Night vision in security camera:
- Types of Night Vision
- Working of Technical Night Vision
- Night Vision Devices
- Night vision technology, literally allows one to see in the dark.
- It is originally developed for military use .
- Humans have poor night vision compared to many other animals.
- With the proper night-vision equipment, we can see a person standing over 200 yards (183 m) away on a moonless, cloudy night.
TYPES OF NIGHT VISION:
It is broadly classified into two types
- Biological Night Vision
- Molecules in the rods of the eye undergo a change in shape as light.
- Molecules in the human rods is insensitive to the light.
- Technical Night Vision
- Image intensifier
- Thermal imaging
WORKING OF TECHNICAL NIGHT VISION:
Technical Night vision can work in two very different ways
- Image Intensifier
- Night vision amplifies light to achieve better vision .
- A conventional lens, captures ambient light.
- The gathered light is sent to the image-intensifier tube.
- The light energy released electron from the cathode and
- These electrons enter micro channel plate and bounce off and generate more electron.
- Thousands of other electrons to be released in each channel.
- Original electrons collide with the channel,exciting atoms and causing other electrons.
- New electrons collide with other atoms, creating a chain.
- In image-intensifier tube, the electrons hit a screen.
- The energy of the electrons release photons and create green image on the screen.
- The green phosphor image is viewed through another lens.
All objects emit infrared energy as a function of their temperature.
- A lens focuses the infrared light.
- The focused light is scanned and create temperature pattern.
- The pattern created is translated into electric impulses.
- The impulses are sent to a circuit board that translates the information into data for the display.
- The signal-processing unit sends the information to the is play, and appears as various colors.
- Thermal images are black and white in nature.
Night vision devices are basically divided into three categories
- They are monocular normal handheld or mounted on a weapon
- They are binocular and worn on the head.
- Used for transmission or recording of images mostly if the location is fixed
The earliest (1950’s) night vision products were based on image conversion, rather than intensification
- Vacuum Tube Technology
- Full Moon Operation
- Amplification: 1,000
- Operating Life: 2,000 Hours
- First Micro channel Plate Application
- One-Quarter Moon Operation
- Amplification: 20,000
- Operating Life: 2,500 Hours
- Improved Micro channel Plate & Photocathode
- Starlight Operation
- Amplification: 40,000
- Operating Life: 10,000 Hour
- Wildlife observation
- Hidden-object detection
- No particular skill required
- Accidents cases reduction
- Compact system
- 3x range visual
- The only disadvantage is that the Initial cost too high.