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Animated set of x-ray images of a webcam. Images acquired using an industrial computed tomograph.

Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera for the World Wide Web gave the webcam its name. Other popular uses include security surveillance and computer vision and there are also uses on sites like video broadcasting services and for recording social videos .

First developed in 1991, a webcam was pointed at the Trojan Room coffee pot in the Cambridge University Computer Science Department. The camera was finally switched off on August 22, 2001. The final image captured by the camera can still be viewed at its homepage. [ 2 ] [ 3 ] The oldest webcam still operating is FogCam at San Francisco State University. which has been running continuously since 1994. [ 4 ]

The first known commercial webcam, the QuickCam. entered the marketplace in 1994, created by the U.S. computer hardware and software company Connectix. which later sold its product line to another U.S. company, Logitech. in 1998. QuickCam was originally the design of Jon Garber, who wanted to call it the 'Mac-camera', but was vetoed by Connectix's marketing department which saw the possibility of it one day becoming a cross-platform product. It was to become Connectix's first Microsoft Windows product 14 months later when QuickCam for Windows was launched in October 1995. The Macintosh QuickCam had shipped earlier in August 1994, and could only provide 320 x 240 pixel resolution with a grayscale colour depth of 16 shades at 60 frames per second, which would drop down to 15 frames per second if it was switched to a less basic 256 shades of gray (8-bit). [ 5 ]

The QuickCam had earlier started as a graduate degree research project in the early 1990's between various California and East Coast universities, and was originally designed with an RS-232 serial port connector color CCD camera. Both the Apple and Windows software versions were sponsored by DARPA and the U.S. Department of Veterans Affairs. The Windows software version was compiled under both MS Visual Studios and Borland C/C++ compilers for both Windows 3.11 and Windows 95. Videoconferencing via computers already existed, and at the time client-server based videoconferencing software such as CU-SeeMe had started to become popular.

The initial QuickCam model was available only for the Apple Macintosh, connecting to it via its serial port. and was sold at a cost of $100. In 2010, Time Magazine designated QuickCam as one of the top computer devices of all time. [ 6 ]

One of the most widely reported-on webcam sites was JenniCam. created in 1996, which allowed Internet users to observe the life of its namesake constantly, in the same vein as the reality TV series Big Brother . launched four years later. [ 7 ] 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. Other cameras are mounted overlooking bridges, public squares, and other public places, their output made available on a public web page in accordance with the original concept of a "webcam". Aggregator websites have also been created, providing thousands of live video streams or up-to-date still pictures, allowing users to find live video streams based on location or other criteria.

Around the turn of the 21st century, computer hardware manufacturers began building webcams directly into laptop and desktop screens, thus eliminating the need to use an external USB or Firewire camera. Gradually webcams came to be used more for telecommunication, or videotelephony, between two people, or among a few people, than for offering a view on a Web page to an unknown public.

The term 'webcam' 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 .

For less than $100 US (retail), Minoru makes a 3D webcam which produces videos and photos in 3D Anaglyph image with a resolution up to 1280x480 pixels. Both sender and receiver of the images must use 3D glasses to see the effect of three dimensional image. [ 8 ]

Childcare webcams cater to a growing demand for improved security, communications, and increased service value in daycare facilities across the country. No longer are webcams just a trend; they are quickly becoming an industry standard. According to researchers and industry leaders, as many as 100 childcare facilities add Internet viewing systems each month and that the total number of centers with some form of Internet monitoring runs into several thousands. In the United States, services such as Peanut Butter and Jelly TV have been offering premier webcasting systems to centers nationwide for many years.

As webcam capabilities have been added to instant messaging. text chat services such as AOL Instant Messenger. and VoIP services such as Skype. 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 also been added to several popular instant messaging programs.

Webcams are also used as security cameras. Software is available to allow PC-connected cameras to watch for movement and sound, [ 9 ] 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, [ 10 ] a computer e-mailed out images as the burglar who stole it, allowing the owner to give police a clear picture of the burglar's face even after the computer had been stolen.

