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[[File:Webcam000c1.jpg|thumb|225px|Typical low-cost webcam used with many personal computers]]
[[File:Webcam CT transmissions.OGG|thumb|225px|Animated set of X-ray images of a webcam. Images acquired using [[Industrial computed tomography scanning|industrial CT scanning]].]]
[[File:SumburghHead webcam.jpg|thumb|A webcam installed near [[Sumburgh Head]] lighthouse, ([[Shetland]])]]
A '''webcam''' is a [[video camera]] that feeds or [[Streaming media|streams]] its image in real time to or through a [[computer]] to a [[computer network]]. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks travelling through systems such as the internet, and e-mailed as an attachment. When sent to a remote location, the video stream may be saved, viewed or on sent there. Unlike an [[IP camera]] (which connects using [[Ethernet]] or [[Wi-Fi]]), a webcam is generally connected by a [[USB]] cable, or similar cable, or built into computer hardware, such as laptops.
The term "webcam" (a [[clipped compound]]) may also be used in its original sense of a [[video camera]] connected to the [[World Wide Web|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 camera]]s, are expensive, rugged [[professional video camera]]s.
== Characteristics ==
Webcams are known for their low [[manufacturing]] cost and their high flexibility,<ref>Solomon Negash, Michael E. Whitman. Editors: Solomon Negash, Michael E. Whitman, Amy B. Woszczynski, Ken Hoganson, Herbert Mattord. [https://books.google.com/books?id=Cz4aIXq5z8YC Handbook of Distance Learning for Real-Time and Asynchronous Information Technology Education], Idea Group Inc (IGI), 2008, p. 17, {{ISBN|1-59904-964-3}}, {{ISBN|978-1-59904-964-9}}. Note costing: "students had the option to install a webcam on their end (a basic webcam costs about $40.00) to view the class in session."</ref> making them the lowest-cost form of [[videotelephony]]. Despite the low cost, the [[Image resolution|resolution]] offered at present (2015) is rather impressive, with low-end webcams offering resolutions of 320×240, medium webcams offering 640×480 resolution, and high-end webcams offering 1280×720 (aka [[720p]]) or even 1920×1080 (aka [[1080p]]) resolution.<ref>{{cite web|url=http://www.ebay.com/gds/How-Much-Resolution-is-Enough-Picking-a-Webcam-/10000000177742678/g.html|title=How Much Resolution is Enough? Picking a Webcam|work=eBay|accessdate=29 July 2015}}</ref><ref>{{cite web|url=http://webcam-review.toptenreviews.com/1080p-2.0-mega-pixels-understanding-webcam-technical-terms.html|title=1080p, 2.0 Mega Pixels? Understanding Webcam Technical Terms|author=Jonathan Knoder|date=9 May 2013|work=Top Ten Reviews|accessdate=29 July 2015}}</ref><ref>{{cite web|url=http://lifehacker.com/5961369/five-best-webcams|title=Five Best Webcams|author=Alan Henry|publisher=Gawker Media|work=Lifehacker|accessdate=29 July 2015}}</ref>
They have also become a source of security and privacy issues, as some built-in webcams can be remotely activated by [[spyware]].
== Uses ==
The most popular use of webcams is the establishment of [[videotelephony|video links]], permitting computers to act as [[videophone]]s or [[video conferencing|videoconference station]]s. Other popular uses include security surveillance, [[computer vision]], video broadcasting, and for recording social videos.
The video streams provided by webcams can be used for a number of purposes, each using appropriate software:
=== Health care ===
Most modern webcams are capable of [http://sourceforge.net/projects/pulsecapture/ capturing arterial pulse rate] by the use of a simple algorithmic trick. Researchers claim that this method is accurate to ±5 bpm.
=== Video monitoring ===
Webcams may be installed at places such as childcare centres, offices, shops and private areas to monitor security and general activity.
=== Commerce ===
Webcams have been used for [[augmented reality]] experiences online. One such function has the webcam act as a "magic mirror" to allow an online shopper to view a virtual item on themselves. The [[Webcam Social Shopper]] is one example of software that utilizes the webcam in this manner.<ref>[http://techland.time.com/2011/08/05/augmented-reality-lets-you-try-on-clothes-from-online-shops/ "Augmented Reality Lets You Try On Clothes from Online Shops"] [[TIME]], 5 August 2011, retrieved 4 July 2012.</ref>
=== Videocalling and videoconferencing ===
{{Further information|Videophone|Videoconferencing|Videotelephony}}
Webcam can be 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 [[Personal computer|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 [[Facial motion capture|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 [[computer program|program]], [[operating system|computer operating system]], and also by the computer's [[Central processing unit|processor]] capabilities. Video calling support has also been added to several [[List of video telecommunication services and product brands#Software clients –free instant messaging programs|popular instant messaging programs]].
=== Video security ===
Webcams can be used as [[security camera]]s. Software is available to allow PC-connected cameras to watch for movement and sound,<ref>[http://www.e-consystems.com/PR/PressRelease_e-con_Announces_3MP_AutoFocus_Camera.pdf USB Camera with integrated UVC+UAC and Autofocus CMOS OV3640 CMOS Image sensor]</ref> 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,<ref>[http://news.bbc.co.uk/1/hi/england/cambridgeshire/4272041.stm Serial burglar caught on webcam] [[BBC News]], February 16, 2005, retrieved January 3, 2006.</ref> 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.
