12-09-2014, 12:23 PM
Night Vision Techniques and Their Applications
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Abstract:
This paper describes the various Night vision techniques."Night Vision" is referenced as technology that provides
us with the miracle of vision in total darkness and the improvement of vision in low light environments. This technology is an
amalgam of several different methods each having its own advantages and disadvantages. The most common methods
described here are Low-Light Imaging, Thermal Imaging and Illumination’s. This paper also give brief idea about various
night vision device (NVD) that allows images to be produced in levels of light approaching total darkness,it also explains
various applications where night vision technology is used to solve various problems due to low light conditions .
. INTRODUCTION
Night vision signifies the ability to see in dark (night). This capability is normally possessed by owls and cats, but
with the development of science and technology devices has been develop which enables human being to see in dark as well
an in adverse atmospheric conditions such as fog ,rain, dust etc.The muscles in the human eye have the ability to stretch or
contract automatically, depending upon the intensity of light falling on the eye. When we go out in bright sunlight, the pupil
gets contracted. Alternatively, when we enter a shaded or dark room at that time the muscles of eye relax and make the
aperture of the eye lens big enough to allow sufficient amount of light to pass through,therefore the objects in the room
appear blurred. Because of this human eye have limitations. The muscles of eye cannot increase the aperture indefinitely.
Therefore, in poor light we are unable to see the objects because the image cannot be formed on the retina clearly. The
capability to detect and identify targets at night and under poor visibility conditions has been an essential military
requirement. The modern army's need to operate at night and under conditions of extremely poor visibility , Since the
soldiers have to often fight in the dark at night, they have to face a severe stress as far as the location of target is concerned.
Also various wild life observer have to to face problems of low light because many wild animals are more active during
night time than day ,therefore to observe there lifestyle and study it night vision is important . Therefore to make human
being unable to see in dark by technological means, night vision technology has been developed. This paper describes
various techniques and different devices developed to enable viewing in dark.
Active Illumination
Active illumination technologies work on the principle of coupling imaging intensification with an active source of
illumination in the near infrared (NIR) band. Infrared is used in night vision technology when there is insufficient visible
light to see, active illumination involves conversion of ambient light photons into electrons which are then amplified by a
chemical and electrical process and then converted back into visible light. Active infrared night vision combines infrared
illumination in spectral range 0.7–1 μm. Due to which The scene, which appears dark to a human observer now appears as a
monochrome image on a normal display device. Since active infrared night vision systems can incorporate illuminators that
produce high levels of infrared light, the resulting images are typically higher resolution than other night vision
technologies.
The use of infrared light and night vision devices should not be confused with thermal imaging which creates images based
on differences in surface temperature by detecting infrared radiation (heat) that emanates from objects and their surrounding
environment
Working Of Thermal Imaging
A special lens focuses the infrared light emitted by all of the objects in view. The focused light is scanned by a phased array
of infrared-detector elements. The detector elements create a very detailed temperature pattern called a thermogram. It only
takes about one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram.
This information is obtained from several thousand points in the field of view of the detector array. The thermo gram created
by the detector elements are translated into electric impulses.
The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from
the elements into data for the display. The signal-processing unit sends the information to the display, where it appears as
various colors depending on the intensity of the infrared emission. The combination of all the impulses from all of the
elements creates the image.
Security
There are lots of challenges in performing video surveillance at night. The optimal solution for a particular
application will depend on the requirements for the specific application. For example, is daytime operation required? Does
the system need to be covert what is the size and shape of the area to be monitored? Is the goal of the surveillance to detect,
recognize or identify subjects in the field of view? The night vision camera provide best surveillance during night or low
light condition and thus prevents the chances of theft, terriost attack etc
CONCLUSION
In this paper we have described various night vision technologies which are available and also its working in order
to avoid various low light problem, this paper shows that how efficiently a soldiers can work efficiently during night also
wild life observer can work during dark and also shown how surveillance can be kept in low light condition .this paper
summarize a various generations of night vision technology
[attachment=67869]
Abstract:
This paper describes the various Night vision techniques."Night Vision" is referenced as technology that provides
us with the miracle of vision in total darkness and the improvement of vision in low light environments. This technology is an
amalgam of several different methods each having its own advantages and disadvantages. The most common methods
described here are Low-Light Imaging, Thermal Imaging and Illumination’s. This paper also give brief idea about various
night vision device (NVD) that allows images to be produced in levels of light approaching total darkness,it also explains
various applications where night vision technology is used to solve various problems due to low light conditions .
