Range of Thermal Cameras - Current Market Overview from a Professional Perspective

Steps for Selecting a Thermal Camera, Requirements Table by Profession

Thermographic devices suitable for contactless temperature measurement (infrared cameras with thermographic capabilities) have undergone rapid development in recent years. Considering that these devices appeared just 50 years ago, but have now grown into one of the most well-known and versatile inspection tools, it is no surprise that the market offers a wide variety of options (manufacturers, types). For a customer planning to purchase a thermal camera, the issue is no longer the lack of a suitable type according to their needs, but rather the overwhelming variety of choices available. Therefore, it is time to review the development and types of these instruments from a professional perspective, and organize the current selection based on some important technical parameters. Because: The measurement technology implemented in the cameras and the accessories available determine the device's application area, as well as the expected measurement accuracy and the quality of the thermal image that can be obtained.

Step-by-Step Thermal Camera Selection

The sequence of criteria for selecting a thermal camera that meets the specific thermographic measurement task is as follows, taking into account the current range of thermal cameras:

0) Installed or Mobile?

Not applicable for installed thermal cameras: - for handheld measurements, as they do not have a battery, controls, or a built-in display (carrying a continuously connected notebook is not practical) Not applicable for portable thermal cameras: - for installed tasks where cooling/heating, moisture, and dust protection of the thermal camera are required, as protective enclosures of this kind are typically only available for installed types

1) Wavelength Range

Not applicable for the long-wave range: - only for objects with high emissivity in the mid-wave range - if there is glass (or other materials that do not transmit long waves) between the object and the thermal camera Not applicable for the mid-wave range: - for measuring low-temperature objects - for measurements from large distances (several times greater than 10 m) - only for objects with acceptable emissivity in the long-wave range - for materials between the object and the thermal camera that do not transmit medium wavelengths

2) Detector Technology considerations: wavelength, frame rate - bolometer/microbolometer sensor can be used if: - a long-wave device is needed and - a maximum of 50/120 Hz (or up to 240 Hz for special thermal cameras) frame rate is sufficient (Note: For freehand thermal camera use, to avoid problems caused by motion, a minimum frame rate of 50 Hz is required) - photon detectors are required if: - measuring in the mid-wave range (e.g., through glass) or - a frame rate above 50/120 Hz (or in exceptional cases 240 Hz) is needed (Note: Photon detectors are significantly more expensive than bolometers and also require cooling, which depending on the technology, imposes a lifespan limit.)

3) Thermal Resolution to be considered based on the specific task - not critical for checking boilers and furnaces, or assessing mechanical or electrical equipment, as faults/thermal phenomena involve large temperature differences - important for searching for moisture/leaks; assessing insulation, fire-resistant linings (wear) - usually the most crucial parameter for biological or material testing (Note: Improving thermal resolution provides sharper, clearer, and more recognizable thermal images.)

4) Temperature Measurement Range to be considered based on the specific task - important quality parameter, especially for measuring low-temperature objects

5) Number of Pixels - absolute minimum: 160 x 120 pixels (effective work is hardly possible with fewer pixels) - recommended minimum: 256 x 256 or 320 x 240 pixels - economical: 384 x 288 pixels - professional: 640 x 480 or 640 x 512 pixels - current peak: 1024 x 768 pixels - favorable solution: quadrupling pixels with microscan (up to 1280 x 960 or 2048 x 1536 pixels) (can be used with or without a stand; not interpolation calculations, but real measurement points) (Note: The more pixels the camera has, the more details become recognizable in the image or the larger object (equipment) can be examined at once with adequate (evaluable) resolution.)

6) Geometric Resolution - to be considered based on the specific task - for multiple tasks, it is preferable to choose a thermal camera with interchangeable lenses so that the appropriate geometric resolution is always available - a favorable solution without interchangeable lenses: quadrupling pixels with microscan, improving the geometric resolution to 2/3 of the value specified for the same detector/optics assembly

7) Special Capabilities - rapid internal storage of thermal image sequences without a PC - remote control, live data transfer - interchangeable lenses, special filters

