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What is a thermal imaging camera? Thermal cameras or thermographic cameras are devices that translate thermal energy (heat) into visible light (color) to analyze a particular object or scene. The image produced by thermal imaging cameras is known as a thermogram and is analyzed through a process called thermography.
How do they work? Almost all objects radiate thermal energy from their surface. Modern thermal imaging cameras use a detector called a microbolometer to detect this thermal energy. Microbolometers are made up of an array of pixels that are made from a variety of different materials, most commonly amorphous silicon and vanadium oxide. When thermal energy emitted by an object hits the pixel material, the material heats up, changing its electrical resistance. This resistance can be measured and translated into a temperature value. A thermogram is then produced by assigning colors or shades to each of these temperature values.
What do I look for when buying a thermal camera? There are numerous components that contribute to both the quality and cost of a thermal imager. The two most important factors are detector resolution and thermal sensitivity.
The detector resolution describes the number of pixels in the microbolometer array. The most common detector resolutions are 160X120, 320X240 and 640X480 pixels. These values represent the number of horizontal pixels times the number of vertical pixels in the array. A 320X240 detector produces an image composed of 76,800 pixels. Since each pixel has an associated temperature, there are also 76,800 temperature data points. Higher resolutions also produce visibly clearer images (similar to digital cameras).
Thermal sensitivity is the smallest temperature difference that the camera can detect. A sensitivity of 0.05°C means the camera can distinguish two surfaces with just five-hundredths of a degree difference in temperature.
What features can I expect to find in a thermal imager? All of the portable imagers we carry capture images to an included memory card which can then be transferred to a PC via the USB interface. Each imager includes software that allows the user to analyze the images and create a report. As with most electronic devices, there are certain features or “selling points” that can make one imager more attractive to a potential user than another. Our thermal imaging comparison chart highlights these differences (link here). Here are some to look for:
Built-in digital camera Field of view and the ability to add lenses (telephoto, wide angle, close-up) Video output to another device, such as a computer, TV or projector. Imager LCD screen size Refresh rate (how fast the image updates, 60 Hz = 60 updates per second) Touchscreen capability Ability to auto- or manually focus the lens Ability to add voice/text annotations Rugged design and ergonomic Who manufactures thermal imaging cameras and infrared cameras? We have three main manufacturers of thermal imaging cameras and infrared cameras: Flir, Fluke and Testo. Each manufacturer offers different designs and functionality to best suit your application.
Flir has been in the thermal imaging business for over 30 years. For the first twenty years, their cameras were used primarily in government and military applications, including aircraft, marine, and law enforcement. As the cost of manufacturing has decreased in recent years, Flir has been able to offer cameras for a wide range of applications at a variety of different price points.
Fluke has been designing and manufacturing test and measurement instruments since 1948. Fluke is known for its reliability and rugged design, built for the most demanding industrial applications. All Fluke thermal imagers are made in the United States.
Testo has a very strong presence in the HVAC market, especially with combustion analyzers, anemometers and humidity products. Their imagers offer excellent value as well as great performance in a variety of different applications.
How can I use my thermal imager? Now that you have a brief understanding of how thermal imaging cameras work and what to look for, let’s look at some common applications.
Home inspection and energy audits Thermal imaging cameras can be used to scan buildings for heat loss, moisture damage and other costly failures. Imagers used for building inspections generally do not require larger temperature ranges, but do require high thermal sensitivity. Imagers that are well suited to these applications are Flir i7, E30bx, E40bx, E50bx, E60bx, T300, Fluke TiS, TiR, TiR1, TiR32 and Testo 875-2i, 881-1.
Electrical and mechanical inspections Thermal imaging cameras are ideal for preventive maintenance of electrical and mechanical equipment. Excessive wear, overloading, and defective parts can generate visible heat for an imaging camera. High resolution, wide temperature ranges, and high sensitivity are critical for these applications. The cameras that are best suited for electrical and mechanical inspections are the Flir E30, E40, E50, E60, T300, T620, Fluke Ti10, Ti25, Ti32 and Testo 875-1i, 875-2i, 881-1.
Research and development Heat is often a limitation in the development of processes of all kinds. Thermal imaging cameras can help in the production of systems and products by pinpointing potential problem areas. High resolution is a must for these applications, so the Flir E60, T300, T620 and Fluke Ti32 are good choices.
Medical and veterinary High-resolution imagers are capable of providing information about medical conditions in both humans and animals. Injuries and illnesses often create additional blood flow to affected areas. This flow of blood, if close enough to the skin, generates heat detectable by thermal imaging cameras. Imagers to consider for these applications are the Flir E60, T300, T620, and Fluke Ti32.
There are many applications for thermal imaging cameras that have yet to be discovered. Feel free to ask which cameras can help with your application.
As with all products we sell, we encourage you to call us and speak with one of our engineers. We currently have two Level II certified thermographers who are eager to discuss your application and help you get the best camera for your needs.