Infrared vs thermal cameras: key differences, use cases and considerations

Thermal vs infrared cameras: the main differences 

The terms thermal and infrared are often used interchangeably in reference to video security cameras, but these two technologies are not exactly the same. All thermal cameras can be classed as a type of infrared camera, but not all infrared cameras capture thermal images.

When weighing the pros and cons of infrared vs thermal cameras, it’s important to remember the following distinction: infrared cameras are designed to identify and capture signs of infrared radiation (electromagnetic radiation featuring wavelengths longer than those present in visible light). In contrast, a thermal camera is a special type of infrared camera designed to detect infrared emissions and convert them into thermal images based on heat variations.

In short, all thermal cameras can be classified as infrared solutions as they’re able to capture footage of infrared emissions. However, not all infrared cameras come with thermal imaging functionality, with some models designed to produce different types of image visualizations.

How do infrared cameras work?

Infrared cameras, also known as IR cameras, are designed to identify and capture footage of infrared radiation, either emitted by or reflected off objects in their field of view. As all objects with a temperature above absolute zero emit infrared radiation, active IR cameras can detect movement or signs of suspicious activity that may not be visible on standard CCTV footage.

To produce viewable infrared images, IR cameras use a type of sensor called a Focal Plane Array (FPA). The FPA contains multiple detector elements that can each detect and measure the amount of infrared radiation they receive. This absorbed radiation is then converted into electrical signals, the strength of which will be directly tied to the intensity of the IR radiation. 

Each detector element sends a unique electrical signal to a linked processing unit, which will combine all the information into a single viewable image. Areas with more IR radiation show up brighter than those with less, enabling staff to ​“see” images regardless of light conditions.

How do thermal cameras work?

When comparing infrared vs thermal cameras for potential use in a security installation, it’s important to understand the slight variation in the way each solution captures images. While thermal cameras do detect infrared emissions similarly to IR cameras, the sensors utilized in a thermal camera solution are notably different from those present in a standard IR installation.

Rather than using FPA arrays, most thermal cameras today are equipped with microbolometer sensors. When IR radiation is detected by one of these sensors, the receptor will heat up accordingly. This reading is then converted into an electrical signal to produce an image based on heat variations, whereby colors represent the temperature of objects in the camera’s field of view.

With this in mind, the key difference between infrared and thermal cameras is that infrared cameras can detect and visualize objects based on the general levels of IR radiation they reflect and emit, while thermal cameras rely on visualizing stimuli in a thermal image and can see in complete darkness.

Key functional distinctions between thermal vision and infrared cameras

For business and property owners weighing up the pros and cons of infrared vs thermal cameras for use in security installations, it’s important to consider how the operation of each solution compares to the unique security needs of the business in question. While both types of solution can provide extra visibility over key assets when compared to traditional cameras, there are a few functional distinctions that may help leaders to settle on a preferred solution.

Visualization

In many ways, the primary difference between infrared and thermal cameras is the way each solution visualizes captured footage. In situations where security cameras are intended only to detect the presence of unauthorized persons entering private properties, thermal cameras may be most effective, as these solutions are specifically designed to detect heat signatures and can provide long-range coverage.

However, if security teams intend to reliably capture footage of suspicious activity in low-light conditions, including additional contextual information like appearances of people and vehicles or reading details such as license plates, infrared cameras will be more appropriate.

Image quality

Image quality is another important consideration when choosing any kind of video security solution and must be considered when making comparisons between these cameras. Both thermal and infrared cameras are available in various resolutions, with high-resolution solutions producing more detailed images. However, there are potential limitations to consider.

Primarily, infrared cameras will often produce clearer images due to their sensors picking up IR radiation as a form of light, meaning these cameras are better suited for night vision use cases. That said, thermal cameras with high-sensitivity sensors can detect smaller variations in the temperature of objects, effectively enhancing the quality of footage when processed.

Spectrum of operation

While both cameras are designed to detect infrared radiation, they do so by analyzing the infrared spectrum at different wavelengths. Thermal cameras can operate in the long-wave infrared spectrum (8−14 micrometers), meaning they can pick up variations in infrared radiation related to the temperature of objects in the camera’s view.

