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How do night vision cameras work

How do night vision cameras work

Looking to do a little ghost hunting? In the mood to re-enact your favorite scene from “Predator”? Whatever your pleasure — from security to nature-watching to artistic expression — there’s a night-vision camera for you.

Nighttime photographers entered the picture in 1871, when Richard L. Maddox developed a photographic plate that was finally up to the task. Early photographers captured images on wet plates — panes of glass coated with chemicals — which were touchy and cumbersome and required exposure times that made night photography impractical. Maddox’s gelatin dry plate changed all that, becoming the first medium capable of capturing nocturnal cityscapes [sources: Encyclopaedia Britannica; Schwendener].

As time passed and interest spread, legendary photographers such as Alfred Stieglitz, George Brassaï, Weegee and Diane Arbus brought better cameras, improved film and special development techniques to bear. These famed photogs peeled back the curtain of night not with night vision, but with the glow of city lights, illuminated signs, moonlight and the occasional flashbulb.

By the 1970s, Japanese photographers such as Kohei Yoshiyuki were stalking city parks at night, capturing voyeuristic tableaux with their infrared (IR) film and filtered flashbulbs. The era of true night-vision image capture had begun, and both criminals and young lovers would never be safe again [source: Schwendener].

From World War II to today, the U.S. armed forces have driven night-vision tech. As the military turns out incrementally better night-vision scopes, the technology finds its way into civilian cameras. Most prominently, closed-circuit security grew from its infancy in the 1970s to become commonplace by the 1990s [sources: Demetriadi; National Archives; Roberts].

Today, night vision is most widely available in security cameras. Some work only at night, while others switch modes based on user input or ambient light. Surveillance rigs can run from $18 for a 0.5-lux low-light camera to $3,670 for a top-of-the-line thermal imaging model (lux measures the minimum light a camera needs to pick up an image, so lower = better) [source: Brickhouse].

Out-of-the-box night-vision photography cameras are rare. The Midnight Shot NV-1, a dual-mode, digital color/IR camera offered through ThinkGeek for $99.99-$149.99, was the only exception we could find in 2012. In most cases, photographers turn instead to IR film, IR lights and special filters, or hack their digital cameras to capture IR (more on that later). Night-vision adapters for photographic and video cameras offer a simpler approach, but will set you back a cool $6,840-$10,819. Thermal imaging cameras, such as the FLIR T series, break the bank at $8,450-$14,294.

Whatever your shopping selection, your camera will use one of two basic approaches to see in the dark: It will either amplify dim visible light, such as the ambient nightglow of the moon and stars, or gather electromagnetic radiation types that humans can’t perceive, such as infrared.

It makes sense that we would end up taking these two approaches; after all, that’s how Mother Nature does it.

@craigelloyd
February 9, 2017, 6:40am EDT

How do night vision cameras work

Most security cameras come with night vision, which allow them to still see things even if it’s pitch black outside. But how does it work?

If you don’t know what we’re talking about, then you’ve probably at least seen night vision footage from those ghost-hunting TV shows—that black and white or black and green look is all too familiar. Many security cameras also include that same night vision technology, allowing them to capture footage even when it’s dark out.

Infrared Night Vision Bathes The Area in Light That’s Invisible to Our Eyes

There are a couple different types of night vision: One that most security cameras use, and one that night-vision goggles use. The most common type that’s used on most security cameras is infrared (IR) night vision, which relies on infrared light.

If you’ve ever looked at the front of a security camera, you’ve probably noticed that it’s covered in a handful of small LED bulbs. This is the IR light, and when it gets dark out, these lights turn on and act as a flood light of sorts, dousing the camera’s field of view with infrared light.

How do night vision cameras work

The thing is, infrared light is completely invisible to the naked eye. So it doesn’t look like a bright light is flooding the area from the outside, but it actually is—your eyes just can’t see it.

Furthermore, night vision footage from security cameras always looks black and white because human eyes can differentiate between black and white better than they can with other shades of colors, like red or blue. Because of that, most night vision cameras switch to a monochrome filter to make it easier for us to see the image.

How do night vision cameras workThere are many different types of light that we can see with our eyes, but infrared (IR) light is invisible to the naked eye.

Most security cameras that have night vision capabilities, including the Nest Cam, also have what’s called an IR cut filter. This automatically detects daylight and applies the filter to block out the IR light during the day in order to keep colors looking accurate. When nighttime arrives, the filter automatically gets removed, which lets more light in, including the IR light coming from the camera.

How do night vision cameras workPlacing a night vision camera near a window will result in the IR lights reflecting off the glass.

