The term "webcam" (a clipped compound) may also be used in its original sense of a video camera connected to the Web continuously for an indefinite time, rather than for a particular session, generally supplying a view for anyone who visits its web page over the Internet.Some of them, for example, those used as online traffic cameras, are expensive, rugged professional video cameras.Webcam features and performance can vary by program, computer operating system, and also by the computer's processor capabilities.Video calling support has also been added to several popular instant messaging programs. Software is available to allow PC-connected cameras to watch for movement and sound, a computer e-mailed images of the burglar during the theft of the computer, enabling the owner to give police a clear picture of the burglar's face even after the computer had been stolen.
For example, the position of a single light source can be tracked and used to emulate a mouse pointer, a head-mounted light would enable hands-free computing and would greatly improve computer accessibility.
Webcams can be used to take video clips and still pictures.
Various software tools in wide use can be employed for this, such as Pic Master (for use with Windows operating systems), Photo Booth (Mac), or Cheese (with Unix systems).
The lenses of the cameras are removed and then these are attached to telescopes to record images, video, still, or both.
In newer techniques, videos of very faint objects are taken for a couple of seconds and then all the frames of the video are "stacked" together to obtain a still image of respectable contrast.
Researchers claim that this method is accurate to ±5 bpm.