With the increasing popularity of infrared thermal temperature cameras in various industries, more and more enterprises are realizing the benefits of adding thermal imaging sensors to their projects. Here are some things you need to understand before adding a thermal temperature camera to your work.
Night vision and thermal images compared: Thermal imaging is completely unaffected by visible light. Compared with visible light cameras, the resolution of infrared thermal temperature camera module seems to be lower, but there is a reason for this. Infrared thermal temperature cameras use detector elements that are much larger than those in visible light cameras. Visible cameras have pixels only 1-2μm, while the detector pixels in infrared thermal temperature cameras are 12-17μm each. This is because the thermal detector needs to sense energy with a wavelength much larger than visible light, which requires each detector pixel to be much larger. Therefore, compared to visible light cameras with the same mechanical dimensions, infrared thermal temperature cameras usually have lower resolution.
First, ask yourself, what kind of infrared image do you need? How far do you need to see? And how much detail do you need in the image? If you only need to detect an object, one pixel is enough. If you need to recognize objects (such as people, animals or vehicles), you need higher resolution. You may even need more pixels to identify the details of the object (such as if it is an armed person, a dog instead of a deer, or a truck instead of a car). Resolution determines the details that the thermal temperature camera can detect. Infrared thermal temperature cameras range from low-cost imaging devices to high-performance infrared thermal temperature cameras used for search and rescue.
The sensitivity of an infrared thermal temperature camera module is specified as noise equivalent temperature difference (NETD). NETD is a signal-to-noise ratio indicator that tells you the temperature difference required to produce a signal equivalent to the time noise of the infrared thermal temperature camera and the minimum temperature difference that the infrared thermal temperature camera can distinguish. For applications that require detecting subtle temperature differences and fine details, a lower NETD is very important. NETD is usually expressed in millikelvin, and the smaller the number, the better the performance.
Infrared thermal temperature cameras are usually sensitive to only one of two bands: mid-wave infrared (MWIR) at 3-5μm or long-wave infrared (LWIR) at 8-14μm. Although there are exceptions, most MWIR infrared thermal temperature camera modules require vehicular low-temperature coolers to cool the infrared detectors to about 77 Kelvin to generate images. Cooling-type infrared thermal temperature cameras are more sensitive than the uncooled thermal imager, but coolers increase size, weight, complexity, and cost, and require regular maintenance.
All thermal temperature camera modules can provide images of the relative thermal energy within their field of view, but some infrared thermal temperature cameras go further and provide calibration, non-contact temperature measurement, and this process is called radiation measurement. To do this, infrared thermal temperature cameras need to compensate for other radiation sources (reflection, lens material), atmospheric effects (humidity, weather conditions, and distance from the target), and material characteristics of the observed object (especially emissivity). Once these elements are known, the amount of radiation received by the infrared thermography camera can be converted into temperature values, with an accuracy of approximately ±2℃.