Intensifier Tubes Absorb Whatever Light They Can, and Amplify It

There’s also another type of night vision, and it’s more often found in night-vision goggles which contain something called “intensifier tubes.” In the most basic of terms, it involves using an extremely sensitive camera sensor that cranks up the intensity.

In more advanced terms, the available light that enters night-vision goggles (consisting of photons) gets turned into electrons, converting the light into an electronic signal of sorts. The electrons are then multiplied using a photomultiplier and then pass through a phosphor screen, which creates flashes of light that results in a brighter image.

All of the colors of light that enter the goggles are converted to a shade of green after they go through the phosphor screen, which provides that iconic look that you’re likely familiar with—human eyes are much more sensitive to green than most other colors.

Night vision goggles are possible because it’s never truly pitch black outside—it’s just very, very dark. In fact, it’s very difficult to block out all light unless you’re actively trying to do so. Night-vision goggles can take the little light coming from the moon or street lights and amplify it.

A regular camera can do something similar. Go into a dark room in your house (or go outside at night) and take a long-exposure picture using a camera (if it’s capable of taking long-exposure shots). The resulting image will be much brighter than what you actually see, since the camera is taking all the available light there is and amplifying it. If there was absolutely no light available, the camera wouldn’t be able to capture anything, no matter the exposure.

Again, though, this type of night vision is usually only found in night-vision goggles, and most security cameras that come with night vision capabilities rely on IR light, which is much cheaper to implement and gives you better image quality overall.

When it comes to your family’s safety and security, you don’t want to leave yourself vulnerable. Although most burglaries occur during the day, nighttime burglaries are almost just as common—so a top-notch security system should have you covered around the clock. And a camera is only effective if it can see the perpetrator and provide a clear record of the crime that occurred. That’s where a night vision security system comes in.

How does night vision work?

While traditional cameras use visible light to capture and record images, night vision cameras work by recording infrared radiation, which is a form of energy associated with heat. The warmer an object is, the more infrared radiation it gives off. This type of radiation is independent of light, so cameras that can detect it can record images even in complete darkness. Because humans naturally produce body heat and household objects do not, an intruder will show up clearly among the objects inside and outside your home.

Why night vision is important for home security

A large percentage of crimes occur at night when people are sleeping and criminals are harder to see. While traditional cameras offer a measure of security, they simply can’t protect you fully at night. Night vision offers the chance to detect criminals and activate other safety features of your system when you’re asleep and at your most vulnerable.

Night vision cameras, like those that are a part of a full home security system from Xfinity Home, work hand-in-hand with a smart system.

Xfinity Home also provides 24/7 Professional Monitoring services, so the authorities will be notified when an alarm is triggered. If you leave the house empty overnight or for an extended vacation, an outdoor night vision camera can detect activity when your neighbors can’t. So, you’ll know that help is on the way.

Xfinity Home offers indoor/outdoor cameras with night vision and other high-quality features. Build your security system so that it protects you day and night.

A total home security solution

Get peace of mind with 24/7 professional monitoring and so much more. Enhance your with smart security features, because smarter is safer.

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How do night vision cameras work

A night vision camera is a camera which has the recording capacity to record something even during nights. The working of a night vision camera is based on several methods that it brings in use to process pictures. This includes the usage of reflected light to produce images or to detect heat in an object to produce images.

These kinds of cameras are bought in use for wildlife photography, hunting, fishing, security purposes etc. Such cameras were highly expensive earlier, but the websites of online shopping like E-bay and Flipkart etc have made these cameras cheaper and handy. Let us discuss the working of these cameras in briefly today.

How do night vision cameras work

Night Vision Camera How it Works

1. Recall How We View anything:-

We view anything when light from that object enters our eyes. Same is the case with a night vision camera. These kinds of cameras use the reflected light which is not in a visible spectrum. Some of these cameras are destined to switch on the flash when sound or foot movement is detected while the others use the light spectrum invisible to human eyes.

2. These Cameras Operate In Night Mode:-

When the normal mode of your phone’s camera is not able to take pictures clearly, you switch it to night mode and the picture gets clearer. Somewhat same, but advanced technology is used in night vision cameras to give a clear and apt view of the surroundings. The cost and functioning power of such cameras is always based on the technology used and the quality of sensors equipped within the camera.

3. Detection of the Thermal Energy:-

Every living organism has a kind of thermal energy in himself. These cameras work on the same principle. They detect the heat energy emitting out of any object in order to detect its presence and then capture its image with the presence of that thermal energy only.

4. The Main Focus of Such Cameras:-

The main focus of such night vision cameras is to capture the available light better than any other camera. They are specialized in detecting any form of heat or light present around an object and as soon as they detect it, they capture an image which can be bought in use as a proof if you are spying on someone.

