Webcams (web cameras) are small cameras (usually, though not always, video cameras), whose images can be accessed using the World Wide Web, instant messaging, or a PC video conferencing application. The term webcam is also used to describe the low-resolution digital video cameras designed for such purposes, but which can also be used to record in a non-real-time fashion.
Web-accessible cameras involve a digital camera which uploads images to a web server, either continuously or at regular intervals. This may be achieved by a camera attached to a PC, or by dedicated hardware. Videoconferencing cameras typically take the form of a small camera connected directly to a PC. Analog cameras are also sometimes used (often of the sort used for closed-circuit television), connected to a video capture card and then directly or indirectly to the internet.
In addition to use for personal videoconferencing, it was quickly realized that World Wide Web users enjoyed viewing images from cameras set up by others elsewhere in the world. While the term “webcam” refers to the technology generally, the first part of the term (“web-“) is often replaced with a word describing what can be viewed with the camera, such as a netcam or streetcam. Educators can use webcams to take their students on virtual field trips.
Today there are millions of webcams that provide views into homes, offices and other buildings as well as providing panoramic views of cities and the countryside. Webcams are used to monitor traffic with TraffiCams, the weather with WeatherCams and even volcanoes with VolcanoCams. Webcam aggregators allow viewers to search for specific webcams based on geography or other criteria.