One of the most interesting aspects of our industry is seeing how aerial survey work touches so many industries, from agriculture and forestry to environmental monitoring and search and rescue operations.
Our clients often have many different types of sensor assets, and one of the most specialized are thermal camera sensors.
In this article, we'll delve into the world of thermal camera sensors for surveying, exploring what they are, the different types available, how they are used, and the advantages and potential pitfalls of using them.
Thermal imaging, also known as infrared imaging, is a technology that allows us to capture and visualize the heat radiating from an object or scene.
Unlike traditional cameras, which capture visible light, thermal cameras work with infrared radiation, enabling them to "see" heat variations. This feature makes them invaluable tools in diverse survey applications.
Aerial surveyors employ thermal camera sensors in a variety of ways, depending on the goals and requirements of their projects. Here are some common applications and use cases for thermal camera sensors in aerial surveying:
One of our clients, Aaron Schepers, President of Cornerstone Mapping, Inc shared his experience with using thermal camera sensors:
“Thermal imaging requires an excellent working knowledge of thermal remote sensing principles. The mapping application determines the time of year for the flight and whether data collection should occur during the day or nighttime.”
Aaron shared two images from his work that illustrate some real-world application of thermal imaging.
The image below is from a state penitentiary shows how Cornerstone Mapping used a thermal camera sensor to map underground steam lines to identify leaks. Universities and large campuses also often use steam to heat their facilities.
The next image shows how thermal imaging was used to map the location of groundwater inflows into streams and rivers in a project for the USGS.
Cornerstone Mapping flew hundreds of miles of streams in the Nebraska Sandhills to locate groundwater inflows that are not visually identifiable.
Groundwater maintains a yearly average temperature of around 58 degrees F, while the soil is near freezing during the winter. As you can see from the image, thermal contrast readily identifies the locations of groundwater inflows.
Cameras made especially to detect infrared wavelengths include SWIR (short-wave infrared), MWIR (Mid-Wave Infrared), or LWIR (Long-Wave Infrared) cameras.
These terms relate to the specific portions of the electromagnetic spectrum these cameras are designed to capture.
The differences between SWIR, MWIR, and LWIR cameras revolve around what they’re made of and how they get used.
SWIR cameras operate in the short-wave infrared spectrum, which typically covers wavelengths between 1,000 nanometers (1 micron) and 2,500 nanometers (2.5 microns). These wavelengths are beyond what the human eye can perceive (the visible spectrum), and they extend into the infrared region. SWIR capture light reflected or absorbed by an object.
SWIR cameras are useful for aerial survey because they can penetrate through fog, smoke, and smog pollution, making SWIR cameras ideal for IR imaging through adverse conditions.
SWIR cameras are also often used in night vision and security applications due to their ability to capture infrared radiation, even in low light conditions.
MWIR cameras are engineered to capture infrared radiation in the mid-wave portion of the spectrum, typically ranging from approximately 3 to 5 microns in wavelength. MWIR cameras detect heat emitted by an object.
Unlike SWIR cameras, they don’t work well through dust, smoke, air pollution, or fog. However, they are very good at detecting gas leaks that the naked eye can’t see, making these cameras suitable for applications like industrial inspections.
MWIR sensors are also less susceptible to atmospheric conditions. This is critical for airborne survey operations. They can operate in various climates, including those with high humidity, making them particularly well-suited to marine and coastal environments.
LWIR cameras are designed to capture thermal radiation in the long-wave portion of the infrared spectrum, typically covering wavelengths from about 8 to 14 microns. Like MWIR, LWIR cameras detect heat emitted by an object.
LWIR cameras are highly effective at thermal imaging in outdoor environments and building inspections due to their capability to capture the heat emitted by objects and provide temperature-related information.
Aerial surveyors have several options when it comes to thermal sensors. Each type of sensor has its own set of advantages and limitations, making it essential for professionals to choose the one that best suits their specific needs.
Here are some common types of thermal sensors:
In addition to the sensor type, the choice of lens is a crucial factor in aerial surveying with thermal cameras.
Different lenses are suited to different surveying needs, and aerial surveyors must carefully select the right lens for their specific project. Here are some common types of lenses used in aerial surveys:
Aerial surveyors have several compelling reasons for choosing thermal camera sensors in their work:
While thermal cameras offer numerous benefits, there are also some potential pitfalls to be aware of:
From wildlife monitoring and search and rescue missions to agriculture, environmental monitoring, and beyond, thermal camera sensors have become indispensable tools. How do you use thermal cameras in your business?
You can see all of our cameras… RGB, NIR, Achro, and more at AERIALSURVEY.com. Let us know what questions you have. We’d love to hear from you.