5. Quality of Sensor and Rays or Waves:-

The quality of the picture captured by any such camera depends highly on the quality of sensor positioned in it. The better the quality of sensor used, the better gets the quality of an image captured by it. Some of these cameras are also based on waves emitting approach and rays detection approach as well.

6. Usage of Infrared Rays for Object Detection:-

Some of these cameras also use Infrared Light rays in order to target the object and then the sensor which is attached with camera helps in processing the image. The spectrum of such rays is invisible to the human eyes and we see nothing while the camera proves successful in capturing such image with brilliance.

CCTV camera is an excellent way to protect your home and business from burglars. Wireless CCTV cameras allow you to monitor the activities around your premises from your smartphone. Nowadays, most surveillance cameras come with night vision which allows them to record footage even in the dark. Read on to know more about the working of night vision cameras.

What is a night vision camera?

A night vision camera is an optoelectronic device that captures images in low-lightning conditions. The image may be a combination of visible light and infrared light. These cameras are mostly used by law enforcement agencies but are also available for commercial use. They have an image intensifier tube and a water-resistant casing to protect the camera against rain. Some cameras also include optical devices, such as telescopic lens, sacrificial lens or mirrors.

How does night vision cameras work?

Night vision security cameras use one of these three methods to capture images in the dark.

Low-light imaging

Low-light imaging camera uses an image intensifier to amplify available light. The available light in the area is focused through the objective lens onto the photocathode of the image intensifier. The photocathode is a photosensitive material that emits electrons when light is focused on it. The electrons released by the cathode are accelerated by an electric field and they are bombarded on a plate. These electrons enter the holes of the plate and bounces on specially coated internal walls. This activity generates more electrons and creates a denser cloud of electrons representing an intensified version of the original image. This glows the phosphor screen and an image is generated on the screen of the attached device.

Thermal imaging

Thermal imaging cameras detect the objects by infrared radiation and creates an image based on that information. The emitted infrared light is focused by a special lens and it is scanned by a phased array of infrared-detector elements. The detector creates a detailed temperature pattern called a thermogram and it is converted into electric impulses. A signal-processing unit translates the impulses from the elements into data for display. The combination of these impulses creates an image on the screen.

Infrared illumination

Infrared illumination cameras detect the invisible wavelengths of light and use infrared light to illuminate images in dim lighting conditions. IR cameras have a series of infrared LEDs that transmit infrared light in the dark. As infrared light cameras can interfere with colour images, IR cameras have a cut-out filter to block it during the daytime. The filter is fitted between the lens and sensor, allowing only the visible light to pass through in the daytime. Once the light level in the area drops to a certain point, the cut-off filter changes its mode and allows infrared light to pass through it.

Some Useful Tips

The CCTV installation and the type of security camera can have a great impact on the quality of the recorded image. Here are some of the useful tips for getting the best from night vision cameras.

Make sure the IR is powerful

This is one of the most important things to consider while choosing a night vision camera. All IR cameras have a quoted maximum range of 5m to 50m. You must keep in mind that the image quality will not be the same as indicated in the quoted range. Estimate your camera range and then add on a third to it. So, if you want to see 30m, then it’s worth investing in a camera with a 40m range.

Ensure that the view is clear

It’s important to ensure there are no devices that block the vision of the camera. This is because most cameras will adjust the exposure to give the best image. If there is an object jutting the frame, the LEDs will concentrate their focus in that area. This makes the image darker or sometimes nothing can be seen on the screen.

Calculate the mounting height carefully

The height of the camera will play a very important role in determining the quality of the image. For instance, if your car is parked at 8m from the house and your camera is mounted 6m from the ground, the actual distance from the camera to the car is 10m. Keep in mind to consider this while mounting a security camera.

IR needs something to reflect off

The light from the IR camera will not be visible until is reflected back from some object. Sometimes, the camera will warn you when there is nothing in the area. This doesn’t mean that the IR is not working.

How do night vision cameras workHave you ever wondered how night vision works?

People usually ask this question whenever they see soldiers, secret agents or spies wearing night vision goggles and searching for something in the dark.

Even if you are not wearing the goggles, you can easily determine why people wear them. One obvious reason is to easily find someone hiding in the dark. You can also use them to patrol an are at night for any suspicious activity.

When it comes to night vision devices, there is a wide variance on the market, from military-grade technology, to toys.

Much of what you find online is meant for kids to wear and play with. These are cheaper night vision goggles that are really just spy gadgets for kids. You might consider picking up a pair as a Christmas or birthday present for a little one in your life, but not as a serious device for yourself.

