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Fixing problems you can see is often easier than fixing those problems that you cannot see. Thermal cameras are used to locate and monitor temperature differences in many systems. You may wonder what thermal imaging is and how thermal cameras are used. This post answers these questions.
You can also read up on the history of thermal imaging cameras and the benefits of using thermal imaging technologies. In addition, this post discusses how to choose the right thermal imager.
Thermal Imaging Explained
Thermal imaging is a process that lets you see the amount of heat an object radiates off itself. You can use the temperature difference from thermal imaging to identify, measure, and visualise heat patterns, especially in environments lacking visible light. The thermal cameras detect and capture varying levels of infrared light.
Hotter objects tend to give off more infrared radiation. Thermal cameras also record the temperature and assign a shade of colour to each temperature. Ultimately, thermal cameras convert the radiation into a visible image. In this way, you can assess the amount of radiated heat an object emits compared to objects around it.
Thermography is a term that refers to a diagnostic method that detects the surface temperature of objects. It uses a non-invasive approach that records infrared (IR) radiation emitted from the object. The infrared irradiation is then visualised within a temperature distribution map.
The “thermogram” or resulting image is then analysed to identify electrical or mechanical faults. You can also use it to determine human and animal structural defects and physiological changes. This is why thermal imaging has excellent applications in building diagnostics and industrial applications.
Infrared imagers and thermal imagers explained
A thermal imager device uses a non-contact temperature measurement and data acquisition approach to detect infrared energy. These infrared energies are heat signatures that may be emitted, transmitted, or reflected at temperatures above absolute zero (0°Kelvin).
The energy factor is converted into a temperature reading (thermogram). In addition, the camera produces an electronic image from the converted infrared data. This image indicates the temperature of the object you are measuring.
The field of view explained
The field of view refers to the angle of vision your instrument operates on. This machine vision depends on the optics of your unit. The target you are measuring needs to fully occupy the field of view of your instrument for you to get an accurate temperature reading.
The Role of Thermal Imaging Cameras
Thermal imaging cameras or infrared cameras precisely capture images in the infrared spectrum. Other names for thermal imaging cameras include thermographic cameras, thermal scanners, and FLIR cameras.
Thermographic cameras are known to detect radiation in the electromagnetic spectrum. This means that they produce images of the radiation as “thermograms”. Other examples of infrared imaging science besides thermographic cameras include infrared thermography and infrared video.
History of Thermal Imaging Cameras
The origin of thermal imaging is not entirely clear. However, the present form of thermal imaging was previously developed for use in the Korean War.
The invention of night vision cameras
The night vision or infrared-sensitive camera was invented in 1929 by a Hungarian physicist for Britain’s anti-aircraft defence.
The first American thermographic camera
Infrared line scanners were the first American thermographic cameras that were developed.
Improvements in early thermal cameras
From the 1950s to the mid-1990s, improvements were made to the first thermal imaging cameras. Cooled focal plane arrays were standard in the mid-1990s. Today, there are both cooled and uncooled focal plane arrays. Likewise, thermal imagers have current applications in building inspections, robotic and machine vision, and security surveillance.
Small temperature control elements are used today to stabilise temperature sensors close to ambient temperature. This is applied in uncooled thermal cameras. Meanwhile, such modern uncooled detectors use level measurement sensors that measure resistance, voltage, or current as heated by infrared radiation.
Detected changes are compared to operating temperature values based on the spectral range of the imager. Regenerative cooling systems need good pressure measurements for the supply of pressurised gas. Naturally, multifunction calibrators, including temperature and pressure calibrators, need to be used regularly to verify the accuracy of sensors.
Benefits of Using Thermal Imaging Technologies
If you look at various industry sectors, you will find that thermal imaging technologies are used in many ways. For instance, thermal imaging technology has predictive maintenance and condition monitoring (CM) applications.
Quality inspections to reduce downtime
In instances where temperature plays a key role, IR thermal imaging provides the most effective tool for predictive maintenance. Thermal imaging is both non-contact and non-invasive.
As such, thermographers can perform thermal analysis inspections even when the plant or equipment runs fully. In other words, you can better ensure maximum equipment uptime using such condition monitoring features.
Accurate and timely temperature measurements
You can use thermal imaging surveys to get temperature distribution measurements of surfaces of electrical equipment under normal load conditions straightaway.
Non-invasive thermal imaging cameras (infrared cameras)
Thermal imaging cameras are also known as infrared cameras and are 100% non-invasive. As passive instruments, they can detect infrared energy emitted from surfaces. This non-invasive approach allows thermographers to keep a safe distance and avoid hazardous exposure or equipment damage.
Likewise, thermal imaging surveys provide early detection that allows for timely intervention to prevent possible hazardous equipment failure. You can use thermal imaging to reduce the risk of melting wire and cable in an electrical system. These, in turn, help to improve personal safety and fire safety.
Better regulatory compliances
Infrared thermography and associated thermographic surveys help you meet the risk compliance requirements. Performing regulatory compliance processes relating to health and safety legislation and insurance-related risk assessments and prevention becomes easier.