Recently webcam privacy software has been introduced by such companies such as Stop Being Watched. The software exposes access to a webcam and prompts the user to allow or deny access by showing what program is trying to access the webcam. Allowing the user to accept a trusted program the user recognizes or terminate the attempt immediately. Other companies on the market manufacture and sell sliding lens covers that allow users to retrofit the computer and close access to the camera lens.

Webcams can be used to take video clips and still pictures. Various software tools in wide use can be employed for this, such as PicMaster (for use with Windows operating systems), Photo Booth (Mac), or Cheese (with Unix systems).

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 By removing the IR filter of the webcam, IR LEDs can be used, which has the advantage of being invisible to the naked eye, removing a distraction from the user. TrackIR is a commercial version of this technology.

The EyeToy for the PlayStation 2 (The updated PlayStation 3 equivalent is the PlayStation Eye ) and similarly the Xbox Live Vision Camera and the Kinect AKA 'Project Natal' 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 .

Webcams typically include a lens (shown at top), an image sensor (shown bottom), and supporting circuitry.

Webcams typically include a lens, an image sensor. and some support electronics, and may also include a microphone for sound. Various lenses are available, the most common in consumer-grade webcams 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 image formats and is greater for lenses with a large f-number (small aperture), the systems used in webcams have a sufficiently large depth of field that the use of a fixed focus lens does not impact image sharpness to a great extent.

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 videoconferencing more convenient.

The USB video device class (UVC) specification allows for interconnectivity of webcams to computers even without proprietary drivers installed. Microsoft Windows XP SP2, Linux [ 11 ] and Mac OS X (since October 2005) have UVC drivers built in and do not require extra drivers, although they are often installed in order to add additional features.

Many users do not wish the continuous exposure for which webcams were originally intended, but rather prefer privacy. Such privacy is lost when Trojan horse programs allow malicious hackers to activate the webcam without the user's knowledge, providing the hackers with a live video and audio feed. [ citation needed ] Cameras such as Apple's older external iSight cameras include lens covers to thwart this. Some webcams have built-in hardwired LED indicators that light up whenever the camera is active. It is not clear whether these indicators can be circumvented when webcams are surreptitiously activated without the user's knowledge or intent, via spyware.

In mid-January 2005, some search engine queries were published in an on-line forum [ 12 ] 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.

Some laptop computers have built in webcams which present both privacy and security issues, as such cameras cannot normally be physically disabled if hijacked by a Trojan Horse program or other similar spyware programs. In the 2010 Robbins v. Lower Merion School District "WebcamGate" case, plaintiffs charged that two suburban Philadelphia high schools secretly spied on students—by surreptitiously remotely activating iSight webcams embedded in school-issued MacBook laptops the students were using at home—and thereby infringed on their privacy rights. School authorities admitted to secretly snapping over 66,000 photographs, including shots of students in the privacy of their bedrooms, including some with teenagers in various state of undress. [ 13 ] [ 14 ] The school board involved quickly disabled their laptop spyware program after parents filed lawsuits against the board and various individuals. [ 15 ] [ 16 ]

Webcams allow for inexpensive, real-time video chat and webcasting, in both amateur and professional pursuits. They are frequently used in online dating and for online personal services offered mainly by women when Camgirling. YouTube is a popular website hosting many videos made using webcams. News websites such as the BBC can also produce professional live news videos. [ 17 ]

Webcams can also encourage telecommuting. where people can work from home utilizing the Internet, rather than having to travel to their office.