We’ll cover where to find real night vision goggles, monoculars and binoculars below.

First let’s tackle our main questions: how does night vision work and what is the difference between the various generations?

How Night Vision Works: Two Ways

Hot objects give off infrared radiation, which is a kind of energy. This is what night vision devices are designed to detect.

Living beings give off heat. You can’t see it with the naked eye, but you can detect with one of these special devices.

Let’s get to the science part of it to find out exactly how you’re able to see in the darkness.

There are two different ways how night vision works.

The first is through enhancement of the image. This is possible through the collection of a small amount of light which includes the lower portion of the infrared (IR) spectrum.

The second is by means of thermal imaging. This is a technology that captures the infrared light spectrum’s upper portion. This is the spectrum produced as heat by living things and not a simple reflection of light waves, like visible light is.

All night vision devices basically function the same, whether they cost a hundred dollars or several thousand. The difference is in how well it functions.

If you are interested in getting a night vision device, it is important to consider how you’re going to use them.

Are they for an outdoor fun activity? You won’t need to spend too much.

Will you be using them to secure your property? You’ll want to spend a bit more.

Do you need one that you can use for professional surveillance? You’ll probably want to get a military-grade device.

Night Vision Generations: What’s The Difference?

As technology has improved, those improvements have been classified under different generations: 1, 2, 3, and 4.

Here are the details about each generation of night vision and also the kinds of devices that make use of the different generational technology.

Generation 1

The products that use this technology are the most affordable ones on the market. They allow you to see at night, but perhaps not that well in total darkness. This technology dates back to the 1960’s. Here are a few of the details:

  • Range of up to 75 yards
  • Low resolution images
  • Relies on built-in infrared illuminators which make the user easily visible (not good for cover operations)
  • Often results in “blooming,” which is image distortion when there’s excess light
  • Lack of versatility. For example, you can’t really add it to a rifle scope, or use it to capture video or still images.
  • Shorter life expectancy for these devices, as well as reduced battery life.

Generation 1 technology is good for kids or for just having fun. It may even be good enough for hunting (though you will lose the ability to stay hidden) and you can easily pick up something for under $100.

Generation 2

This next generation is a big step up from the first and it is actually a lot closer to the third than it is to the first. Here are some of the big improvements:

  • Up to 200 yard range
  • Good resolution and clean images that appear brighter
  • Can operate with IR illumination (good for covert night viewing)
  • Clear picture over entire field of view
  • Longer battery life, and life expectancy of the device.

Generation 2 devices are great for most uses and they generally cost a few hundred dollars.

Generation 3

This new technology is what the US military and special forces use. You can also purchase these kind of night vision devices for personal use, but they’re very expensive. Here are some of the features:

  • Up to 300 yards range
  • Excellent resolution and very bright images, with top-quality optics
  • Does well in very low-light conditions, as well as with excessive light
  • Very durable and with a long life expectancy.
  • Totally passive operation

Generation 3 technology is used by the military and private users who need night vision for professional application, like security and surveillance. Gen 3 devices cost several thousand dollars.

Generation 4

The last one, generation four, is a bit up for debate. According to the US Army, this designation doesn’t really exist. Upon testing, these devices that were initially classified as this didn’t meet the US Army standards and so this designation was removed.

These days, it’s more of a marketing ploy for companies who make products using this advanced-level tech. That said, it may be slightly better than gen 3 for some specific purposes.

However, not everyone are converts, so it’s kind of wait and see with this one.

What’s The Deal With White Phosphor Technology (WPT)?

WPT is now available in all version of night vision devices. The main difference is that the images are black and white, as opposed to the standard green and black.

The advantage to this technology is that the images are more natural and they can show better contrast in some cases. The military has mostly switched over, and we expect most consumer devices will soon follow suit.

What Night Vision Devices Are Worth Getting?

With all the terrible products and all the toys on the market, it can be difficult to find quality night vision devices that are able to perform the tasks you need them to perform. We’ve done the research and have found the best ones at various price levels. Check out the following articles:

For fun outdoor activities, you can get everything you need from a pair of generation 1 goggles. Most of these goggles are for kids but if what you need is just to be able to see an image, a person or an activity in the dark, these types of devices are likely good enough for your purposes.

If you are looking for something more serious for professional use, consider an gen 2 or gen 3 device. These gen 3 military-grade night vision goggles from Armasight are a great choice, but they will cost you.

These Armasight goggles are primarily for those who plan to use them professionally. If you are just going paint balling, you probably won’t want to spend quite so much. Armasight does make somewhat less expensive gen 2 devices that are also extremely high quality and might be more suitable, if you are not going to use them professionally.

