Yet again I am faced with the question “How can I make a thermal imaging camera from a Webcam?”

I am often asked this, and in particular if the webcam can be converted to work as a thermal imaging camera.

The answer to this is that you cannot make a true thermal imaging camera from a webcam. Webcams operate in the visible part of the spectrum (about 0.4 to 0.7 microns), thermal imaging cameras generally operate in the LWIR region (about 8-14 microns). While a webcam can operate a little beyond the visible region, perhaps into the NIR region, and technically this is infrared, you will not really see emitted radiation due to an objects heat. Objects do not radiate enough heat in this part of the spectrum unless they are very hot (Plancks Law/ Wiens Law). Therefore what you will see if you filter the webcam is essentially reflections, and not the thermal energy emitted by an object itself. Thermal imaging detects energy emitted by an object due to its own temperature, a microbolometer is used instead of a CCD. In some cases PtSi or InSb detectors are used, but these are very expensive and unlikely to be used in a webcam. You would have to buy a true thermal imaging webcam, or convert the Flir one or C2 for use as a webcam.