A Thermal Camera is a camera that creates an image using infrared radiation. It differs from a normal camera that uses visible light to form an image. While traditional cameras use a nanometer range of 400-700 of visible light, infrared cameras are sensitive to wavelengths of 1000 to 14,000 nm.
Read on to find out more about Thermal Cameras and how they operate.
How Do Thermal Cameras Work?
A regular camera works like the human eye. When visible light energy bounces off the camera, it detects the reflected light and turns it into an image.
An infrared camera makes pictures from heat instead of light. Heat and light are both parts of the electromagnetic spectrum, but a camera that detects visible light won’t see thermal energy and vice versa. Thermal cameras capture infrared energy and use the data to create images through digital or analog outputs.
What are the Components of a Thermal Camera?
A thermal camera consists of a lens, a thermal sensor, processing electronics, and mechanical housing. The lens focuses infrared energy onto the sensor. The sensor comes in various pixel configurations that range from 80 x 60 to 1280 x 1024 and can even be higher. This is the resolution of the camera.
Resolutions are low as compared to traditional cameras due to the fact that thermal cameras need to transform larger wavelengths. This means the sensor element must be larger which results in a lower resolution.
What Can Thermal Cameras Detect?
Thermal cameras sense heat which can be very precisely measured. For example, a FLIR camera can detect differences in heat as small as .01 degree Celsius and represents them with different color patterns.
Everything in the world gives off heat, even ice. The hotter the item is, the more thermal energy it will release.
The energy that’s emitted is called a heat signature. When two objects next to each other have slightly different heat signatures, they will show up clearly to the thermal sensor regardless of lighting conditions. Therefore, thermal cameras can pick up images in complete darkness.
What Should I Look for in a Thermal Camera?
There are several features to look for when shopping for a thermal camera. These include the following:
Range
Some cameras have multiple ranges to accurately measure a wider span of temperatures.
Field of View
The Field of View is determined by the camera lens and the portion of a scene the camera will see at any given moment.
IR Resolution
This refers to how many pixels the camera has. A higher resolution camera will pick up more details than a camera with fewer pixels.
Thermal Sensitivity
The thermal sensitivity or Noise Equivalent Temperature Difference (NETD) refers to the small differences in temperature the camera will see. The lower the number, the better the sensitivity and the more contrast it will pick up.
Focus
Thermal cameras may be fixed focus, automatic focus, or manual focus. A fixed focus will stay constant, a manual focus requires adjustment, and an automatic focus will adjust automatically. Choose the one that’s best suited to your needs.
Spectral Range
The spectral range refers to the range of wavelengths the camera can detect. Cameras with shorter ranges are ideal for gas detection while longer-range cameras are best for other applications including electrical inspections and firefighting.
What are Thermal Cameras Used For?
Thermal cameras were originally used in surveillance and military operations but today they are used in a wide range of applications including building inspections, firefighting, vehicle inspections, and scientific research purposes. They provide a neon effect that is absolutely stunning in the world of art.
A thermal camera is not your average camera, and most photographers may never have a need for them, but it’s interesting to find out how their functions differ from traditional cameras. Will you be integrating them into your shooting needs?
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