Since time immemorial, human beings have devised various ways to enable them to see in the dark. First, there was the invention of fire, then flashlights, and recently, night vision goggles. A relative newcomer to the general public is the thermal imaging camera. For a long time, thermal imaging technology was extremely expensive and only applied in the military and big corporations. However, due to the advancement of technology, prices are coming down, and thermal imaging devices are becoming more accessible to the general public.
What is a thermal imaging camera? How does it work? How is it used in hunting and other wildlife applications?
What is thermal imaging?
Thermal imaging technology, also known as thermography, is a great way to see in the dark. These cameras work by detecting infrared radiation emitted by objects and capture the variation in temperatures in different shades of colors.
On the thermal image, warm regions stand out in contrast to the cooler backgrounds. Most people don’t know that a thermal imaging camera cannot see through a window. This is because the window itself also radiates some form of radiation.
For a long time, thermal imaging cameras have been widely used to detect humans during military or surveillance operations at night. Also, firefighters and other search and rescue responders use these cameras to search for people trapped behind debris or smoke. All in all, thermal imaging technology is an invasive and safe way to detect infrared radiation, making it an effective tool for tracking warm-blooded animals.
How do thermal imagers work?
Thermal imaging cameras detect the heat radiated by objects in the long-wave infrared range of between 8µm to 14µm on the electromagnetic spectrum. This heat is not visible with the human eye. The operation of thermal imagining cameras contrasts that of normal digital cameras which detect light in the range of 0.40µm -0.75µm, also known as the visible spectrum.
The best part of thermal imaging cameras is that they can detect objects with or without visible light. This is because all objects with a temperature above absolute zero emit some form of infrared radiation. Actually, most thermal imaging cameras can detect objects warmer than -50OC.
Are thermal imaging cameras and night vision the same?
Even though both thermal imaging and night vision devices are used to increase visibility in low light conditions, they are very different. Night vision devices work by amplifying light while thermal imaging devices work by detecting longer wavelength infrared radiations.
Thermal imaging devices require acute sensors that enable them to detect long-wave infrared radiations. This is the reason why these devices are expensive than night vision devices. However, as thermal imaging technology continues to advance, prices are dropping.
Even though night vision devices improve visibility in the dark by amplifying the amount of light in the image, thermal imaging devices have the added advantage of producing high contrast images. This makes it easier to identify animals even in hideouts.
Do thermal imaging cameras work only at night?
Although thermal imaging cameras are popularly known for night vision, they can also be used during the day. The ability to detect heat and high contrast enables the user to see outlines of even animals that camouflage. Also, thermal imaging cameras can be used to distinguish animals or people in smoky or foggy conditions that limit visibility.
Thermal imaging technology has proven helpful in combating wild animals that inhabit crop fields, which negatively affect agricultural operations. For instance, farmers in the southeastern parts of the US, use thermal imaging devices to protect their farmlands from wild hogs.
Do thermal imaging cameras work only on land? Can thermal imaging cameras see in the water?
Thermal imaging cameras do not work underwater. Even high-end devices will produce close-to-none useful images. As mentioned earlier, thermal imaging devices work by detecting the infrared radiation emitted by objects. Water acts as a blocker that hinders the passing of infrared radiations that thermal imaging devices require to work adequately.
Just like the human sight cannot see through an opaque surface, it is exactly the same way thermal imaging devices cannot see through the water. Infrared radiations that thermal imaging cameras detect do not pass through water as easily as they do through the air.
Furthermore, water can also significantly affect the performance of thermal imaging devices. In an open space, objects emit heat much faster than when in water. As a result, thermal imaging devices will need much more performance power, which has not been developed yet, to detect objects in water successfully. However, as technology continues to advance rapidly, thermal imaging devices will soon be used for underwater operations.
The use of thermal imaging cameras in relation to wildlife
Thermal imaging technology is used in a wide range of applications in ecology and zoology. These are some of the common applications of thermal imaging cameras.
- Wildlife documentaries
Thermal imaging cameras are used for filming the nocturnal behavior of animals. Filmmakers have been able to capture rare footage of animals at night. Even during the day, thermal imaging cameras help filmmakers to spot animals that camouflage in shrub vegetations.
- Veterinary medicine
Wildlife veterinaries are increasing relying on thermal imaging devices in detecting the psychological changes in animals. This has enabled them to diagnose critical conditions, such as arthritis in elephants.
- Studying animal behavior
Animal researchers use thermal imaging technology for thermoregulation. For example, it is this technology that enabled researchers to ascertain that an Asian elephant cools their bodies through the trunk and not through the ears like other elephants.
Night hunting has become very popular in the recent past. To see in the dark, hunters require a visual aid. Even though a flashlight can provide sufficient illumination, they attract attention. Night vision devices can also be used. However, some animals hide to avoid detection. The only thing they can’t hide is their heat radiation, which is detected by thermal imaging devices. Therefore, thermal imaging cameras are an unbeatable solution for hunters and wildlife conservationists.