are also installed on military equipment, where they are integrated into sighting systems.

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