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Night Vision in Analog Cameras

August 8, 2022

How Infrared Night Vision Security Cameras Work

An infrared night vision camera works by beaming infrared light onto its field of view and then seeing that field of view with specialized infrared light sensors. Because human beings are incapable of perceiving infrared light, an infrared camera can easily see areas that are pitch-black to the naked eye.

About the light spectrum

The human eye is able to see light and its various colors by perceiving and interpreting wavelengths in the "visible light" range of the electromagnetic spectrum. The highest frequency electromagnetic waves are small and compact while the lowest frequency waves are relatively wide. "Visible light" is a small range of frequencies toward the center of the much larger electromagnetic spectrum.

Night vision security cameras, as well as antenna-based communications like radio, are possible because the electromagnetic spectrum's true range of frequencies and wavelengths is much wider than the narrow band that can be perceived by the human eye.

The smallest electromagnetic wavelengths that are visible to human beings appear violet and the largest wavelengths appear red. The rest of the colors we can see have wavelengths that are somewhere in size between those of violet and red. Yellow, which is close to the center of the visible range, has wavelengths that are about midway in size between those of violet and red.

Night Vision Technology: How Analog Infrared Cameras See In Complete Darkness

Infrared cameras come with build-in LED lights for night vision capabilities. Infrared LED lights are usually in the camera itself, and sometimes they even surround the camera lens.

These LED lights turn on during total darkness to shine IR light onto the security camera's field of view. The security camera is then able to capture footage by seeing the infrared light waves reflect off objects and then translating the infrared into wavelengths that are visible to the naked eye.

While the field of view of an infrared security camera may appear pitch-dark to an unaided eye, it is in reality not dark at all. It is simply lighted by infrared electromagnetic waves that are too wide for human perception.

How Analog Infrared Night Vision Works

An analog camera is able to produce superior night vision by relying on a specialized image intensifier tube. Upon beaming vibrating infrared electrons on the camera's field of view, the infrared reflects back into the camera's IR sensor, where it reaches a charged photocathode plate. The plate shoots the vibrating infrared electrons through a vacuum tube to hit a microchannel plate, which lets the night vision image screen represent the same pattern of infrared light that struck the photocathode in a frequency that people can see.

Depending on whether an analog camera's image intensifier tube uses green or white phosphorus, the resulting image will have either a green hue or be in black and white. When you see a green hue in night vision, you know that an analog camera is being used.

Most analog infrared cameras require an IR cut filter to avoid IR night vision mode in bright situations. When light sensors inside these cameras perceive bright visible light, they activate the IR cut filter, which functions as a mechanical shutter to block IR light from beaming onto the camera's field of view. Without these IR filters, there would be excessive feedback in bright-light situations that would result in distorted images and possibly even cause damage to the camera.

How Analog Color Night Vision Cameras See Color in Low-Light Settings

There are two major types of analog night vision: Infrared vision and colored night vision.

Many indoor and outdoor night vision devices are able to capture color images in low-light environments because of specialized image sensor technology that is extremely sensitive to and absorbent of light.

While color night vision images are pretty cool, a camera using infrared can generally achieve higher resolution images than a color night vision camera--even in conditions with ambient light. Infrared LEDs also provide a much greater range than their color night vision counterparts. Many IR cameras have a night vision range as far as one-hundred-thirty feet in total darkness while the colored night vision range tends to be limited to forty feet.

Analog vs. Digital Night Vision Security Cameras

Most digital security cameras can easily increase or decrease their sensitivity to light and do so automatically depending on the environment. Like analog IR cameras, most digital cameras also are able to capture infrared night vision with LED light technology, as well as capture color footage in low-light environments.

Nevertheless, digital security cameras have inferior night vision clarity and resolution when compared to analog security cameras because they depend on digital enhancement technology rather than image intensifier tubes for optical viewing.

Which analog camera offers the best night vision?

The best Night Vision cameras that are well priced and appropriate for home security are Nest Indoor cameras by Google. These infrared cameras provide high-definition video quality and, because there's no visible red glow when they're in IR night vision mode, they provide more discretion than most security cameras with night vision capabilities. The most exciting features of a Nest Cam are connected to their artificial intelligence capabilities, which include motion detection, person detection, and facial recognition.

While a Nest Cam has a lot to offer, it's important to be aware of the product's drawbacks before investing in one. A nest cam must be plugged in with a power cable, which can be distasteful to some customers, and there is no local storage for security footage. The relatively cheap price of a Nest cam starts to increase as one looks at the small print. If you don't want your surveillance footage to be erased after a mere three hours, you have to pay Google a monthly subscription fee for cloud storage. And as cool as the camera's AI features are, they also mostly require monthly subscription fees.

The Electromagnetic Spectrum and Night Vision Cameras

Infrared light is electromagnetic radiation in wavelengths that are wider than those of visible light. Analog IR night vision cameras can see in total darkness by beaming LED light in the infrared range on their field of view and then translating the resulting images to wavelengths that human eyes can see.

Infrared night vision analog cameras tend to produce footage in black and white or in a green image hue, but they capture higher resolution images than digital cameras and they can function without any light from the visible spectrum. Unless color night vision is important to you, IR cameras are your best night vision option for clear, high-definition surveillance in absolute darkness and low-light setting.





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