. INTRODUCTION
Night vision signifies the ability to see in dark (night). This capability is normally possessed by owls and cats, but
with the development of science and technology devices has been develop which enables human being to see in dark as well
an in adverse atmospheric conditions such as fog ,rain, dust etc.The muscles in the human eye have the ability to stretch or
contract automatically, depending upon the intensity of light falling on the eye. When we go out in bright sunlight, the pupil
gets contracted. Alternatively, when we enter a shaded or dark room at that time the muscles of eye relax and make the
aperture of the eye lens big enough to allow sufficient amount of light to pass through,therefore the objects in the room
appear blurred. Because of this human eye have limitations. The muscles of eye cannot increase the aperture indefinitely.
Therefore, in poor light we are unable to see the objects because the image cannot be formed on the retina clearly. The
capability to detect and identify targets at night and under poor visibility conditions has been an essential military
requirement. The modern army's need to operate at night and under conditions of extremely poor visibility , Since the
soldiers have to often fight in the dark at night, they have to face a severe stress as far as the location of target is concerned.
Also various wild life observer have to to face problems of low light because many wild animals are more active during
night time than day ,therefore to observe there lifestyle and study it night vision is important . Therefore to make human
being unable to see in dark by technological means, night vision technology has been developed. This paper describes
various techniques and different devices developed to enable viewing in dark.
Active Illumination
Active illumination technologies work on the principle of coupling imaging intensification with an active source of
illumination in the near infrared (NIR) band. Infrared is used in night vision technology when there is insufficient visible
light to see, active illumination involves conversion of ambient light photons into electrons which are then amplified by a
chemical and electrical process and then converted back into visible light. Active infrared night vision combines infrared
illumination in spectral range 0.7–1 μm. Due to which The scene, which appears dark to a human observer now appears as a
monochrome image on a normal display device. Since active infrared night vision systems can incorporate illuminators that
produce high levels of infrared light, the resulting images are typically higher resolution than other night vision
technologies.
The use of infrared light and night vision devices should not be confused with thermal imaging which creates images based
on differences in surface temperature by detecting infrared radiation (heat) that emanates from objects and their surrounding
environment
Working Of Thermal Imaging
A special lens focuses the infrared light emitted by all of the objects in view. The focused light is scanned by a phased array
of infrared-detector elements. The detector elements create a very detailed temperature pattern called a thermogram. It only
takes about one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram.
This information is obtained from several thousand points in the field of view of the detector array. The thermo gram created
by the detector elements are translated into electric impulses.
The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from
the elements into data for the display. The signal-processing unit sends the information to the display, where it appears as
various colors depending on the intensity of the infrared emission. The combination of all the impulses from all of the
elements creates the image.
Security
There are lots of challenges in performing video surveillance at night. The optimal solution for a particular
application will depend on the requirements for the specific application. For example, is daytime operation required? Does
the system need to be covert what is the size and shape of the area to be monitored? Is the goal of the surveillance to detect,
recognize or identify subjects in the field of view? The night vision camera provide best surveillance during night or low
light condition and thus prevents the chances of theft, terriost attack etc
CONCLUSION
In this paper we have described various night vision technologies which are available and also its working in order
to avoid various low light problem, this paper shows that how efficiently a soldiers can work efficiently during night also
wild life observer can work during dark and also shown how surveillance can be kept in low light condition .this paper
summarize a various generations of night vision technology