Thermal Imaging: Everything You Need to Know

How can thermal imaging improve your life or add value to your business?

This is the question that many people should be asking, especially if they are involved in security, maintenance, and system monitoring of any kind. But, are you aware of the intricacies of technology and how to use it? Now is the time to learn!

Thermal imaging is a concept most people have heard of, but few understand entirely. This article covers what thermal imaging is, how it works, the benefits, and the limitations.

It also covers how thermal imaging was used in the past, how it’s used now, and how it may be used in the future. Use this information to decide if a thermal imaging camera system is the right choice for your organisation.

What is thermal imaging?

Thermal imaging requires thermal imaging cameras to translate heat (thermal energy), invisible to the naked eye, into a visible image. The image presented is used to analyse the environment and surroundings.

As all objects produce heat, living things and inanimate objects alike, thermal imaging cameras can detect activity, even in complete darkness. Only a very small amount of heat is required for a thermal imaging camera to work accurately.

It’s good to note that thermal imaging cameras with larger detectors deliver more pixels than a thermal imager with a smaller detector. For example, a thermal imager with a 320 x 240 detector delivers 76,800 pixels, whereas a thermal imaging camera with a 640 x 480 detector has 307,200 pixels.

Thermal imaging uses infrared radiation and thermal imaging to collect data on objects to create images of them, even when poor visibility is at play. Thermal imaging has many uses and is known for its role in night-vision technology and its ability to work in darkness or environments with fog, haze, smog or smoke.

How do thermal imaging cameras work?

Thermal imaging cameras work on thermography. The thermal imaging process is based on infrared energy, which is seen in the form of heat energy or a “heat signature” emitted from objects and surfaces. Heat signatures are invisible to the naked human eye, and thermal cameras can detect them even in low light or pitch darkness.

A thermal imaging camera, or a thermal imaging monocular as they are sometimes called, is a high-tech device that includes a heat sensor that is minutely sensitive to different temperatures. As the thermal imaging device gathers infrared radiation from surfaces in its environment, it creates a mapped out image depicting the differences in temperature presented in various colours.

Most thermal images are presented in black and white, aka greyscale. In greyscale presentations, white presents heat and black presents colder zones. The variations of grey depict fluctuating temperatures in between.

Modern FLIR thermal vision cameras present thermal imaging in full colour. With red, orange, and yellow depicting hot and warm zones and blue and green shades depicting cooler zones. Thermal imaging adapters from the likes of Pulsar (a leading supplier in the industry) also make it possible to ensure precise screen positioning and alignment during use.

Something to be aware of is that night vision monoculars or night vision goggles and thermal vision monoculars are different devices. That said, some brands on the market, such as ATN, produce both night vision and thermal vision devices.

To understand the difference between these devices, one must better grasp how night vision devices work.

Night vision goggles, night vision binoculars, night vision riflescopes, and various other digital night vision devices work similarly to the human eye. Night vision devices and the human eye (and regular daylight cameras) require visible light energy to hit an object and bounce off it. The detector receives the light energy and converts it to an image. Enough light is needed to create an image – if there isn’t enough light, the sensor cannot see.

Think of yourself walking in the pitch dark in a house with the curtains drawn in the dead of night compared with walking on a moonlit night. You can see more on a moonlit night than you can in the house because of the available light bouncing off objects. This means that digital night vision requires light, and in some instances, users incorporate an infrared illuminator.

While visible light and heat form part of the electromagnetic spectrum, thermal imaging differs from night vision. In fact, they aren’t really cameras but rather sensors.

FLIR’s, which are thermal imaging cameras, create images from heat and not from visible light.

Thermal cameras simply detect heat and the minute differences between temperatures.

What are the benefits of thermal imaging?

Thermal imaging is adopted as a maintenance strategy in various applications and industries where thermography is viable. These cameras enable people to see when they otherwise can’t and allow low-visibility video recording thanks to a high-quality thermal sensor often with long-range capabilities.

That said, let’s investigate the various benefits of thermal imaging below:

  • Thermal imaging is a safe method of measurement.
  • Thermal imaging enables accurate measurement of dangerous or hot machines to work with. Now tasks can be handled at a safe distance.
  • Businesses can save on operational costs as thermal imaging results in fewer power outages, less downtime, and reduced losses (as the malfunction is caught early on).
  • High-quality thermal imaging technology enables enhanced speed and accuracy in taking measurements of objects that are typically difficult to reach or in dangerous environments (underground mines, high power lines, etc.).
  • Thermal imagers make it possible to detect insulation issues, leakages, and irregular heat dispersion.

What are the limitations of thermal imaging?

What can thermal imaging do, and what can’t it do? For instance, can thermal vision see through walls and clothing?

First of all, thermal imaging cannot see through walls and clothing, but there’s more to think about when considering limitations. As with everything in life, thermal imaging comes with drawbacks and disadvantages.

Below is a list of the disadvantages of using thermal imaging devices.