How Night Vision Works: Your Thoughts

Do you have any questions about how this works? Anything you’d like us to add to the article. Leave a comment below and let us know!

Night vision devices work on the principle of capturing the radiations which are invisible by the human eye. The enhanced spectral range allows the viewers to see the objects in the darkness. Night vision is now becoming necessary due to the usage of the technology in the betterment of human life. The usage of night vision cameras for surveillance purposes has increased its importance. People want to know more about the working, efficacy, and mechanism of night vision.

How do night vision cameras work

Many people have questions in their mind related to the visionary characteristics of the night vision devices. It is important to know through which objects night vision can see. The answer to this question is ‘yes’, night vision devices can see through a glass, walls, smoke, darkness, curtains, fog, and tinted windows. Night vision cannot see through absolute darkness but absolute darkness is very rare in our surrounding.

In this article, I will discuss whether the night vision devices can see through the objects mentioned above. Let us start our discussion: –

Night Vision through Glass

Yes, a night vision camera can see through glass. In the surveillance of a building or home, night vision cameras are places indoor and they see through the glass. Many people have this question in their mind while deploying a night vision camera indoor. You need to take some necessary measures for getting the effective results if your night vision device (NVD) sees through the glass. You need to turn off the IR and status lights for the mitigation of window reflection. It will help you to see through the glass or glass window screen clearly.

Night Vision through Walls

The NVDs work on the principle of capturing the infrared and ultraviolet rays and then amplifying them to show object in the darkness. In most of the cases, the answer to this question is ‘no’ as most of the walls of the buildings are thick enough to make insulation towards the infrared rays. In some cases, in which the walls are thin and they allow the infrared rays to pass, the NVDs can see through the walls. The police department of the US is researching the usage of NVDs for looking through the walls during their search operations. The military technologists are also working in this field and they are getting good results.

Night Vision through Smoke

Yes, the NVDs can see through the smoke. The wavelength of the IR rays is much longer than the wavelength of the visible light. The NVDS captures the rays coming through the smoke and make the images which could not be seen in the normal circumstances. Police and other agencies use the night vision devices during their operations in the smoky areas. It is good to keep your night vision goggles with you when you go towards the areas where the chances of rain, fog, smoke, and blowing sand are higher.

Night Vision through Complete Darkness

The answer to the question, whether night vision can see through the darkness, is ‘yes’. But, if there is no light, absolute darkness, then the NVDs would not be able to see the objects. Darkness means you cannot see anything with the naked eye while the absolute darkness means if there is no light at all. You must have to remember the difference in your mind before making any perception about the visionary characteristics of the NVDs. Absolute darkness is very rare to be achieved as most of the objects in our surrounding are above absolute zero body temperature.

Night Vision through Curtains

Can night vision see through curtains? The answer is ‘yes’, NVDs can see through the curtains. There are some limitations in this regard. The NVDs can only see if the infrared rays pass through the curtains. If someone is standing far away from the curtain then the NVDs would not be able to see the person. Many people have a question in their mind that whether the NVDs identify a person behind a curtain. The NVDs cannot identify a person as their resolution power is quite low. So, you can see through the curtains but it will be hard to get clear pictures. For security purposes, it is good to see through a night vision device. It will help you to identify if someone wrong is happening behind the curtains.

Can Night Vision See Infrared

The main purpose of the night vision devices is to capture the available light including infrared rays. The mechanism of image enhancement is used for the capturing and processing of the images in the night vision devices. The NVDs capture the available light and amplify it so that we can see what is going on in the darkness. Infrared rays are captured by the NVDs during its working.

Night Vision through Fog

The NVDs can see through the fog. The reason behind the visibility of the objects in the fog by the NVDs is their working principle. The wavelength of the IR and UV rays is longer than the visible light. NVDs can capture those rays and allows you to see through the fog. You will not get the clear pictures but you will be able to see the object up to some extent. In modern NVDs, visibility has been quite improved when you use the NVDs in the fog. Some night vision goggles are specially designed for the purpose of seeing through the fog and smoke. If you are interested in using the night vision for seeing through fog then you need to use those goggles.

Night Vision through Tinted Windows

The security cameras can see through the tinted windows of the vehicles. The energy waves can easily transmit through the tinted glass and it allows the security camera to capture the energy wave and process the image. So, you must have to be careful while driving a vehicle with tinted glasses on. You cannot be viewed the people on the roadside but you can be viewed by the security cameras mounted on the roadsides. The wavelength of the energy waves is much higher than the visible light and it can be captured from a larger distance as well. The IR cameras would not be able to see through the tinted windows in normal circumstances. Some NVDs are specially designed to see through the tinted windows.