Unauthorized access of webcams can present significant privacy issues (see "Privacy" section below).
In December 2011, Russia announced that 290,000 Webcams would be installed in 90,000 polling stations to monitor the [[Russian presidential election, 2012]].<ref>[https://blogs.wsj.com/emergingeurope/2012/01/16/russia-election-webcams-linked-to-site-blamed-for-piracy/ Russia Election Webcams] ''The Wall Street Journal'', January 16, 2012.</ref>
===Video clips and stills===
Webcams can be used to take [[video clip]]s and [[Digital photography|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 (computer)|Mac]]), or [[Cheese (software)|Cheese]] (with [[Unix]] systems). For a more complete list see [[Comparison of webcam software]].
=== Input control devices ===
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 enable [[hands-free computing]] and would greatly improve [[computer accessibility]]. This can 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 (mechanics)|degrees of freedom]] and output data to mouse, keyboard, joystick and [[List of games compatible with FreeTrack|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]], [[PlayStation Eye]] for the [[PlayStation 3]], and the [[Xbox Live Vision]] camera and [[Kinect]] motion sensor for the [[Xbox 360]] and are color digital cameras that have been used as control input devices by some games.
Small webcam-based [[PC Games (magazine)|PC games]] are available as either standalone executables or inside web browser windows using [[Adobe Flash]].
=== Astro photography ===
With very-low-light capability, a few specific models of webcams are very popular to photograph the night sky by astronomers and astro photographers. Mostly, these are manual-focus cameras and contain an old CCD array instead of comparatively newer CMOS array. 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.
===Laser beam profiling===
A webcam's CCD response is linear proportional to the incoming light. <ref>Cignoli F, De Iuliis S, Zizak GA. Webcam as a light probe beam profiler. Appl. Spectrosc. 58, (2004), 1372.</ref> Therefore, webcams are suitable to record laser beam profiles, after the lens is removed. The resolution of a [[laser beam profiler]] depends on the pixel size. Commercial webcams are usually designed to record color images. The size of a webcam's color pixel depends on the model and may lie in the range of 5 to 10µm. However, a color pixel consists of four black and white pixels each equipped with a color filter (for details see [[Bayer filter]]). Although these color filters work well in the visible, they may be rather transparent in the near infra-red. By switching a webcam into the Bayer-mode it is possible to access the information of the single pixels and a resolution below 3µm was possible. <ref>G. Langer et al., A webcam in Bayer-mode as a light beam profiler for the near infra-red, Optics and Lasers in Engineering 51 (2013) 571–575 </ref>
== History ==
{{See also|History of videotelephony}}
=== Early development ===
First developed in 1991, a webcam was pointed at the [[Trojan Room coffee pot]] in the [[University of Cambridge|Cambridge University]] Computer Science Department (initially operating over a local network instead of the web). The camera was finally switched off on August 22, 2001. The final image captured by the camera can still be viewed at its homepage.<ref>[http://www.cl.cam.ac.uk/coffee/coffee.html CoffeeCam], University of Cambridge.</ref><ref>{{cite web|url=http://www.spiegel.de/static/popup/coffeecam/cam2.html|title=Trojan Room Coffee Pot - SPIEGEL ONLINE|publisher=|accessdate=29 July 2015}}</ref> In 2004, the oldest webcam still operating was FogCam at [[San Francisco State University]], which had been running continuously since 1994.<ref>[http://xpress.sfsu.edu/archives/life/001905.html "Happy Birthday Fogcam"] by Anjuli Elais in ''Golden Gate XPress'', September 30, 2004</ref>
=== Connectix QuickCam ===
The first commercial webcam, the black-and-white [[QuickCam]], entered the marketplace in 1994, created by the U.S. computer company [[Connectix]] (which sold its product line to [[Logitech]] in 1998). QuickCam was available in August 1994 for the [[Apple Macintosh]], connecting via a [[serial port]], at a cost of $100. Jon Garber, the designer of the device, had wanted to call it the "Mac-camera", but was overruled by Connectix's marketing department; a version with a PC-compatible parallel port and software for [[Microsoft Windows]] was launched in October 1995. The original QuickCam provided 320x240-pixel resolution with a grayscale depth of 16 shades at 60 frames per second, or 256 shades at 15 frames per second.<ref>Edwards, Benj. [http://www.pcworld.com/article/199112/victorian_scifi.html History of Video Calls: From Fantasy to Flops to Facetime], [[PC World (magazine)|PC World Magazine]], June 17, 2010.</ref> These cam were tested on several Delta II launch using a variety of communication protocols including CDMA, TDMA, GSM and HF.
In 2010, [[Time Magazine]] named the QuickCam as one of the top computer devices of all time.<ref>Ha, Peter. [http://www.time.com/time/specials/packages/article/0,28804,2023689_2023703_2023628,00.html Computing: Connectix QuickCam], [[Time Magazine]], October 25, 2010.</ref>
[[Videoconferencing]] via computers already existed, and at the time [[Client–server model|client-server]] based videoconferencing software such as [[CU-SeeMe]] had started to become popular.