  • Thermal imaging equipment may be expensive to invest in initially.
  • Thermal imaging cameras are not used underwater.
  • Thermal imaging cameras cannot see through walls and glass.
  • Emissivities and reflections can hider the accuracy of the temperature measurements taken.
  • Contact methods of measurement are more accurate. Thermal imaging cameras allow for around 2% leeway inaccuracy.
  • If an object has an erratic temperature, it can be hard to decipher the image presented.

How has thermal imaging been used in the past?

When was thermal vision invented?

To get to the bottom of this question, you need to consider the history behind the measurement of temperature. With a little digging, you will find that the history of thermal imaging is quite interesting to consider. Infrared is not a technology that’s always been available to us. It was quite limited in the very beginning.

The thermal imaging technology, or at least the concept thereof, was discovered in 1800 by Sir William Herschel. He was an astronomer trying to devise a filter he could use to study the sun without suffering the sun’s heat damage to his eyes.

During his experimentation, he discovered that invisible rays existed beyond what the human eye could see and that these rays exuded a temperature higher than ambient air. He called these rays “dark heat”, and it wasn’t until 1878, when Samuel Langley (astronomer and physicist) invented the bolometer, that more was achieved with this discovery.

Bolometers are thermal imaging binoculars that can detect electromagnetic radiation by absorption of radiation. At the time, the device could measure infrared to 1/100,000 of a degree, with enough magnification to see clearly from a distance.

After much advancement and experimentation, the first infrared camera was developed in 1929 for use by the British army after World War II for anti-aircraft operations. After that, thermal imaging technology became an essential part of defence strategies.

By 1947, the thermal camera was able to take still images, but this process would take around 60 minutes per image produced. Over the subsequent years, the speed and accuracy of the camera have greatly improved.

It was evident that thermal imaging cameras played a role in science and defence in the past. Even in its early years of adoption, the technology was helpful to police, firefighters, and rescue personnel. Hunters and hobbyists also found great value in investing in thermal vision devices but to a limited degree.

Towards the end of the 20th Century, getting a thermal imaging device became far more affordable. With the dawn of lower prices and easier accessibility, the thermal vision became possible in the following applications and sectors:

  • Inspection of buildings for damaged pipes, leaks, and insect infestations.
  • Detecting irregularities in blood flower, certain cancers, and inflammation due to medical diagnostics.
  • Tracking people and unauthorised access such as illegal border crossings or criminals on the run.

New thermal devices are hitting the market consistently, and we can only expect the systems we now know to be even more advanced and functional in the near future.

How is thermal imaging being used today?

Nowadays, thermal imaging is no longer a novelty. It is a viable avenue for various industries to improve efficiency, boost productivity and ensure that the tasks at hand are handled meticulously.

Since its invention, thermal imaging has come a long way, with multiple industries using thermal night vision cameras to varying degrees.
With the release of the FLIR One in 2014, there’s been a definite rise in the adoption of thermal imaging cameras, which are now readily adopted in private homes and businesses.

For instance, let’s consider the inclusion of thermographic devices in vehicles that use thermal imaging technology. These cameras help drivers detect possible objects that may cause a collision by sensing the heat signatures of objects, people, and animals.

In addition, most heat signature cameras are supplied with a one year warranty from the date of purchase.

Below is a list of how thermal imaging cameras are used today:

  • Law enforcement
  • Business surveillance
  • Military operations
  • Infrastructure inspection
  • Firefighting
  • Marine
  • Search and rescue missions
  • Livestock and agricultural monitoring
  • Aerial photography
  • Building maintenance inspections
  • Mining industry (fire and gas detection)
  • Hunting
  • Aerial photography

These are just a few of the ways that thermal imaging cameras serve a purpose.

What are the future applications of thermal imaging?

Currently, thermal imaging is used in many industries. The tech has been well-adopted by the world, but that doesn’t mean that the full potential of thermal imaging has been realised. In fact, there’s a lot more in store for the technology and its associated devices.

Rumour has it that advancements are already underway with new modules of thermal devices soon to hit the market for Android and Apple devices with Wi-Fi adaptors to ensure that they’re truly smart.

Below are a few ways in which future applications may use thermal imaging.

  • Self-driving vehicles

Self-driving cars can be made a lot safer by incorporating thermal imaging cameras. These cameras will ensure that vehicles can make better decisions at night, even in poor weather conditions and in low light. In addition, thermal imaging can detect objects that regular cameras wouldn’t be able to in poor conditions.

  • Police services

Drones can be used to pursue criminals on the run and monitor situations from the sky, aiding police.

  • Fire fighting

Thermal imaging cameras can be used with drones to provide aerial photography on fire outbreaks but also used to detect fire in buildings, in underground cavities, in wall cavities and so on.

  • Smartphone applications

A mobile device equipped with modular thermal cameras can be used to monitor heat loss, making system surveillance and general maintenance tasks easier.

  • Military defence

Thermal imaging drone cameras can be used to detect unauthorised aircraft systems and even be set up to eliminate them.

  • Disease control

Thermal imaging scanners can be used to determine if an individual has been in contact with a contagious disease. The technology can also effectively detect certain types of cancer, such as skin and breast cancer.

While these systems are in their infancy already in everyday life, it is expected that we will see significant advancements very soon.