Conclusion

Night vision has made it possible for us to see what we could not see in the past. We can now see through the glass, walls, curtains, and even tinted glasses. Is our privacy at risk if the night vision devices keep on improving? This is the main question at the moment. The security, surveillance, and other such purposes have made it possible to do what was thought to be impossible a few decades back. There are some positive and some negative aspects of the night vision. Night vision is banned in Germany due to its negative aspects. In the United States, night vision devices are not banned to be sold and people can use them. The NVDs cannot see in absolute darkness but in our surrounding, most of the objects are above absolute temperature and we can see them easily with the aid of an NVD.

How do night vision cameras work

Let’s start with a little background. Our eyes see reflected light. Daylight cameras, night vision devices, and the human eye all work on the same basic principle: visible light energy hits something and bounces off it, a detector then receives it and turns it into an image.

Whether an eyeball, or in a camera, these detectors must receive enough light or they can’t make an image. Obviously, there isn’t any sunlight to bounce off anything at night, so they’re limited to the light provided by starlight, moonlight and artificial lights. If there isn’t enough, they won’t do much to help you see.

Thermal Imaging Cameras

Thermal imagers are altogether different. In fact, we call them “cameras” but they are really sensors. To understand how they work, the first thing you have to do is forget everything you thought you knew about how cameras make pictures.

FLIRs make pictures from heat, not visible light. Heat (also called infrared, or thermal, energy) and light are both parts of the electromagnetic spectrum, but a camera that can detect visible light won’t see thermal energy, and vice versa.

Thermal cameras detect more than just heat though; they detect tiny differences in heat – as small as 0.01°C – and display them as shades of grey or with different colors. This can be a tricky idea to get across, and many people just don’t understand the concept, so we’ll spend a little time explaining it.

How do night vision cameras work

Everything we encounter in our day-to-day lives gives off thermal energy, even ice. The hotter something is the more thermal energy it emits. This emitted thermal energy is called a “heat signature.” When two objects next to one another have even subtly different heat signatures, they show up quite clearly to a FLIR regardless of lighting conditions.

Thermal energy comes from a combination of sources, depending on what you are viewing at the time. Some things – warm-blooded animals (including people!), engines, and machinery, for example – create their own heat, either biologically or mechanically. Other things – land, rocks, buoys, vegetation – absorb heat from the sun during the day and radiate it off during the night.

Because different materials absorb and radiate thermal energy at different rates, an area that we think of as being one temperature is actually a mosaic of subtly different temperatures. This is why a log that’s been in the water for days on end will appear to be a different temperature than the water, and is therefore visible to a thermal imager. FLIRs detect these temperature differences and translate them into image detail.

While all this can seem rather complex, the reality is that modern thermal cameras are extremely easy to use. Their imagery is clear and easy to understand, requiring no training or interpretation. If you can watch TV, you can use a FLIR thermal camera.

Night Vision Devices

Those greenish pictures we see in the movies and on TV come from night vision goggles (NVGs) or other devices that use the same core technologies. NVGs take in small amounts of visible light, magnify it greatly, and project that on a display.

How do night vision cameras work

Cameras made from NVG technology have the same limitations as the naked eye: if there isn’t enough visible light available, they can’t see well. The imaging performance of anything that relies on reflected light is limited by the amount and strength of the light being reflected.

NVG and other lowlight cameras are not very useful during twilight hours, when there is too much light for them to work effectively, but not enough light for you to see with the naked eye. Thermal cameras aren’t affected by visible light, so they can give you clear pictures even when you are looking into the setting sun. In fact, you can aim a spotlight at a FLIR and still get a perfect picture.

Infrared Illuminated (I 2 ) Cameras

I 2 cameras try to generate their own reflected light by projecting a beam of near-infrared energy that their imager can see when it bounces off an object. This works to a point, but I 2 cameras still rely on reflected light to make an image, so they have the same limitations as any other night vision camera that depends on reflected light energy – short range, and poor contrast.

Contrast

All of these visible light cameras – daylight cameras, NVG cameras, and I 2 cameras – work by detecting reflected light energy. But the amount of reflected light they receive is not the only factor that determines whether or not you’ll be able to see with these cameras: image contrast matters, too.

If you’re looking at something with lots of contrast compared to its surroundings, you’ll have a better chance of seeing it with a visible light camera. If it doesn’t have good contrast, you won’t see it well, no matter how bright the sun is shining. A white object seen against a dark background has lots of contrast. A darker object, however, will be hard for these cameras to see against a dark background. This is called having poor contrast. At night, when the lack of visible light naturally decreases image contrast, visible light camera performance suffers even more.