=== Later developments ===
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 television|reality TV series]] ''[[Big Brother (TV series)|Big Brother]]'', launched four years later.<ref>[https://www.theguardian.com/international/story/0,,1115262,00.html "Plug pulled on live website seen by millions"] by Oliver Burkeman in ''The Guardian'', January 3, 2004</ref> 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 telecommunications, or [[videotelephony]], between two people, or among several people, than for offering a view on a Web page to an unknown public.
For less than US$100 in 2012, a [[three-dimensional|three-dimensional space]] webcam became available, producing videos and photos in 3D [[anaglyph image]] with a resolution up to 1280 × 480 pixels. Both sender and receiver of the images must use 3D glasses to see the effect of three dimensional image.<ref>{{cite web|last=Lanxon |first=Nate |url=http://crave.cnet.co.uk/gadgets/3d-photos-minoru-3d-webcam-hands-on-49303012/ |title=3D photos: Minoru 3D webcam hands-on | CNET UK |publisher=Crave.cnet.co.uk |date=2009-07-16 |accessdate=2013-01-07}}</ref>
== Technology ==
[[File:Sweex USB webcam PCB with without lens close up.jpg|thumb|225px|right|Webcams typically include a lens (shown at top), an image sensor (shown at bottom), and supporting circuitry]]
Webcams typically include a lens, an [[image sensor]], 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 (optics)|lens]] that can be screwed in and out to focus the camera. [[Fixed-focus lens]]es, 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 [[Charge-coupled device|CCD]], the former being dominant for low-cost cameras, but CCD cameras do not necessarily outperform CMOS-based cameras in the low-price range. Most consumer webcams are capable of providing [[Video Graphics Array|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 [[Quarter VGA|320×240]] video at 120 frames per second.
Support electronics 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 [[Universal Serial Bus|USB]]. Typically, each frame is transmitted uncompressed in [[RGB]] or [[YUV]] or compressed as [[JPEG]]. Some cameras, such as [[camera phone|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 [[Integrated circuit|silicon chip]] to save space and manufacturing costs. Most webcams feature built-in [[microphone]]s to make [[videotelephone|video calling]] and [[videoconferencing]] more convenient.
The [[USB video device class]] (UVC) specification allows interconnectivity of webcams to computers without the need for proprietary device drivers. Microsoft [[Windows XP]] SP2, [[Linux]]<ref>{{cite web|url=http://kernelnewbies.org/Linux_2_6_26#head-6d4ee1ddea983f5c8ac491b8685a94ea6fa4132b|title=Linux 2 6 26|publisher=|accessdate=29 July 2015}}</ref> and [[Mac OS X]] (since October 2005) have UVC support built in and do not require extra device drivers, although they are often installed to add additional features.
== Privacy ==
Many users do not wish the continuous exposure for which webcams were originally intended, but rather prefer privacy.<ref>{{cite web|url=http://br.noticias.yahoo.com/jogador-esquece-webcam-ligada-transmite-sexo-namorada.html|title=Jogador esquece webcam ligada e transmite sexo com namorada|date=13 November 2012|work=Yahoo Notícias|accessdate=29 July 2015}}</ref> Such privacy is lost when [[malware]] allow [[Hacker (computer security)|malicious hackers]] to activate the webcam without the user's knowledge, providing the hackers with a live video and audio feed.<ref>{{cite book|last=Gray|first=Leon|title=Virtual crime! : solving cybercrime|year=2009|publisher=Enslow Publishers|location=Berkeley Heights, NJ|isbn=0766033767|url=https://books.google.com/books?hl=en&lr=&id=B2utHHdYJOcC&oi=fnd&pg=PA5&dq=ivacy+is+lost+when+Trojan+horse+programs+allow+malicious+hackers+to+activate+the+webcam+&ots=6xUolQ_x9M&sig=uUxTma9QTdwOzn1sma4bgzUAqkU#v=onepage&q&f=false}}</ref> This is a particular concern on many laptop computers, as such cameras normally cannot be physically disabled if hijacked by such a [[Trojan Horse]] program or other similar [[spyware]] programs.
Cameras such as [[Apple Computer|Apple]]'s older external [[iSight]] cameras include lens covers to thwart this. Some webcams have built-in hardwired [[Light-emitting diode|LED]] indicators that light up whenever the camera is active, sometimes only in video mode{{Citation needed|date=September 2013}}. However, it is possible for [[malware]] to circumvent the indicator and activate the camera surrepticiously, as researchers demonstrated in the case of a [[MacBook]]'s built-in camera in 2013.<ref name=":0">{{Cite web|url=https://www.theguardian.com/world/2016/jun/06/surveillance-camera-laptop-smartphone-cover-tape|title=Why is everyone covering up their laptop cameras?|last=Yadron|first=Danny|date=2016-06-06|website=the Guardian|access-date=2016-06-13}}</ref>
Various companies sell sliding lens covers and stickers that allow users to retrofit a computer or smartphone to close access to the camera lens as needed.<ref name=":0" /> One such company reported having sold more than 250,000 such items from 2013 to 2016.<ref name=":0" /> However, any opaque material will work. Prominent users include former FBI director [[James Comey]].<ref name=":0" />
The fraudulent process of attempting to hack into a person's webcam and activate it without the webcam owner's permission has been called [[camfecting]]. The remotely activated webcam can be used to watch anything within the webcam's field of vision, sometimes the webcam owner itself. Camfecting is most often carried out by infecting the victim's computer with a virus that can provide the hacker access to the victim's webcam. This attack is specifically targeted at the victim's webcam, and hence the name ''camfecting'', a [[portmanteau]] of the words ''cam'' and ''infecting''.
