webcam

A typical webcam

Webcam on monitor

Webcams are video capture devices connected to computers or computer networks, often using a USB port or, if they connect to networks, via ethernet or Wi-Fi.

Their most popular use is for video telephony, permitting a computer to act as a videophone or video conferencing station. Other popular uses, which include the recording of video files or even still-images, are accessible via numerous software programs, applications and devices.

They are well known for their low manufacturing costs and flexibility.

History

First employed in 1991, a webcam called the CoffeeCam, was pointed at the Trojan room coffee pot in the computer science department of Cambridge University. The camera was finally switched off on August 22, 2001. The final image captured by the camera can still be viewed at its homepage.^[1] The coffee machine was repaired for free by Krups.^[2]

The oldest webcam, as the technology came to be known, still operating is FogCam at San Francisco State University, which has been running continuously since 1994^[3].

One of the most widely reported-on webcam sites was JenniCam, started in 1996, which allowed Internet users to constantly observe the life of its namesake, somewhat like reality TV series Big Brother, launched three years later^[4]. More recently, the website Justin.tv has shown a continuous video and audio stream from a mobile camera mounted on the head of the site's star.

Recently,^[when?] Apple and other computer hardware manufactures began building webcams directly into laptop and desktop screens, thus eliminating the need to use an external USB or Firewire webcam.

Video calling and conferencing

As webcam capabilities have been added to instant messaging, text chat services such as AOL Instant Messenger, one-to-one live video communication over the Internet has now reached millions of mainstream PC users worldwide. Improved video quality has helped webcams encroach on traditional video conferencing systems. New features such as automatic lighting controls, real-time enhancements (retouching, wrinkle smoothing and vertical stretch), automatic face tracking and autofocus assist users by providing substantial ease-of-use, further increasing the popularity of webcams.

Webcam features and performance can vary by program, computer operating system and also by the computer's processor capabilities. For example, 'high-quality video' is principally available to users of certain Logitech webcams if their computers have dual-core processors meeting certain specifications.

Video calling support has been included in programs as Yahoo Messenger, AOL Instant Messenger (AIM), Windows Live Messenger, Skype, iChat, Paltalk (now PaltalkScene), Ekiga , Stickam,Tokbox, Camfrog, Gmail and Meetcam.

Some online video broadcasting sites have taken advantage of this technology to create Internet television programs centered around two (or more) people "diavlogging" with each other from different locations. Among others, BloggingHeads.tv use this technology to enable conversations between prominent journalists, scientists, bloggers, and philosophers.

Video security

Webcams are also employed for security purposes. Software is available to allow PC-connected cameras to watch for movement and sound, recording both when they are detected; these recordings can then be saved to the computer, e-mailed or uploaded to the Internet. In one well-publicised case,^[5] a computer e-mailed out images as the burglar stole it, allowing the owner to give police a clear picture of the burglar's face even after the computer had been stolen.

Input control device

Special software can use the video stream from a webcam to assist or enhance a user's control of applications and games. Video features, including faces, shapes, models and colors can be observed and tracked to produce a corresponding form of control. For example, the position of a single light source can be tracked and used to emulate a mouse pointer, a head mounted light would allow hands-free computing and would greatly improve computer accessibility. This can also be applied to games, providing additional control, improved interactivity and immersiveness.

FreeTrack is a free webcam motion tracking application for Microsoft Windows that can track a special head mounted model in up to six degrees of freedom and output data to mouse, keyboard, joystick and FreeTrack supported games.

The EyeToy for the PlayStation 2 (The updated PlayStation 3 equivalent is the PlayStation Eye) and similarly the Xbox Live Vision Camera for the Xbox 360 and Xbox Live are color digital cameras that have been used as control input devices by some games.

Small webcam-based PC games are available as either standalone executables or inside web browser windows using Adobe Flash.

Aggregators

Due to the increasing number of webcams throughout the world, aggregator websites have arisen, allowing users to find live video streams based on location or other criteria. Aggregators provide collections of thousands of live video streams or up-to-date still pictures.

Technology

Webcams typically include a lens, an image sensor, and supporting circuitry.

Webcams typically include a lens, an image sensor, and some support electronics. Various lenses are available, the most common being a plastic lens that can be screwed in and out to set the camera's focus. Fixed focus lenses, which have no provision for adjustment, are also available. As a camera system's depth of field is greater for small imager formats and is greater for lenses with a large f/number (small aperture), the systems used in webcams have sufficiently large depth of field that the use of a fixed focus lens does not impact image sharpness much. Image sensors can be CMOS or CCD, the former being dominant for low-cost cameras, but CCD cameras do not necessarily outperform CMOS-based cameras in the low cost price range. Most consumer webcams are capable of providing VGA-resolution video at a frame rate of 30 frames per second. Many newer devices can produce video in multi-megapixel resolutions, and a few can run at high frame rates such as the PlayStation Eye, which can produce 320×240 video at 120 frames per second.

Support electronics are present to read the image from the sensor and transmit it to the host computer. The camera pictured to the right, for example, uses a Sonix SN9C101 to transmit its image over USB. Some cameras - such as mobile phone cameras - use a CMOS sensor with supporting electronics "on die", i.e. the sensor and the support electronics are built on a single silicon chip to save space and manufacturing costs. Most webcams feature built-in microphones to make video calling and conferencing more convenient.

The USB video device class (UVC) specification allows for interconnectivity of webcams to computers even without proprietary drivers installed. Microsoft Windows Vista, Linux^[6] and Mac OS X 10.4 & 10.5 have UVC drivers built in and do not require extra drivers, although they are often installed in order to add additional features.

Privacy

Some 'Trojan horse' programs can allow malicious hackers to activate a computer's camera without the user's knowledge, providing hackers with a live video feed from the unfortunate user's camera.^{[citation needed]} Cameras such as Apple's older external iSight cameras include lens covers to thwart this. Most other webcams have a built-in LED that lights up whenever the camera is active (such as Apple's newer internal iSight), although the malicious nature of a Trojan horse could have the LED programmed to be disabled even when the webcam is online.^{[citation needed]}

In mid-January 2005 some search engine queries were published in an on-line forum^[7] which allow anyone to find thousands of Panasonic- and Axis-made high-end web cameras, provided that they have a web-based interface for remote viewing. Many such cameras are running on default configuration, which does not require any password login or IP address verification, making them visible to anyone.

Effects on modern society

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Positive uses

Video chat is a good example of positive use, since it allows for cheap real-time communication from anywhere in the world. Webcasting is generally also a positive side of webcams, although terrorist groups also use it to spread their opinions. Webcasting has spun up a global community, based primarily on amateur video production. However, news websites like the BBC also produce professional live news videos.^[8] YouTube is another popular example of amateur produced video material.

Negative uses

Internet privacy is the biggest concern of webcams. Children and teens under the legal age of consent have easy access to video broadcasting hardware and software, worrying their parents. Adult webcam related material is also a large portion of the webcam related sites on the internet and can be easily accessed through search engines if no parental control is enforced. On 2007-03-23, a man named Kevin Whitrick committed cyber suicide live on the internet in front of viewers in a chat room website.^[9]

See also

• List of digital camera brands
• Video camera
• Videophone
• Videoconferencing
• List of video telecommunication services and product brands

References

Wikimedia Commons has media related to: Webcams