Can webcam software work with infra-red cameras?

Everybody know that infra-red (IR) cameras see in the dark, but there is a lot of uncertainty about how that works. Here are a few facts...

Firstly the answer is yes, webcam software can work with infra-red cameras. Actually, dealing with infra-red is the camera's job. The camera sends an image to the computer, and the software deals with it. Some cameras provide good or bad images, and this will affect the software's performance. In order to do any kind of image processing (motion detection, subject tracking, computer vision...) the software needs to get images that are as good as possible, and that depends on the camera and the lighting in the scene.

Infra Red Cameras
Infra-Red means that the camera's sensor goes beyond the normal human-visible color, and extend into the infra-red spectrum that our eyes cannot see. In order for this camera to be useful, the scene need to contain infra-red light. The sun is a natural provider of IR, but using the sun that defeats the idea of seeing in the dark. In the dark, we'll need a IR source, and that is usually an array of IR LEDs located around the lens of the camera.

Here is the tricky part: since our eyes cannot see infra-red, the camera needs to render the resulting image with colors that we can perceived, so usually this is in tones of gray. We loose the Red-Green-Blue in exchange for gray, which is better than black. So this is the image that the computer gets from the camera, and the software then performs motion detection in it.

Thermal Cameras
Thermal vision is another kind of infra-red imaging, but quite different. Imagine the movie The Predator, where the alien can see the temperature of bodies instead of light. Everything that produces heat also emits infra-red light, ever so slightly in the case of humans and animals, intensely in the case of fire. This camera's sensor is different from a normal camera's, it is set for a wavelenght of light further away in the infra-red spectrum. Thermal cameras, and their sensors are much more expensive than normal cameras, and are not widely available. One interesting aspect is that since the thermal camera relies on the infra-red light emitted by things, it does not require a lighting source.

Most thermal cameras will output gray images, where heat is represented with lighter scales of gray. The output image can be a representation of blue/yellow/red, where red represents the warmest areas of the image, but this is just aesthetics.

Connecting an IR camera to the computer
Not all infra-red and thermal cameras can be connected to a computer directly. Most only output an analog signal (using BNC or RCA connection), in which case a video capture device is necessary to interface the camera to the computer. Cheap USB video capture devices can be purchased in most computer stores.

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