In January 2005, some [[Web search engine|search engine]] queries were published in an online forum<ref>[https://www.theregister.co.uk/2005/01/08/web_surveillance_cams_open_to_all/ "Google exposes web surveillance cams"] by Kevin Poulsen, ''The Register'', January 8, 2005, retrieved September 5, 2006</ref> which allow anyone to find thousands of [[Panasonic]]- and [[Axis Communications|Axis]] high-end web cameras, provided that they have a web-based [[Interface (computing)|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 viewable by anyone.
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.<ref name="USATODAY">{{cite news|url=http://content.usatoday.com/communities/ondeadline/post/2010/02/school-district-accused-of-issuing-webcam-laptops-to-spy-on-students/1|author=Doug Stanglin|title=School district accused of spying on kids via laptop webcams|date=February 18, 2010|work=[[USA Today]]|accessdate=February 19, 2010}}</ref><ref name="autogenerated5">[http://lmsd.org/documents/news/100503_l3_report.pdf "Initial LANrev System Findings"], LMSD Redacted Forensic Analysis, L-3 Services – prepared for [[Ballard Spahr]] (LMSD's counsel), May 2010. Retrieved August 15, 2010.</ref> The school board involved quickly disabled their laptop spyware program after parents filed lawsuits against the board and various individuals.<ref>{{cite web|last=Holmes |first=Kristin E. |url=http://www.philly.com/inquirer/local/pa/20100831_Lower_Merion_School_District_ordered_to_pay_plaintiff_s_lawyer__260_000.html |title=Lower Merion School District ordered to pay plaintiff's lawyer $260,000 |website=The Philadelphia Inquirer |date=August 31, 2010 |accessdate=September 20, 2010}}</ref><ref>{{cite web|url=http://mainlinemedianews.com/articles/2010/08/31/main_line_times/news/doc4c7cfdad3e059461146296.txt |title=. |publisher=Main Line Media News |date=September 18, 2010 |accessdate=September 20, 2010}}</ref>
== Effects on modern society ==
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 [[camgirl]]ing. However, the ease of webcam use through the Internet for video chat has also caused issues. For example, moderation system of various video chat websites such as [[Omegle]] has been criticized as being ineffective, with sexual content still rampant.<ref>{{cite web|title=The Problems with Omegle Girls and Free Chat Services|url=http://www.omeglegirlschat.com/omegle-controversy|publisher=OmegleGirlsChat|accessdate=14 May 2013}}</ref> In a 2013 case, the transmission of nude photos and videos via Omegle from a teenage girl to a schoolteacher resulted in a [[child pornography]] charge.<ref>{{cite web|title=Ex-band teacher pleads guilty to porn charge with girl, 16|url=http://www.jconline.com/article/20130426/NEWS03/304260027/child-porn-former-teacher-nude-photos|publisher=jconline.com|accessdate=14 May 2013}}</ref>
[[YouTube]] is a popular website hosting many videos made using webcams. News websites such as the [[British Broadcasting Corporation|BBC]] also produce professional live news videos using webcams rather than traditional cameras.<ref>{{cite web|url=http://www.bbc.co.uk/london/content/webcams/bbclondon_studio_webcam.shtml|title=BBC - London - In Pictures - BBC London Radio Studio 1|publisher=|accessdate=29 July 2015}}</ref>{{better source|date=September 2013|reason=The link says nothing about the type of camera.}}
Webcams can also encourage [[telecommuting]], enabling people to work from home via the Internet, rather than traveling to their office.