Thermal Cameras Vs. Spot Infrared Thermometers
Regarding thermal imaging, spot infrared thermometers can present a single temperature at one spot. However, thermal imaging cameras can provide the entire picture, sometimes up to 19,600 spots.
From the images that thermal imagers provide, you will be able to see hot spots as well as the temperature difference of the object. Thus, thermal imaging is a very effective method for diagnosing potential problems in different applications across many fields.
Uses of thermal imaging
There are common basic engineering applications of thermographic imaging today. This is in addition to using thermal detection cameras for emergencies.
Electrical maintenance uses
Power line technicians can use thermal imaging to locate joints and components that have the potential to overheat. Such sections tend to emit thermal heat more than other sections.
Plumbers can use thermal imagers to detect gas and water leaks in walls and pipes. You can more easily use the devices to discover problems at a distance in hard-to-reach areas. In addition, thermographic imaging can help you quickly locate air leakage if you work with thermal insulation.
Consequently, you can better maintain and regulate temperature and spot heat loss from walls. Similarly, you can use thermal imaging to reveal various kinds of air leaks in heater ducting or air conditioning systems.
Thermal imagers have a comparative advantage over night vision devices in that bright lights do not affect them. Moreover, they do not require ambient light. That is why they are of great use in surveillance equipment to locate suspects at night and for rescue operations.
Checking for Circuit Board Defects
You can use thermal imagers to assess printed circuit boards for electrical defects as an engineer or technician.
During restoration works
You can use IR cameras to confirm whether restoration work performed has successfully solved moisture problems.
Infrared non-destructive testing (IR NDT)
You can use this process to detect water incursions or voids in composite materials.
Detection of skin temperature variations
Skin temperature variations can indicate or be symptomatic of various underlying medical issues. IR cameras are a useful non-invasive option to help detect these variations.
Thermal imaging techniques have been used to survey animals in the wild. Thermal radiation can penetrate dust, mists, and smoke more effectively than visible radiation. Thus, you are more able to detect and monitor animals over a wider range of atmospheric conditions using infrared thermal cameras.
It is even possible for researchers to use infrared imagers when studying animal physiology. For instance, they can locate and monitor thermal abnormalities in various anatomical parts.
An advantage of thermal imagers over the usual visible aerial photography is the ability to sense heat. This is applied when mapping solar radiation absorption and thermal energy in various soil types.
Crewless aerial vehicles (UAVs)
Unmanned aerial vehicle-based detection systems can have modern agricultural applications when the thermal signatures of the detected objects are studied.
Multiple applications of thermal videos
Cutting-edge technologies exist today, such as smart sensors that measure temperature and humidity levels. Various data loggers regularly use temperature sensors. Incorporating smart sensors and WiFi connectivity into thermal video cameras makes them handy in professional engineering repair.
Emissivity and Infrared Temperature Measurements
Emissivity, as a term, refers to the ratio of energy radiation of an object at a specified temperature to that emitted by a black body or perfect radiator at roughly the same temperature. Objects usually have emissivity values between 0.0 and 1.0, while a blackbody has an emissivity value of 1.0.
Emissivity has a direct relationship with infrared temperature measurements. An object with a higher emissivity value tends to give a more accurate temperature measurement using infrared. Regarding thermal infrared imaging, the thermal radiation emitted from natural materials depends on their emissivity.
How to Choose the Right Thermal Imager
Buying a new thermal imager goes beyond filling out product registrations. Before choosing the right thermal imager for your application, you must consider the specifications.
Infrared cameras vs. visible light cameras
Your infrared camera should have the highest image quality and detector resolution to allow you to measure smaller targets at greater distances. This will help you to create sharper thermal images and get more precise and reliable measurements.
However, many infrared cameras have fewer pixels than visible light cameras. Thus, you should properly check the detector resolution. A practical alternative is a thermal imaging system with a built-in visible light camera, an illuminator lamp, and a laser pointer.
Check out Bluetooth and WiFi features
Your thermal imager is a test and measurement tool that transmits important diagnostic data directly to the camera. Such test leads include relative humidity, voltage, amperage, and resistance.
The data is automatically annotated and embedded as a thermal image in the radiometric JPEG. You may need to send the thermal images and IR inspection reports to other places quickly. This process is more straightforward with the use of WiFi and Bluetooth features.
The camera’s temperature range and thermal sensitivity
The temperature range is an indication of the minimum and maximum temperatures that your camera can measure. Getting a thermal camera with a wide temperature range is more beneficial. A typical camera temperature range is -20°C to 1200°C.
Professional Help with Thermal Imaging
After reading this blog post that discusses thermal imaging, you may have recognised the usefulness of thermal imaging for preventive and corrective maintenance. An experienced electrical contractor can help you with preventative maintenance (for fire detection purposes), troubleshooting, installation, and home inspection services. Thermal cameras aid in these tasks, and you can invite your local electrical contractor to install them.