Radiometric or not? Read before you buy your next thermal camera!

Thermal cameras, especially on drones, are becoming more vital in a number of industries. They are now being used to detect and prevent issues with equipment and infrastructure, for search and rescue operations, and even to catch criminals.

With so many different types of thermal cameras on the market, it can be difficult to decide which one is right for you. When choosing a thermal camera for your situation, there are several things for you to consider, including frame rate, resolution, focal length, radiometry, and more. One of the most important things to consider (and often the least understood) is Radiometry.

All thermal cameras display temperature differences in an area as visual images, but a radiometric thermal camera also records and displays the actual empirical temperatures of subjects.

From a non-radiometric camera image, you’re able to tell which areas on the image are significantly hotter than others; but without the radiometric capabilities you’re not able to get the exact temperatures.

So, should your thermal camera be radiometric or not? What are some common use cases that need radiometry and which ones don't? Is it worth the extra money?

To help you in your search for the perfect thermal solution for your use case, let's take a closer look at the differences between these two types of thermal imaging cameras.

 

Radiometric cameras are specialized tools that can take extremely precise temperature measurements. They work by detecting infrared radiation, which is emitted by all objects in proportion to their temperature.

By accurately measuring the amount of infrared radiation emitted by an object, a radiometric thermal camera can determine its temperature with extraordinary accuracy. In many cases, radiometric cameras can measure temperature to within minute fractions of a degree. This makes them an invaluable tool for applications such as medical, industrial and electrical thermal imaging, manufacturing process control, and scientific research.

In recent years, advances in sensor technology have made radiometric cameras smaller and more affordable than ever before, opening up new possibilities for a wide range of industries and applications when combined with drones

Some of the core advantages of radiometric cameras are:

The ability to take precise temperature measurements is critical in many scientific and industrial fields. This information is important as it can help to optimize processes, improve product quality, and protect people and equipment.

Oftentimes, having a precise record of temperature is necessary to ensure compliance with safety or quality regulations.

By detecting even small temperature changes, radiometric thermal cameras can be used to monitor a wide variety of processes and systems. A critical component of many inspection use cases is the need to constantly monitor for signs of damage or disease, so as to address the issue as quickly as possible and minimize the potential damage.

For example, radiometric thermal cameras are often used to detect leaks in industrial pipes, identify overheating electrical components, and track the movement and health of people or animals.

This information can be the difference between a proactive, preventative course of action, and a reactive course of action that seeks to repair the damage that could have been avoided in the first place.

Though they can measure the temperature of any pixel in the image in real-time, there is even more functionality to be had when the collected data is later imported into a computer for analysis. At that point, multiple temperatures can be measured, compared and analyzed for further information. This is very useful for process optimizations, and troubleshooting issues, as it gives more details about how different elements are interacting with each other.

Global and local object parameters can be set, which allows for strict temperature tolerances to be set for specific objects or regions. If the temperature of an object exceeds the set limits, an alert can be triggered to notify the analyst.

This functionality is often used in food processing to ensure that products are being cooked evenly and within the correct temperature range. It can also be used in industrial settings to monitor for overheating equipment that is operating outside of the established safety limits.

The ability to record temperatures for multiple (all) points in the image also means that they can be used to scan large areas very quickly. This heightened efficiency makes them ideal for tasks such as checking for hot spots in large arrays of solar or electrical equipment or monitoring the temperature of a manufacturing process.

So we've seen how useful radiometric cameras can be, but what about non-radiometric thermal cameras? What are the differences between the two?

As discussed earlier, the biggest difference is that non-radiometric cameras do not measure absolute temperature. While at a glance this might seem like a pretty big limiting factor, there are some advantages and use cases that make non-radiometric cameras the preferred choice.

Cost is a significant factor in most purchasing decisions, and thermal cameras are no different. Non-radiometric cameras are typically less expensive than radiometric cameras because they do not need to include the extra functionality required to measure absolute temperature.

This makes them ideal for applications where cost is a major concern, or in situations where radiometry is simply not necessary.

There are in fact many applications where thermal imaging is essential, but not the actual temperature measurements.

When it comes to law enforcement, there are a number of applications where thermal imaging can be extremely useful, but temperature measurements are not necessary. These include surveillance, suspect tracking, and human trafficking, among others.

In these cases, the focus is on detecting human bodies, rather than measuring their exact temperature. Once the presence of human bodies is detected, law enforcement personnel can then use other means to engage with the subjects.

Public safety is another application where thermal imaging can be very useful, but temperature measurements are not always necessary.

In search and rescue (SAR) situations, for example, the focus is on finding people as quickly as possible. In many cases, measuring the exact temperature of the subjects is not necessary. If someone is lost at sea at night, the temperature difference between the water and the person's body will be apparent and will make locating that person much easier.

Firefighting applications are another vertical where thermal imaging can be useful, but again, temperature measurements are not always necessary. In some cases, firefighters need to know the general location of a fire, but not the exact temperature. This information can be used to make strategic decisions about how to fight the fire.

This is especially important with brush fires, where "hot spots" can reignite without much visual warning. Having the ability to identify these areas growing in temperature allows firefighters to take action before the fire has a chance to spread.

Firefighting can also make great use of non-radiometric thermal cameras when it comes to fighting structure fires. From the outside, it can be difficult to tell where a fire is burning inside a building.

However, with a thermal camera, firefighters can quickly scan the exterior of a building and identify potential hot spots or dangerous areas through the walls or roof that would appear safe otherwise. This information can then be used to keep personnel out of harm's way and fight the fire most effectively.

Non-radiometric thermal imaging can be extremely useful for building and roof inspections. In many cases, building and roof inspectors do not need to know the exact temperature of the materials they are inspecting.

For example, if an inspector is looking for a potential problem with the insulation in a home, they can use a non-radiometric thermal camera to quickly scan the walls and identify areas where heat is escaping. This information can then be used to make repairs or take other corrective action.

The same is true for roof inspectors. In many cases, they just need to know if there are any areas on the roof that are significantly hotter or cooler than the surrounding materials. This information can then be used to identify potential problems, such as a broken sealant or missing insulation.

Thermal imaging can also be used to inspect solar panels. In this case, the focus is on identifying areas where the panels are not performing as well as they should be. This information is important in pinpointing the exact location of the problem so that it can be repaired.

The ultimate deciding factor in whether your application needs a radiometric thermal camera or not comes down to whether you need qualitative data or quantitative data.

Qualitative non-radiometric data can tell you that a temperature difference exists, or that there is a colder/warmer body on the scene. For general inspection and public safety applications, this is all that's needed.

But for more specific scientific or technical industrial applications, quantitative data is often required to make decisions or take action. In these cases, radiometric cameras are the better choice as they can provide absolute temperature measurements of any pixel in the image and allow for the analysis of exported data sets.

Clearly, there are a lot of factors to consider when deciding whether to get a radiometric or non-radiometric thermal camera. The most important thing is to match the capabilities of the camera to the task at hand.

If you need help deciding which type of camera is right for you, our team of thermal camera experts at Dronefly would be more than happy to assist you. Give us a call today!