Thermal cameras are great if you want to get an idea of what’s hot and what’s not. If you want to use a thermal camera for certain machine vision tasks, however, you generally need to perform a geometry adjustment to understand what the camera is seeing and correct for lens distortion. (Henry Zhang) shared various methods to do just that.
To calibrate a thermal camera, you first need a thermal pattern. This is like a typical test image for a camera or monitor, but with temperatures instead of colors. (Henry) explains several methods to do this. One involves using a grid of nichrome wires to create a thermal pattern for calibration purposes. Another uses discs of cold aluminum embedded in foam board. Even a simple checkerboard can work, with the black spaces warming more from ambient sunlight than their neighboring white spots. (Henry) then explains the mathematical techniques used for calibration based on these patterns.
It is a useful introduction to the subject if you are working with thermal imaging systems. We’ve looked at some other interesting machine vision topics before. If you have any great thermal imaging tips, don’t hesitate to contact us!