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Understanding Night Vision / Infrared CCTV Cameras

FLIR and Security IR Camera Confusion

First shown on tv and in crime and military movies, the garish yellow, red, green and purple display from the FLIR (Forward Looking Infrared Radiometer) camera one thinks of when many people think about “night vision cameras”. FLIR cameras have a very expensive video sensor array (and support circuits) that detects infrared emissions from any area where the camera is pointed. Any living person, animal, or object generates (emits) small quantities of infrared light. Hot objects emit more IR light than warm and cool objects/areas respectively. The difference is inside the amount of IR light emitted means the colors shown over a FLIR display.

FLIR cameras are employed in a wide variety of private, industrial and commercial settings. Consumers and professionals use them commercially for safety, building inspection, emergency and hazard prevention and identification. The real-time display on many FLIR camera designs gives the user immediate feedback and enables them to pinpoint and correct issues that are often invisible on the naked eye. Subtle variations in temperature can even allow contamination being detected in all kinds of materials, including food.

Since physical contact isn’t needed, FLIR devices can capture and monitor temperature readings from distant objects that you will find inaccessible or even dangerous to approach (such as bearings in a working turbine or fixtures and objects in contaminated areas which might be dangerous to the health of human workers).

The other type of infrared camera – what type that make up the backbone of surveillance systems in millions of buildings around the world – is less flashy but more a great deal more cost effective. This type of camera possesses an infrared sensitive video sensor somewhat just like a FLIR camera, but is a much cheaper variant. Most importantly, instead of depending on the weak infrared light generated by warm objects, IR video cameras depend on reflected infrared light.

Since there is not enough ambient infrared light even around the hottest and brightest
days, cameras that depend on reflected IR light require a LOT of IR light to operate. That is why many IR security cameras contain a built in assortment of infrared LEDs or require an outside radiant IR source.

Todays Consumer IR Cameras

Every one of the IR security camera products we supply fall into the second group of IR camera. They aren’t FLIR type cameras. Since they be determined by reflected IR light, most of our cameras include a built-in radiant IR LED array – those that do not require an external way to obtain IR for imaging in the evening.

Night-time imaging in the world of IR security cameras is essentially black-and-white (monochromatic) imaging. Throughout the day and when light can be obtained these cameras produce a color image. In the event the amount of light drops into a preset threshold the digital camera automatically switches to infrared mode. Night/day cameras stretch the brink a bit by using a very sensitive video sensor and can still produce color images in extremely low light but unless the camera can be IR sensitive it is going to stop working when zero light can be acquired no matter how good the low-light video sensor. Take into account that even at nighttime you will find there’s normally some light from nearby signs, street lamps, and in many cases the stars and the moon, so in many situations a good night/day camera can be preferable to an IR camera.

The similarity between night/day cameras and IR cameras ends here.

When visible light drops below its preset threshold an IR camera switches to IR mode. Whether or not this has IR LEDs, they come into action. Video output becomes black-and-white. The high quality, sharpness, and the range of which a picture can be “seen” with the camera depends on the volume of IR light available and of course the camera’s lens, kind of video sensor and support circuits.

Bad Cameras, Good Cameras, and Dirty Pictures

The lowest priced way to insure good IR mode video would be to flood the area with all the IR light as you can. This is usually done by powering up banks (arrays) of IR LEDs. The quantity of IR LEDs is limited by physical factors. IR LEDs may be large or small and manufacturers can be quite ingenious in packing as many as possible into a small a location as possible. But IR LEDs may cause their own problems, chief most notable is heat and glare. Heat destroys electronic components after a while.

Mr Surveillance in Sacramento (916) 550-4386

Our cameras beat “heat” problems using a variety of methods for example careful design, material selection and construction, venting as well as cooling fans. Glare occurs IR light in the LEDs strikes inside protective covers or glass and bounces into the lens creating “IR haze”. This will make images appear less distinct or creates unwanted dark/light patches. Our cameras defeat IR haze using special coatings, design techniques, special materials and integrated lens separators that physically isolates the lens from your IR LEDs.

It is possible to identify a cheap IR camera with the presences of a foam ring glued to the inside surface of the glass so that you can surround the lens with an IR light block. This is not just less effective, but when the foam breaks down over time and crumbles to the interior of the camera coating every one of the parts (including the lens) using a fine black dust/grit. You can think of how that affects image quality in day or night modes.

Along with methods already mentioned, we employ yet another technique to insure IR video is usually high quality – an aspherical lens. It will help to eliminate the phenomenon referred to as “focus shift”.

“Focus shift” happens when a camera is targeted using visible light, and it is then used through the night (in IR mode) without adjusting the lens. The IR light-only image will be slightly fuzzy when the camera lens just isn’t adjusted. This is because IR light, as being a different wavelength than strikes, visible light, and travels through the lens slightly differently than visible light (that has been used to originally focus your camera). To bring an IR light-only image into focus an adjustment must be made manually if the spherical lens can be used. Obviously this is a problem if your camera is in an online location or for the ceiling where you can’t reach it with no ladder. An aspherical lens, thanks to it’s non perfect sphere shape, is capable of refocusing IR light automatically.

Our Infrared CCTV Cameras

Our IR cameras offer you the best and most affordable means to increase your personal safety and property the reassurance of residential or commercial belongings. Video quality is consistently high in day, night, and in-between. With only a slight increase in total cost, using IR cameras rather than non-IR cameras can provide superior peace of mind in nearly every surveillance network.