The popularity of webcams among teenagers with Internet access has raised concern about the use of webcams for [[cyber-bullying]].<ref>Poeter, Damon. "[https://www.pcmag.com/article2/0,2817,2401701,00.asp Webcam Peeper Convicted in Rutgers Cyberbullying Case]," ''[[PC Magazine]],'' March 16, 2012.</ref> Webcam recordings of teenagers, including underage teenagers, are frequently posted on popular Web forums and [[imageboard]]s such as [[4chan]].<ref>[http://www.thesmokinggun.com/buster/4chan-reports-child-pornographer-769123 Tip From 4chan Leads To Arrest Of Site Visitor On Child Porn Charges]," ''[[The Smoking Gun]],'' February 27, 2012.</ref><ref>Goodin, Dan. [https://www.theregister.co.uk/2009/10/13/predator_indictment/ Feds: bald man posing as 17-year-old secretly taped teens]," ''[[The Register]]'' (UK), October 13, 2009.</ref>
== Descriptive names and terminology ==
''Videophone calls'' (also: ''[[videocalls]]'' and ''[[video chat]]''),<ref>PC Magazine. [https://www.pcmag.com/encyclopedia_term/0,2542,t=video+calling&i=61765,00.asp Definition: Video Calling], PC Magazine website. Retrieved 19 August 2010,</ref> differ from [[videoconferencing]] in that they expect to serve individuals, not groups.<ref name="Mulbach-1995c">Mulbach, 1995. Pg. 291.</ref> However that distinction has become increasingly blurred with technology improvements such as [[Broadband Internet access|increased bandwidth]] and sophisticated [[software client]]s 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 [[List of video telecommunication services and product brands#Software Client brands|software clients]] for both video calls and videoconferencing.<ref>
Solomon Negash, Michael E. Whitman. Editors: Solomon Negash, Michael E. Whitman, Amy B. Woszczynski, Ken Hoganson, Herbert Mattord. [https://books.google.com/books?id=Cz4aIXq5z8YC ''Handbook of Distance Learning for Real-Time and Asynchronous Information Technology Education''], Idea Group Inc (IGI), 2008, pg. 17, {{ISBN|1-59904-964-3}}, {{ISBN|978-1-59904-964-9}}. Note costing: "....students had the option to install a webcam on their end (a basic webcam costs about $40.00) to view the class in session."</ref>
A [[List of video telecommunication services and product brands#Video conferencing systems meant for multiple participants|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.<ref>Lawson, Stephen. [http://www.computerworld.com/s/article/9157818/Vidyo_packages_conferencing_for_campuses Vidyo Packages Conferencing For Campuses], IDG News Service, February 16, 2010. Retrieved via Computerworld.com's website, February 18, 2010</ref><ref>Jackman, Elizabeth. [http://peoriatimes.com/articles/2010/02/19/news/news06.txt New Video Conferencing System Streamlines Firefighter Training], ''Peoria Times'', Peoria, AZ, February 19, 2010. Retrieved February 19, 2010;</ref>
A separate webpage article is devoted to [[videoconferencing]].
A [[Telepresence|telepresence system]] is a high-end videoconferencing system and service usually employed by [[company|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 use of the various technologies described above include calling or conferencing on a one-on-one, one-to-many or many-to-many basis for personal, business, educational, [[Video Relay Service|deaf Video Relay Service]] and [[telemedicine|tele-medical, diagnostic]] and [[telerehabilitation|rehabilitative]] use or services. New services utilizing videocalling and videoconferencing, such as teachers and psychologists conducting online sessions,<ref name="USAToday-2010.03.31">
'''USA Today'''. "Video Chat Growing by Light-Year Leaps", ''[[USA Today]]'', March 31, 2010, p. L01d.
</ref> personal videocalls to [[prison|inmates incarcerated in penitentiaries]], and videoconferencing to resolve [[Aircraft maintenance checks|airline engineering issues]] at [[hangar|maintenance facilities]], are being created or evolving on an ongoing basis.
[[File:Webcam CT transmissions.OGG|thumb|225px|Animated set of X-ray images of a webcam. Images acquired using [[Industrial computed tomography scanning|industrial CT scanning]].]]
[[File:SumburghHead webcam.jpg|thumb|A webcam installed near [[Sumburgh Head]] lighthouse, ([[Shetland]])]]
A '''webcam''' is a [[video camera]] that feeds or [[Streaming media|streams]] its image in real time to or through a [[computer]] to a [[computer network]]. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks travelling through systems such as the internet, and e-mailed as an attachment. When sent to a remote location, the video stream may be saved, viewed or on sent there. Unlike an [[IP camera]] (which connects using [[Ethernet]] or [[Wi-Fi]]), a webcam is generally connected by a [[USB]] cable, or similar cable, or built into computer hardware, such as laptops.
The term "webcam" (a [[clipped compound]]) may also be used in its original sense of a [[video camera]] connected to the [[World Wide Web|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 camera]]s, are expensive, rugged [[professional video camera]]s.
== Characteristics ==
Webcams are known for their low [[manufacturing]] cost and their high flexibility,<ref>Solomon Negash, Michael E. Whitman. Editors: Solomon Negash, Michael E. Whitman, Amy B. Woszczynski, Ken Hoganson, Herbert Mattord. [https://books.google.com/books?id=Cz4aIXq5z8YC Handbook of Distance Learning for Real-Time and Asynchronous Information Technology Education], Idea Group Inc (IGI), 2008, p. 17, {{ISBN|1-59904-964-3}}, {{ISBN|978-1-59904-964-9}}. Note costing: "students had the option to install a webcam on their end (a basic webcam costs about $40.00) to view the class in session."</ref> making them the lowest-cost form of [[videotelephony]]. Despite the low cost, the [[Image resolution|resolution]] offered at present (2015) is rather impressive, with low-end webcams offering resolutions of 320×240, medium webcams offering 640×480 resolution, and high-end webcams offering 1280×720 (aka [[720p]]) or even 1920×1080 (aka [[1080p]]) resolution.<ref>{{cite web|url=http://www.ebay.com/gds/How-Much-Resolution-is-Enough-Picking-a-Webcam-/10000000177742678/g.html|title=How Much Resolution is Enough? Picking a Webcam|work=eBay|accessdate=29 July 2015}}</ref><ref>{{cite web|url=http://webcam-review.toptenreviews.com/1080p-2.0-mega-pixels-understanding-webcam-technical-terms.html|title=1080p, 2.0 Mega Pixels? Understanding Webcam Technical Terms|author=Jonathan Knoder|date=9 May 2013|work=Top Ten Reviews|accessdate=29 July 2015}}</ref><ref>{{cite web|url=http://lifehacker.com/5961369/five-best-webcams|title=Five Best Webcams|author=Alan Henry|publisher=Gawker Media|work=Lifehacker|accessdate=29 July 2015}}</ref>
They have also become a source of security and privacy issues, as some built-in webcams can be remotely activated by [[spyware]].
