The highest and lowest temperature required to be measured defines the temperature range required by the thermal camera. The range is the set of temperatures that the camera is capable of measuring.
It is very important when selecting a infrared camera to first know the range of temperatures that we are going to get in our application and that we need to measure.
The spectral range is the range of wavelengths that the thermal camera sensor is able to detect.
The spectral range is an important factor to consider when selecting a thermal camera and will depend on the target material and its emissivity. Emissivity is the parameter that determines the proportion of thermal radiation emitted by a surface or object due to its temperature.
To minimize errors and increase the accuracy of the measurement we have to choose the thermal camera with the shortest wavelength that can measure the temperature range of our application.
For example, if we want to measure 600°C and we do not need to measure values less than 450°C, then we will choose a 1 micron camera (NIR camera). Although we can use an LWIR (7 to 14 microns), the temperature measurement will be more accurate with the shorter wavelength.
According to the temperature ranges we want to measure, the most commonly used industrial thermal cameras are of the following:
The thermal sensitivity (Noise Equivalent Temperature Difference, NETD) is equivalent to the smallest differential in temperature that is able to measure the infrared camera without being attributed to its own noise. Thermal sensitivity is equivalent to the thermal resolution of the camera (it is the minimum measurement value between two consecutive temperatures).
The more sensitive the detector (lower NETD), the finer the temperature details the thermal camera is able to display.
Conventional cameras have a NETD between 80mK and 100mK, while the cameras with the highest sensitivity can have 40mK at competitive prices or at 20mK or even 10mK for those with the highest performance (usually cooled and with high cost).
If the objectives to be measured have large temperature differences, a camera with a low NETD is probably not necessary.
The resolution of the thermal camera sensor, also called detector, determines the quality of the rendered image. The resolution indicates the number of pixels in the detector. More pixels means higher resolution.
The higher the resolution of the detector, the sharper and more accurate each individual point in the image will be, allowing for more precise measurements and better decisions.
Higher resolution infrared cameras can measure smaller targets at a greater distance and create sharper thermal images for more accurate and reliable measurements.
The most widely used resolutions in the industry are 80×80, 160×120, 382×288 and 640×480 pixels in LWIR and 764×480 pixels in NIR.
The field of view (FOV) is determined by the thermal camera lens and refers to the extent of the scene that the camera can capture. The greater the field of view, the greater the area or space that can be captured with the thermal camera.
IRLENS are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.
Some cameras are available with multiple lenses for different types of applications. A camera that allows you to change the lens increases its versatility.
Knowing the distance at which the camera can be installed and the size of the smallest detail that we want to measure in the scene, allow us to identify the ideal optics for our application.
The lens is an indispensable part of the infrared thermal imager. Its function is to converge the infrared radiation of the target on the infrared detector, and through photoelectric conversion and image processing, it finally forms an image with good contrast. The quality of the infrared lens largely determines the performance of the infrared camera.
1. Band
The infrared lens should be specially designed according to its working band to optimize its performance. The infrared materials used in the infrared lenses of different bands are also different.
2. Vignetting
Generally speaking, infrared lenses do not allow vignetting. For the lens used in the infrared cooling detector, if the lens has vignetting, it cannot meet the 100% cold diaphragm efficiency design principle, and stray radiation will affect the performance of the infrared thermal imager.
3. Focal length and field of view
An infrared lens is usually identified by its focal length. As the focal length increases, the field of view of the lens narrows. Conversely, as the focal length decreases, the field of view becomes wider.
Infrared lenses can generally be divided into single-field lenses, multi-field lenses, and continuous zoom lenses. Since the infrared continuous zoom lens can realize target search and continuous tracking of targets at different distances, it has been widely used in many fields.
4. F number
The F number of the infrared lens determines how much the target radiant energy enters the infrared thermal imager. The smaller the F number, the larger the size of the infrared lens under the same focal length.
5. Transmittance
Most infrared materials have a high refractive index, and the lens in the infrared lens needs to be coated with a high-efficiency antireflection coating to increase the transmittance of the infrared lens. As the number of lenses in the lens increases, the transmittance of the lens gradually decreases.
6. No heating
Since the refractive index of infrared materials varies greatly with temperature, when the ambient temperature changes, the infrared lens will produce a corresponding defocus. The infrared lens also adopts two methods of active and passive to achieve athermalization to ensure that the focal position of the lens does not move when the temperature changes.
Want more information on MWIR Lens for Cooled Camera? Feel free to contact us.