How do I pick the right thermal imager for my integrated product?
Selecting the right thermal camera will be largely dependent upon what you want the camera to do, and a number of factors play into this determination.
What resolution and lens do I need?
The answer to this question will be determined by what you need to image, how far away you need to see it, and the level of detail you need in the images. There is a range of thermal cameras from lower-cost imagers that go into smart phones to highperformance cameras that are used for critical, life-saving missions. FLIR cameras like Boson are available in qVGA (320x256) resolution, and VGA (640x512) resolution, and have horizontal fields of view (FOV) ranging from 4° to 92°. Lower-cost solutions like Lepton are available in lower resolutions like 80x60 and 160x120. The camera’s resolution will relate directly to image detail and potential detection range. If you just need to detect an object, a single pixel may be enough to do the job. If you need to recognize what an object is, say, a person, an animal, or a vehicle you’ll need a larger group of pixels. Even more pixels still may be necessary to identify the nature of an object, such as if it’s an armed person, a dog rather than a deer, or a truck instead of a car. Dividing the width of the scene in that FOV by the horizontal number of pixels will tell you the smallest feature that can be detected at that distance. You can also use a specification called the “instantaneous field of view” (iFOV) to get the angular size of a single pixel and calculate its size at a given range as well.
What sensitivity do I need?
A camera’s sensitivity is specified as the Noise Equivalent Differential Temperature (NEDT). It’s a signal-to-noise metric that tells you the temperature difference required to produce a signal equal to the camera’s temporal noise, and – by extension – the minimum temperature difference the camera can resolve. NEDT is usually expressed in milliKelvin (mK), with lower numbers indicating superior performance than higher numbers. The FLIR Boson has industry-leading sensitivity of less than 50 mK. Once you’ve thought these factors through, contact our Applications Engineering team; they’ll help you explore your options a little deeper and get the solution you need.