Criteria for Task-Specific Selection of Thermographic Devices

Professional Field	Spectral Range	Technology	Calibration Range	Number of Pixels	Geometric Resolution	Thermal Resolution	Frame Rate	Recommended Functions/Accessories
Building Thermography	8…12 µm	Bolometer (Photon detector also good, but expensive)	min. -20°C … 100°C better from -40°C (approximate upper limit)	min. 320×240 better 384×288 recommended 640×480 peak 1024×768	min. 1.5 mrad better 1 mrad + telephoto lens	min. 80 mK better 50 mK Best 30 mK (30mK: can be measured over several days = better return)	manual capture: min. 50 Hz	– selectable color scale – autofocus – telephoto lens – wide-angle lens
Electrical equipment measurement	8…12 µm	bolometer (photon detector also good, but expensive)	min. -0°C … 150°C better -20°C … 250°C	min. 160×120 better 320×240 recommended 384×288 or 640×480 peak 1024×768	min 2 mrad better 1.5 mrad best 1 mrad	min. 120 mK better 80 mK best 50 mK	manual capture: min. 50 Hz	– selectable color scale – autofocus – digital video camera – composite imaging – digital sound recording
Mechanical equipment measurement	8…12 µm	bolometer (photon detector for moving objects, fast processes)	min. -20°C … 250°C better -40°C … 400°C	min. 160×120 better 320×240 recommended 384×288 or 640×480 peak 1024×768	min 2 mrad better 1.5 mrad	min. 120 mK better 80 mK best 50 mK	manual capture: min. 50 Hzmoving objects: >>50 Hz	– selectable color scale – autofocus – burst capture – difference capture – digital video camera – composite imaging – digital sound recording
Medical (biological) measurements	8…12 µm	bolometer (photon detector also good, but expensive)	min. -20°C … 50°C better from -40°C (approximate upper limit)	min. 320×240 better 384×288 recommended 640×480 peak 1024×768	min. 1.5 mrad better 1 mrad	min. 50 mK better 30 mK best 10 mK	manual capture: min. 50 Hz	– selectable color scale – autofocus – burst capture – difference capture – high image homogeneity – composite imaging
Glass-related measurements	3…5 µm (8…12 µm only for glass surfaces)	photon detector	min. 100°C … 1200°C better 0 … 2000°C	min. 320×256 recommended 640×512 peak 1280×1024	min 2 mrad better 1.5 mrad	min. 120 mK better 80 mK	process-dependent (typical >>50Hz)	– selectable color scale – autofocus – burst capture – difference capture – special filters – macro lenses – microscope lenses – protective windows
Microelectronic measurements	8…12 µm (3…5 µm also good, but expensive)	bolometer (photon detector for fast thermal processes)	min. -0°C … 150°C better -20°C … 250°C	min. 320×240 better 384×288 recommended 640×480 peak 1024×768	min. 1.5 mrad recommended 1 mrad better 0.7 mrad +special lenses	120 mK better 80 mK best 50 mK	> 2 x process frequency (min. 50 Hz)	– selectable color scale – autofocus – burst capture – difference capture – macro lenses – microscope lenses – pixel-wise emissivity correction – fast thermal imaging
Metallurgical measurements	8…12 µm or 3…5 µm	bolometer or photon detector	min. 300°C … 1200°C better 0 … 2000°C	min. 160×120 better 320×240 recommended 384×288 or 640×480 peak 1024×768	min 2 mrad better 1.5 mrad	120 mK better 80 mK	manual capture: <span style=”font-size:

Closing Remarks

There is a recurring need for a universal thermal camera. When hearing that there is NONE, one can feel not only disappointment but almost outrage! The typical reaction is: "But I don't want to do anything special - just measure buildings, switch cabinets, and solar panels. Like everyone else, with a good cheap device. It doesn't even have to be accurate." Hopefully, this article has shed light on at least a few aspects throughout the preceding 21 pages, revealing that a universal (even suitable for EVERYTHING) thermal camera cannot exist. Each task imposes different technical requirements on our measuring equipment, and even the existing equipment may only be suitable for certain measurements. Therefore, those who are unsure about the specific measurement tasks they will perform with a thermal camera should not buy a device just because they have some leftover money and think they will need a thermal camera anyway! It may turn out that the acquired device is completely unsuitable for the intended task, and a different type, design, or feature set of device would be more appropriate.

Moreover, thermal imaging tasks typically do not end with the display of thermal camera images. It is necessary to correct potentially very complex radiometric measurement conditions (beyond mathematical models integrated into the thermal camera), create line-profile temperature charts, temporal temperature diagrams, or even histograms, perhaps playable thermal image videos and numerical evaluations, not to mention the visually appealing (clearly revealing even to a layman) reports. However, for this, we need appropriately "smart" and versatile PC software capabilities. It is also important to check what software support exists for the specific thermal camera.

Finally, there is only one - but decisive - question left: How much is the best measuring instrument worth?
The answer is extremely simple: As much as we understand the technology to be performed with the instrument!

And this is particularly true for thermographic tools! Thermal cameras are now so widespread that there is hardly an industry where they are not used. Their handling is comparable to that of a video camera. Yet (or perhaps because of this?), almost 99% of users have never dared to measure precise object temperatures! Simply because they are not aware that even the most advanced thermal camera does not exempt us from the necessity of understanding the technological (theoretical and practical) background of these measurement methods! Otherwise, the interpretation and necessary input of parameters for temperature calculation cannot be done! (There is no thermal camera that automatically - "on its own" - determines the object's emissivity factor!)

But there are further questions: Why are there thermal cameras with different wavelength ranges? Why are there objects whose temperature cannot be determined contactlessly? What is ambient temperature, what is its role and determination? What does the maximum measurement distance depend on? What is the smallest measurable object? Can we see inside the objects being measured? If any of these questions raise uncertainty in us, then the question arises: What is the value of the most professional thermal camera if we cannot confidently provide the measurement parameters during its application, based on which the camera calculates the temperature values?

Therefore, we must learn how and under what conditions thermographic measurements can be carried out, what parameters need to be provided for accurate temperature measurement, how to interpret the technical parameters of thermal cameras, what are the possibilities and limitations of thermography. Only with this knowledge will we have any possibility of measuring temperatures accurately! PIM Professional Industrial Measurement Technology Ltd. can help with this - in its wide range of courses, you will surely find the one that suits you, and the presenter's internationally recognized professional expertise is a guarantee that you will gain correct and immediately applicable knowledge in practice.

Rahne Eric (PIM Ltd.)
pim-kft.hu
termokamera.hu

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