An infrared camera is useful for a broad range of applications, ranging from maintenance to law enforcement use. While certain action movies may portray thermal imaging as some sort of magical device that can see through a house from a block away, the truth is that thermal imaging cameras have certain limitations.
If you are an owner of a thermal camera, or a prospective buyer, it’s helpful to know what these limitations are, and how to overcome them if possible. This results in a better understanding of what these cameras are capable of, while also managing your expectations for any desired uses.
Not all thermal camera limitations can be overcome, but many of the smaller issues can be addressed, leading to a much better thermal imaging experience, whether it’s for you, your employer, or a client.
Before discussing limitations, let’s first go over what thermal imagers are capable of with regular use.
First thing’s first: thermal cameras are not light cameras. They are not intended to capture a regular image that somehow also shows heat. Many infrared cameras do have digital camera capabilities as well, but this is mainly for providing context with a thermal image.
Infrared imaging is most successful when the object you are trying to capture is unobstructed. This means not behind a wall, door, or whatever else could be in the way. Any object in front of you that is capable of emitting electromagnetic radiation can be successfully captured with an IR camera.
Pipes, wall outlets, circuit breakers, humans, animals, window borders; all of these are prime examples of things you can accurately capture with a thermal imager. Higher-quality infrared cameras can capture incredibly detailed images from longer distances away.
Here are some common situations you may encounter that can affect your infrared camera’s ability to successfully capture an accurate, usable image.
One of the biggest limitations of an infrared camera is the fact that it cannot accurately capture an image through glass, or any other shiny object. Glass tends to reflect the heat of the object both in front and behind it, which greatly skews whatever image you are trying to get.
Glass can also block the thermal sensor in the camera entirely. So, basically the point here is to not try to capture an image of something that is beyond glass. Your only real option is to go around it, or go to the other side.
Sometimes your captured images may not seem very accurate, or display an image that is hard to decipher. For instance, you may may be trying to get an image of an area under a door that may be allowing heat from inside your home to escape, but you keep ending up with an image that doesn’t exactly show this.
The environment around you has a profound effect on how well your images will turn out. Infrared cameras are essentially used to show temperature discrepancies in the context of the field of view. Everything in the image is a comparison to what is around it.
You have several options when trying to get a better image in these scenarios. One of them is to simply try a different angle, or to get up closer to what you are trying to capture. Sometimes you may need to be further away. Trial and error is sometimes your best bet.
Another option is to try to alter the environment. If you are having trouble finding escaping heat from a home, try cranking the heat up further to provide a better contrast in the image. If you are using a more high-level thermal imager, you may be able to set a precise threshold that excludes readings of temperatures below or above a certain amount.
If the images you are getting that are still difficult to gauge, check to see if your camera has different color palette settings. Changing the colors to a gray scale or red scale may help you differentiate heat amounts better depending on the situation and object.
Images that are blurry and disheveled are common in many infrared cameras in certain scenarios. While many higher-level cameras are able to withstand blurriness with greater frequency, it can still happen.
Thermal cameras require a greater stability than a visual light camera. If your images are blurred, it’s likely due to shaky handling. The best counter for this is to remain as steady as possible, and give the camera a few extra seconds before trying to capture an image. This provides a much sharper image almost every time.
If your camera has a built-in digitial camera lens, you likely have the option to superimpose a light image with the thermal one. Sometimes thermal images can look like an outright mess until you see the image in context. Fuse boxes are a great example of this, manly because everything is so close together.
Infrared Cameras can certainly be used during the day in most scenarios, but the sunlight can cause plenty of noise in your thermal image, especially during the warmer months.
If you are working on a car engine and need to use a thermal imager to pinpoint a hot spot in the engine, you may get an obstructed image if you are in the garage on a hot day, or if the car has been recently driven. Allow the car to cool, or try to obtain an image during the evening.
Thermal cameras are very popular for inspecting roofs, but this can be very difficult during the daytime, especially when the home has standard shingles. The roof will be hot throughout, even on a cold day.
Many inspectors and contractors must wait or the early evening to try to capture images instead. This allows for a more accurate image without direct sunlight interfering with the heat radiating from the roof, or from inside the home.