Thermal imagers don’t have any of these shortcomings. First, they have nothing to do with reflected light energy: they see heat. Everything you see in normal daily life has a heat signature. This is why you have a much better chance of seeing something at night with a thermal imager than you do with visible light camera, even a night vision camera.

In fact, many of the objects you could be looking for, like people, generate their own contrast because they generate their own heat. Thermal imagers can see them well because they don’t just make pictures from heat; they make pictures from the minute differences in heat between objects.

Night vision devices have the same drawbacks that daylight and lowlight TV cameras do: they need enough light, and enough contrast to create usable images. Thermal imagers, on the other hand, see clearly day and night, while creating their own contrast. Without a doubt, thermal cameras are the best 24-hour imaging option.

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  • Night Vision 101Night Vision DevicesNight Vision Generations and Viewing RangeImage Quality and Light RequirementMust Know

About the Author

Steve has never not known guns. Before motorcycles, money, or girls, they have always been part of his life. He was tenured as General Manager of one of the country’s largest gun stores and ranges, a buyer in a big box outdoor sporting goods store, and is currently OpticsPlanet’s Director of Product Intelligence. He was a US Navy nuclear gunners mate, a private investigator, and is an NRA certified instructor in ten categories, as well as an Illinois CCW instructor. He shoots competitively and has hunted from Alaska to Africa. He thoroughly loves life with his beloved wife, Shirley, and together they live with their three wildish dogs Tinker, TranRek, and Crash Almighty. He is a stubborn stage 4 cancer survivor and isn’t ready to cash in his chips yet.

Continue following Steve’s gun-laden lifestyle with never-ending firearm excursions and experiments with related products! Visit his blog page at Riflescopeblog.com.

    Night Vision

Night Vision 101

Night Vision Devices are electronically enhanced optical devices that enable us to see in near-total darkness. Even on a moonless night or in a dark interior, see everything within range of the IR illuminator.

Though Night Visions Devices (NVD’s) are very easy to use, technical jargon makes their literature tricky to understand. While any night vision equipment will greatly improve your ability to see at night, there are different grades of night vision goggles, night vision scopes, and thermal imaging cameras – from simple Gen 1 Night Vision monocular to an advanced Generation 3 Military Night vision goggles and rifle scopes – that will give you different levels of performance. While various digital night vision systems and thermal imaging cameras are becoming more available, the information about Night Vision presented below mostly focuses on how the most common night vision technology works – NV devices with various types of image intensifiers that convert weak light from the visible and near-infrared spectrum to visible light detectible by a human eye.

How Night Vision Works

Night Vision Scopes are sophisticated optico-electronic devices that assist viewing in near or complete darkness by amplifying all available light. Unlike telescopes and binoculars, night vision is usually not intended for magnification of remote objects (most night vision devices offer either no magnification 1x to very low 2x to 4x magnification).

Most night vision devices offered by OpticsPlanet.com include a built-in Infra Red (IR) Illuminator that acts as a “night vision flashlight” and provides additional light, making viewing in complete darkness a reality. A small red dot appears on the front of the night vision device when the IR Illuminator is ON. There are now Night Vision Blackout Infrared IR Filter Kits for Military Vehicles and even regular Spot Light Flashlights.

Choosing a Night Vision Device

The most common question in regards to night vision selection is “What is the difference between night vision generations?” All Night Vision products amplify existing light, allowing you to see in dark conditions too dark for the naked eye. Night Vision goggles, monoculars and binoculars collect and amplify existing light through the objective lens, which is then focused on the image intensifier. Inside the intensifier, a photocathode is “excited” by the light and converts the photon energy into electrons. These electrons accelerate across an electrostatic field inside the intensifier and strike a phosphor screen (like a green monochrome TV screen) which emits an image that you can see. It is the acceleration of electrons, which provides gain and enhances the image. The key difference between the night vision generations is the intensifier technology. Gen. I Night Vision devices use an intensifier tube that amplifies ambient light by accelerating electrons and striking a phosphor surface just like a Television. Generation II night vision devices add a micro-channel plate that multiplies the number of electrons before they impinge on the phosphor screen, thus increasing gain. Generation III Night Vision goggles, monoculars and scopes further add a Gallium Arsenide photocathode which creates significantly more photoelectrons than Gen II night vision devices. Generation 4 Night Vision is now offered by ATN. Generation II and III night vision devices offer greater light amplification, they are definitely better than Generation I, but a price beyond the reach of most buyers. Modern Generation I Night Vision devices are high quality and provide light amplification adequate for most recreational activities camping, hiking, fishing, boating, and nature viewing, and for many professional uses such as surveillance, search and rescue, and property management.