== Uses ==
The most popular use of webcams is the establishment of [[videotelephony|video links]], permitting computers to act as [[videophone]]s or [[video conferencing|videoconference station]]s. Other popular uses include security surveillance, [[computer vision]], video broadcasting, and for recording social videos.
The video streams provided by webcams can be used for a number of purposes, each using appropriate software:
=== Health care ===
Most modern webcams are capable of [http://sourceforge.net/projects/pulsecapture/ capturing arterial pulse rate] by the use of a simple algorithmic trick. Researchers claim that this method is accurate to ±5 bpm.
=== Video monitoring ===
Webcams may be installed at places such as childcare centres, offices, shops and private areas to monitor security and general activity.
=== Commerce ===
Webcams have been used for [[augmented reality]] experiences online. One such function has the webcam act as a "magic mirror" to allow an online shopper to view a virtual item on themselves. The [[Webcam Social Shopper]] is one example of software that utilizes the webcam in this manner.<ref>[http://techland.time.com/2011/08/05/augmented-reality-lets-you-try-on-clothes-from-online-shops/ "Augmented Reality Lets You Try On Clothes from Online Shops"] [[TIME]], 5 August 2011, retrieved 4 July 2012.</ref>
=== Videocalling and videoconferencing ===
{{Further information|Videophone|Videoconferencing|Videotelephony}}
Webcam can be 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 [[Personal computer|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 [[Facial motion capture|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 [[computer program|program]], [[operating system|computer operating system]], and also by the computer's [[Central processing unit|processor]] capabilities. Video calling support has also been added to several [[List of video telecommunication services and product brands#Software clients –free instant messaging programs|popular instant messaging programs]].
=== Video security ===
Webcams can be used as [[security camera]]s. Software is available to allow PC-connected cameras to watch for movement and sound,<ref>[http://www.e-consystems.com/PR/PressRelease_e-con_Announces_3MP_AutoFocus_Camera.pdf USB Camera with integrated UVC+UAC and Autofocus CMOS OV3640 CMOS Image sensor]</ref> 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,<ref>[http://news.bbc.co.uk/1/hi/england/cambridgeshire/4272041.stm Serial burglar caught on webcam] [[BBC News]], February 16, 2005, retrieved January 3, 2006.</ref> 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.
Unauthorized access of webcams can present significant privacy issues (see "Privacy" section below).
In December 2011, Russia announced that 290,000 Webcams would be installed in 90,000 polling stations to monitor the [[Russian presidential election, 2012]].<ref>[https://blogs.wsj.com/emergingeurope/2012/01/16/russia-election-webcams-linked-to-site-blamed-for-piracy/ Russia Election Webcams] ''The Wall Street Journal'', January 16, 2012.</ref>
===Video clips and stills===
Webcams can be used to take [[video clip]]s and [[Digital photography|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 (computer)|Mac]]), or [[Cheese (software)|Cheese]] (with [[Unix]] systems). For a more complete list see [[Comparison of webcam software]].
=== Input control devices ===
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 enable [[hands-free computing]] and would greatly improve [[computer accessibility]]. This can 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 (mechanics)|degrees of freedom]] and output data to mouse, keyboard, joystick and [[List of games compatible with FreeTrack|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]], [[PlayStation Eye]] for the [[PlayStation 3]], and the [[Xbox Live Vision]] camera and [[Kinect]] motion sensor for the [[Xbox 360]] and are color digital cameras that have been used as control input devices by some games.
Small webcam-based [[PC Games (magazine)|PC games]] are available as either standalone executables or inside web browser windows using [[Adobe Flash]].
=== Astro photography ===
With very-low-light capability, a few specific models of webcams are very popular to photograph the night sky by astronomers and astro photographers. Mostly, these are manual-focus cameras and contain an old CCD array instead of comparatively newer CMOS array. 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.
