The purpose

Infrared cameras are used for a variety of purposes, including detecting heat leaks in insulation, providing 24/7 video security. Once you know the purpose for you camera there are some important considerations when it comes to the camera you choose including whether you camera will be used indoors or outdoors, the weather conditions, distance to the target, the size of the target and the maximum temperature to be measured.

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Indoor vs Outdoor Cameras

The primary consideration here is weather. You want to make sure you will instal a camera that is durable and can withstand the climate and weather conditions of you area. 

You will also want to consider the lighting. If you need that camera operating in both light and dark scenarios a great option is a regular camera with an infrared overlay. 

One last consideration is that some cameras perform just fine during raining or foggy weather while others cannot. Make sure you pay close attention to the camera details before purchasing.

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Distance to Target and Target Size

Camera and imagers are all bound by the same laws of physics in that in order to resolve a target at a distance you need to have an appropriate sensor and a suitable lens.

The term Instantaneous Field of View (IFoV) define this performance and is the “spot” size that a single sensor pixel project at distance through the lens. This spot size determines the smallest object you can see (resolve) at distance. People often ask,  “How far can you see with a thermal camera” ? And we say, you can easily see the moon ! So, its not just distance, but the size of the object you need to see at distance.

It’s a simple relationship in that the only items that determine the size of the object you can see at distance are the pitch of the detector (~ 15 x 10-6) and the focal length of the lens in mm. Research IFoV for more information.

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Maximum Temperature

Every thermal camera has it’s range in temperature, for human monitoring a standard camera will do the trick but for other functions such as high heat forging you may need to look specifically for a camera that can detect heat in that range. A good quality camera can detect around -40 degrees to up to 550 degrees Celsius.

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The Features.

Now we need to talk specifics on what features matter. The scale of the project will also help to determine what specific features you will need.

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Field of View (FOV)

The field of view is the maximum viewing angle of the camera (both horizontal and vertical). A wide field of view (WFoV) is best in applications where you want the best situational awareness, such as security. A narrow field of view camera (NFoV) is best when the camera is fixed onto a specific object or when looking at far away objects.

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Resolution and Memory Capacity

A big factor in a camera purchase is always the resolution. The higher the resolution the better the picture but the larger the storage files and the more delay in live stream cameras. 

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Display Features

Most infrared cameras come with some built in display features, in addition, there are features you can add in with additional software. A popular option is a standard camera image with an infrared image overlay (fusion). This type of image is generally easier to see while still showing the relevant infrared information.

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For security and surveillance there are some great target acquisition and tracking software. You can have you camera following moving targets that come into it’s FOV, record number plates of vehicles and send alerts when someone enters an area at a certain time.

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Sensitivity

Camera (thermal) sensitivity is measured by the ability to pick up the smallest signals. In daylight visible systems it is usually expressed in LUX, which is a measure of light, derived from the old candle power reference.

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Therefore, a camera with a light sensitivity of 0.001 Lux, will work better in low light conditions than a camera with a sensitivity of 0.1 Lux. In IR talk, we gauge sensitivity as Net Effective Temperature Difference that can be measure or resolved.

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This is the smallest temperature a camera can resolve as is expressed in mK°. Typical value for LWB uncooled detectors is 50mK and for cooled MWB detectors its around 25 mK. Research NETD for a more comprehensive explanation.

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Battery Life

Battery life is important for handheld case uses. Held held cameras a great camera especially if your job location changes frequently such as measuring for heat loss in insulation.

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Additional Considerations:

At this points you should have a good idea of what you’re looking for but before you buy a camera there are some crucial last things to consider.

The life expectancy of the camera should be considered when it comes to value for money. Along with this, the maintenance required on the camera should be considered. You may need to hire a service to routinely upkeep you camera for maximum performance (contact Infratherm to find a IR maintenance team near you).

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Another thing you may want to consider is future upgrability and attachments. While some cameras have a large range of attachments for most applications others are rigid and hard to upgrade.

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Finally, ease of use and the product learning curve is an important consideration. Check the camera reviews or contact an infratherm expert to get a good idea of the cameras ease of use.

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