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 CamerasInfra-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 CamerasThermal 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 computerNot 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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