===Laser beam profiling===
A webcam's CCD response is linear proportional to the incoming light. <ref>Cignoli F, De Iuliis S, Zizak GA. Webcam as a light probe beam profiler. Appl. Spectrosc. 58, (2004), 1372.</ref> Therefore, webcams are suitable to record laser beam profiles, after the lens is removed. The resolution of a [[laser beam profiler]] depends on the pixel size. Commercial webcams are usually designed to record color images. The size of a webcam's color pixel depends on the model and may lie in the range of 5 to 10µm. However, a color pixel consists of four black and white pixels each equipped with a color filter (for details see [[Bayer filter]]). Although these color filters work well in the visible, they may be rather transparent in the near infra-red. By switching a webcam into the Bayer-mode it is possible to access the information of the single pixels and a resolution below 3µm was possible. <ref>G. Langer et al., A webcam in Bayer-mode as a light beam profiler for the near infra-red, Optics and Lasers in Engineering 51 (2013) 571–575 </ref>
== History ==
{{See also|History of videotelephony}}
=== Early development ===
First developed in 1991, a webcam was pointed at the [[Trojan Room coffee pot]] in the [[University of Cambridge|Cambridge University]] Computer Science Department (initially operating over a local network instead of the web). The camera was finally switched off on August 22, 2001. The final image captured by the camera can still be viewed at its homepage.<ref>[http://www.cl.cam.ac.uk/coffee/coffee.html CoffeeCam], University of Cambridge.</ref><ref>{{cite web|url=http://www.spiegel.de/static/popup/coffeecam/cam2.html|title=Trojan Room Coffee Pot - SPIEGEL ONLINE|publisher=|accessdate=29 July 2015}}</ref> In 2004, the oldest webcam still operating was FogCam at [[San Francisco State University]], which had been running continuously since 1994.<ref>[http://xpress.sfsu.edu/archives/life/001905.html "Happy Birthday Fogcam"] by Anjuli Elais in ''Golden Gate XPress'', September 30, 2004</ref>
=== Connectix QuickCam ===
The first commercial webcam, the black-and-white [[QuickCam]], entered the marketplace in 1994, created by the U.S. computer company [[Connectix]] (which sold its product line to [[Logitech]] in 1998). QuickCam was available in August 1994 for the [[Apple Macintosh]], connecting via a [[serial port]], at a cost of $100. Jon Garber, the designer of the device, had wanted to call it the "Mac-camera", but was overruled by Connectix's marketing department; a version with a PC-compatible parallel port and software for [[Microsoft Windows]] was launched in October 1995. The original QuickCam provided 320x240-pixel resolution with a grayscale depth of 16 shades at 60 frames per second, or 256 shades at 15 frames per second.<ref>Edwards, Benj. [http://www.pcworld.com/article/199112/victorian_scifi.html History of Video Calls: From Fantasy to Flops to Facetime], [[PC World (magazine)|PC World Magazine]], June 17, 2010.</ref> These cam were tested on several Delta II launch using a variety of communication protocols including CDMA, TDMA, GSM and HF.
In 2010, [[Time Magazine]] named the QuickCam as one of the top computer devices of all time.<ref>Ha, Peter. [http://www.time.com/time/specials/packages/article/0,28804,2023689_2023703_2023628,00.html Computing: Connectix QuickCam], [[Time Magazine]], October 25, 2010.</ref>
[[Videoconferencing]] via computers already existed, and at the time [[Client–server model|client-server]] based videoconferencing software such as [[CU-SeeMe]] had started to become popular.
=== Later developments ===
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 television|reality TV series]] ''[[Big Brother (TV series)|Big Brother]]'', launched four years later.<ref>[https://www.theguardian.com/international/story/0,,1115262,00.html "Plug pulled on live website seen by millions"] by Oliver Burkeman in ''The Guardian'', January 3, 2004</ref> 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 telecommunications, or [[videotelephony]], between two people, or among several people, than for offering a view on a Web page to an unknown public.
For less than US$100 in 2012, a [[three-dimensional|three-dimensional space]] webcam became available, producing videos and photos in 3D [[anaglyph image]] with a resolution up to 1280 × 480 pixels. Both sender and receiver of the images must use 3D glasses to see the effect of three dimensional image.<ref>{{cite web|last=Lanxon |first=Nate |url=http://crave.cnet.co.uk/gadgets/3d-photos-minoru-3d-webcam-hands-on-49303012/ |title=3D photos: Minoru 3D webcam hands-on | CNET UK |publisher=Crave.cnet.co.uk |date=2009-07-16 |accessdate=2013-01-07}}</ref>
== Technology ==
[[File:Sweex USB webcam PCB with without lens close up.jpg|thumb|225px|right|Webcams typically include a lens (shown at top), an image sensor (shown at bottom), and supporting circuitry]]
Webcams typically include a lens, an [[image sensor]], 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 (optics)|lens]] that can be screwed in and out to focus the camera. [[Fixed-focus lens]]es, 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 [[Charge-coupled device|CCD]], the former being dominant for low-cost cameras, but CCD cameras do not necessarily outperform CMOS-based cameras in the low-price range. Most consumer webcams are capable of providing [[Video Graphics Array|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 [[Quarter VGA|320×240]] video at 120 frames per second.
Support electronics 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 [[Universal Serial Bus|USB]]. Typically, each frame is transmitted uncompressed in [[RGB]] or [[YUV]] or compressed as [[JPEG]]. Some cameras, such as [[camera phone|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 [[Integrated circuit|silicon chip]] to save space and manufacturing costs. Most webcams feature built-in [[microphone]]s to make [[videotelephone|video calling]] and [[videoconferencing]] more convenient.