Webcam use can also have negative consequences. On March 23, 2007, a man named Kevin Whitrick committed suicide live on the Internet on a chat room website. [ 18 ]

Main articles: Video Relay Service. a telecommunication service for deaf, hard-of-hearing and speech-impaired (mute) individuals communicating with hearing persons at a different location, and Video Remote Interpreting. used where deaf/hard-of-hearing/mute persons are in the same location as their hearing parties

Video Interpreter sign used at VRS/VRI service locations

One of the first demonstrations of the ability for telecommunications to help sign language users communicate with each other occurred when AT&T 's videophone (trademarked as the "Picturephone") was introduced to the public at the 1964 New York World's Fair –two deaf users were able to communicate freely with each other between the fair and another city. [ 19 ] Various other organizations, including British Telecom's Martlesham facility and several universities have also conducted extensive research on signing via videotelephony. [ 20 ] The use of sign language via videotelephony was hampered for many years due to the difficulty of its use over slow analogue copper phone lines coupled with the high cost of better quality ISDN (data) phone lines. [ 20 ] Those factors largely disappeared with the introduction of more efficient video codecs and the advent of lower cost high-speed ISDN data and IP (Internet) services in the 1990s.

Coupled with similar high-quality videophones introduced by other electronics manufacturers, the availability of high speed Internet. and sponsored video relay services authorized by the U.S. Federal Communications Commission in 2002, VRS services for the deaf underwent rapid growth in that country. [ 21 ]

A Video Interpreter (V.I.) assisting an on-screen client. (Courtesy: SignVideo )

Multilingual sign language interpreters, who can also translate as well across principal languages (such as to and from SSL, to and from spoken English), are also available, albeit less frequently. Such activities involve considerable effort on the part of the translator, since sign languages are distinct natural languages with their own construction. semantics and syntax. different from the aural version of the same principal language.

With video interpreting, sign language interpreters work remotely with live video and audio feeds, so that the interpreter can see the deaf or mute party, and converse with the hearing party, and vice versa. Much like telephone interpreting. video interpreting can be used for situations in which no on-site interpreters are available. However, video interpreting cannot be used for situations in which all parties are speaking via telephone alone. VRS and VRI interpretation requires all parties to have the necessary equipment. Some advanced equipment enables interpreters to control the video camera remotely, in order to zoom in and out or to point the camera toward the party that is signing.

Videophone calls (also: videocalls and video chat ), [ 22 ] differ from videoconferencing in that they expect to serve individuals, not groups. However that distinction has becoming increasingly blurred with technology improvements such as increased bandwidth and sophisticated software clients that can allow for multiple parties on a call. In general everyday usage the term videoconferencing is now frequently used instead of videocall for point-to-point calls between two units. Both videophone calls and videoconferencing are also now commonly referred to as a video link .

Webcams are popular, relatively low cost devices which can provide live video and audio streams via personal computers, and can be used with many software clients for both video calls and videoconferencing. [ 23 ]

A videoconference system is generally higher cost than a videophone and deploys greater capabilities. A videoconference (also known as a videoteleconference ) allows two or more locations to communicate via live, simultaneous two-way video and audio transmissions. This is often accomplished by the use of a multipoint control unit (a centralized distribution and call management system) or by a similar non-centralized multipoint capability embedded in each videoconferencing unit. Again, technology improvements have circumvented traditional definitions by allowing multiple party videoconferencing via web-based applications. [ 24 ] [ 25 ] A separate webpage article is devoted to videoconferencing .

A telepresence system is a high-end videoconferencing system and service usually employed by enterprise-level corporate offices. Telepresence conference rooms use state-of-the art room designs, video cameras, displays, sound-systems and processors, coupled with high-to-very-high capacity bandwidth transmissions.

Typical uses of the various technologies described above include videocalling or videoconferencing on a one-to-one, one-to-many or many-to-many basis for personal, business, educational, deaf Video Relay Service and tele-medical, diagnostic and rehabilitative use or services. New services utilizing videocalling and videoconferencing, such as personal videocalls to inmates incarcerated in penitentiaries. and videoconferencing to resolve airline engineering issues at maintenance facilities. are being created or evolving on an on-going basis.

• List of webcams for use on personal computers
• Robbins v. Lower Merion School District: U.S. legal action by parents against a high school board for invasion of privacy
• Telepresence
• Video camera
• Video Relay Service. for deaf and hard-of-hearing users
• Videoconferencing
• Videophone
• Videotelephony