What Night Vision to Buy

When you are looking for night vision goggles or binoculars, choose the optical lens package, unit size and price that suits you best, and for most recreational use you normally do not worry about the slight differences in technical specifications. So many variables affect seeing in the dark. Some environments just soak up the light, particularly trees and dense vegetation. It is not possible to give exact, reliable performance specifications that will fit real life conditions. We can only list the technical capabilities. If you want to read up on technical details and see more details on technical details of image intensifier tubes used in night vision devices, please read our “HOW STARLIGHT TECHNOLOGY WORKS” article provided by ATN Night Vision (ATNcorp.com).

Refer to the GLOSSARY for definitions of terms.

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How do night vision cameras work

Infrared (IR) light is a wavelength of energy that is invisible to the human eye. The most common source of this energy is heat; objects can have their relative temperatures measured by how much of this energy they give off. Lower wavelengths or “near infrared” — closest to the visible light color red — are not hot, and are often used to transmit data in electronics. A remote control, for example, may use a particular wavelength of near infrared to communicate with a receiver, sending pulses of light that transmit a signal to the device, telling it what to do.

How do night vision cameras workAn example of thermal imaging, where the temperature of the object was captured with a special camera and represented with color in a photograph.

Description and Measurement

A form of energy, IR is part of the electromagnetic spectrum. This spectrum is comprised of radio waves; microwaves; infrared, visible, and ultraviolet light; x-rays; and gamma rays. Each form of energy is ordered by wavelength; infrared falls between microwaves and visible light waves because its waves are shorter than microwaves but longer than those of visible light.

The prefix infra comes from the Latin word which means “below;” the term means “below red,” indicating its position in the electromagnetic spectrum. Visible light has a range of wavelengths that are manifested in the seven colors of the rainbow; red has the longest wavelength and violet has the shortest. Infrared, with wavelengths longer than the color red, is invisible to the human eye.

Just like with visible light, there are a range of wavelengths of IR. The International Commission on Illumination has divided it into three general sections based on the length of the wave and density. These groups are commonly known as near, medium, and far infrared, with near infrared being nearest to the visible light side of the spectrum and far, or long-wave, being close to the microwave zone. There are uses for IR wavelengths in each group, from wireless communication to acting as heat source.

How do night vision cameras workInfrared lies between microwaves and visible light on the electromagnetic spectrum.

Applications

Nearly all objects emit heat or energy, and one of the most easily discernible forms of energy is infrared. When an object is not hot enough to give off visible light, it emits most of its energy in the IR spectrum. It is this heat that affords IR many applications in almost every sector of life, including health, science, industry, art, and entertainment.

Converting infrared energy, also known as radiant heat, into an image that the human eye can see and understand is done with a process called thermal imaging. An IR camera is used to accurately measure the temperature of an object, which is then translated into color. For example, infrared imaging typically shows the warmest areas in a human body as red, followed by yellow, green, blue, and violet as the temperature decreases. By studying how body heat is distributed, thermal imaging can health professionals to analyze body tissue and fluid to detect injury or disease.

Infrared light is used in night vision equipment, allowing the user to see in the dark. Two types of night vision both use IR: thermal and image-intensifying. Thermal night vision allows the user to recognize people and objects by the heat pattern they emit. Intensifiers amplify existing light — including infrared — to allow the user to see.

As a way to measure temperature, IR is used in many different types of applications. The military uses infrared sensors to locate and track targets or to detect hidden land mines or arms caches. Sensors on satellites are used for environmental monitoring, pinpointing areas of pollution, fire, or deforestation. Search and rescue operations use IR extensively to locate missing persons lost in the forest or jungle, as well as in collapsed buildings or at the site of other disasters.

Many remote control devices in homes use infrared. These remotes use this type of light to carry signals between a remote control transmitter and the device it’s commanding. The transmitter sends out light in pulses, which are translated into binary codes that have corresponding commands. The receiver is positioned on the front of the device, where it receives these pulses of light and decodes them into binary data, which is understood by the microprocessor inside the apparatus.

Many different types of scientists use infrared in their work, from astronomers use it to learn more about galaxies light years away to archaeologists who use it when studying ancient settlements. Infrared is being used to preserve, restore, and conserve valuable historical and artistic works as well; the invisible details of ancient fragments and images painted under paintings are being brought to light through the use of IR technology. In industry, thermal imaging is invaluable in testing and monitoring mechanical systems.

How do night vision cameras workVisible light has a range of wavelengths that are manifested in the seven colors of the rainbow.