Comparatively, infrared cameras can operate in both the short and long-wave spectrums, picking up variations in infrared radiation across a much broader range of wavelengths. This enables IR cameras to accurately detect both emitted and reflected infrared radiation to provide a much more detailed image of objects passing through the camera’s field of view.

Cost considerations

As a general rule, thermal cameras are considered to be more expensive than generalized infrared cameras. This is mostly due to the cost of the specialized microbolometer sensors needed to accurately detect heat variations, which also require calibration to work effectively.

As infrared cameras cover a broader range of use cases, models can come in a variety of complexity levels, covering a larger number of price points. This means if property owners only need basic low-light functionality, an effective IR security camera will likely be more affordable. But comparable qualities of IR vs thermal cameras will likely be similarly priced.

Common use cases for thermal imaging

While understanding the differences between infrared and thermal cameras can aid leaders in determining which will be most appropriate for their installations, reviewing examples of each solution in action can help paint a clearer picture. Below are a number of common use cases for both thermal and infrared cameras to demonstrate where each device excels.

Building inspections

Thermal cameras are particularly useful for identifying heat loss in property maintenance settings and construction site surveillance; cameras positioned to cover key areas such as roofs, windows and plumbing systems can help teams identify areas in which thermal inefficiencies are present, helping facility managers to locate systems that may require more insulation or those that need to be repaired promptly.

Industrial maintenance

Another application in which thermal cameras are typically better suited than infrared cameras is industrial maintenance, specifically in detecting overheating components present in active machinery. Thermal cameras can be used to identify abnormal heating patterns that could signify mechanical or electrical issues that need attention, helping leaders address concerns before they impact operations
 

Property surveillance

Thermal cameras can help with physical intrusion detection in areas that receive little or no natural light, as well as environments with mist, smoke or foliage that could block the view of an infrared camera. Common examples include building or outdoor site perimeters where a small variation in heat signature may be easier to detect than the visible presence of a potential intruder, as well as storage spaces that may not be permanently illuminated by lighting systems.

Confidential security

In situations where privacy regulations restrict the operation of security cameras, thermal imaging systems can be of benefit. Footage captured by thermal cameras will detect the presence of individuals without revealing identifiable features that could lead to a breach of privacy rules. In this situation, infrared cameras would not be appropriate due to their ability to visualize IR radiation as visible light.
 

Common use cases for infrared imaging

Night vision

If the choice between infrared or thermal imaging cameras involves a desire to reliably monitor high-risk areas in low-light conditions, infrared cameras will almost always be the better option. IR cameras can not only detect the presence of unauthorized intruders in complete darkness but also produce images of a higher quality and with additional details to aid staff in identifying suspects more accurately.

Threat detection

Infrared cameras are typically preferred over thermal cameras in security systems designed to provide threat detection and response functionality. This is mainly due to the extra details IR cameras can detect with regard to factors like material composition, facial features and object identification, which enable infrared cameras to work alongside video analytics software to enact automated responses.

Vehicle identification

Infrared cameras can be used to track suspicious vehicles and recognize license plate information in low-light conditions, a process that cannot be performed accurately using thermal cameras. If installed CCTV cameras are intended to support vehicle monitoring initiatives 24/7, infrared solutions should be prioritized.

HVAC monitoring

Similarly to thermal cameras, some infrared camera models can be used to identify abnormal heating patterns in active systems. This means some types of infrared camera can also be used to support facility management teams in monitoring HVAC systems to ensure maintenance and repairs are performed reliably.

Infrared vs thermal cameras: final verdict

Both thermal and infrared cameras can be effectively deployed to enhance existing commercial CCTV camera solutions by ensuring usable footage is captured regardless of light conditions, but which is better? When choosing between thermal vs infrared solutions, business and property owners must first consider their own security needs, as this information will help to reveal an answer.

If business owners intend to develop systems used to detect the presence of unauthorized intruders, though they do not require these systems to produce detailed images of suspects, thermal cameras may be the most appropriate solution. This is especially true if teams wish to use newly installed cameras to monitor business equipment for signs of abnormal heating. 

However, if CCTV system upgrades are intended to provide security personnel with detailed images of suspicious activity in all lighting conditions, as well as support the operation of threat detection and vehicle monitoring systems through the night, high-resolution infrared cameras will likely be the better choice. Ultimately, while both types of security technologies can be utilized to enhance CCTV systems, the final verdict will depend on the unique needs of the business in question.