The [[USB video device class]] (UVC) specification allows interconnectivity of webcams to computers without the need for proprietary device drivers. Microsoft [[Windows XP]] SP2, [[Linux]]<ref>{{cite web|url=http://kernelnewbies.org/Linux_2_6_26#head-6d4ee1ddea983f5c8ac491b8685a94ea6fa4132b|title=Linux 2 6 26|publisher=|accessdate=29 July 2015}}</ref> and [[Mac OS X]] (since October 2005) have UVC support built in and do not require extra device drivers, although they are often installed to add additional features.
== Privacy ==
Many users do not wish the continuous exposure for which webcams were originally intended, but rather prefer privacy.<ref>{{cite web|url=http://br.noticias.yahoo.com/jogador-esquece-webcam-ligada-transmite-sexo-namorada.html|title=Jogador esquece webcam ligada e transmite sexo com namorada|date=13 November 2012|work=Yahoo Notícias|accessdate=29 July 2015}}</ref> Such privacy is lost when [[malware]] allow [[Hacker (computer security)|malicious hackers]] to activate the webcam without the user's knowledge, providing the hackers with a live video and audio feed.<ref>{{cite book|last=Gray|first=Leon|title=Virtual crime! : solving cybercrime|year=2009|publisher=Enslow Publishers|location=Berkeley Heights, NJ|isbn=0766033767|url=https://books.google.com/books?hl=en&lr=&id=B2utHHdYJOcC&oi=fnd&pg=PA5&dq=ivacy+is+lost+when+Trojan+horse+programs+allow+malicious+hackers+to+activate+the+webcam+&ots=6xUolQ_x9M&sig=uUxTma9QTdwOzn1sma4bgzUAqkU#v=onepage&q&f=false}}</ref> This is a particular concern on many laptop computers, as such cameras normally cannot be physically disabled if hijacked by such a [[Trojan Horse]] program or other similar [[spyware]] programs.
Cameras such as [[Apple Computer|Apple]]'s older external [[iSight]] cameras include lens covers to thwart this. Some webcams have built-in hardwired [[Light-emitting diode|LED]] indicators that light up whenever the camera is active, sometimes only in video mode{{Citation needed|date=September 2013}}. However, it is possible for [[malware]] to circumvent the indicator and activate the camera surrepticiously, as researchers demonstrated in the case of a [[MacBook]]'s built-in camera in 2013.<ref name=":0">{{Cite web|url=https://www.theguardian.com/world/2016/jun/06/surveillance-camera-laptop-smartphone-cover-tape|title=Why is everyone covering up their laptop cameras?|last=Yadron|first=Danny|date=2016-06-06|website=the Guardian|access-date=2016-06-13}}</ref>
Various companies sell sliding lens covers and stickers that allow users to retrofit a computer or smartphone to close access to the camera lens as needed.<ref name=":0" /> One such company reported having sold more than 250,000 such items from 2013 to 2016.<ref name=":0" /> However, any opaque material will work. Prominent users include former FBI director [[James Comey]].<ref name=":0" />
The fraudulent process of attempting to hack into a person's webcam and activate it without the webcam owner's permission has been called [[camfecting]]. The remotely activated webcam can be used to watch anything within the webcam's field of vision, sometimes the webcam owner itself. Camfecting is most often carried out by infecting the victim's computer with a virus that can provide the hacker access to the victim's webcam. This attack is specifically targeted at the victim's webcam, and hence the name ''camfecting'', a [[portmanteau]] of the words ''cam'' and ''infecting''.
In January 2005, some [[Web search engine|search engine]] queries were published in an online forum<ref>[https://www.theregister.co.uk/2005/01/08/web_surveillance_cams_open_to_all/ "Google exposes web surveillance cams"] by Kevin Poulsen, ''The Register'', January 8, 2005, retrieved September 5, 2006</ref> which allow anyone to find thousands of [[Panasonic]]- and [[Axis Communications|Axis]] high-end web cameras, provided that they have a web-based [[Interface (computing)|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 viewable by anyone.
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.<ref name="USATODAY">{{cite news|url=http://content.usatoday.com/communities/ondeadline/post/2010/02/school-district-accused-of-issuing-webcam-laptops-to-spy-on-students/1|author=Doug Stanglin|title=School district accused of spying on kids via laptop webcams|date=February 18, 2010|work=[[USA Today]]|accessdate=February 19, 2010}}</ref><ref name="autogenerated5">[http://lmsd.org/documents/news/100503_l3_report.pdf "Initial LANrev System Findings"], LMSD Redacted Forensic Analysis, L-3 Services – prepared for [[Ballard Spahr]] (LMSD's counsel), May 2010. Retrieved August 15, 2010.</ref> The school board involved quickly disabled their laptop spyware program after parents filed lawsuits against the board and various individuals.<ref>{{cite web|last=Holmes |first=Kristin E. |url=http://www.philly.com/inquirer/local/pa/20100831_Lower_Merion_School_District_ordered_to_pay_plaintiff_s_lawyer__260_000.html |title=Lower Merion School District ordered to pay plaintiff's lawyer $260,000 |website=The Philadelphia Inquirer |date=August 31, 2010 |accessdate=September 20, 2010}}</ref><ref>{{cite web|url=http://mainlinemedianews.com/articles/2010/08/31/main_line_times/news/doc4c7cfdad3e059461146296.txt |title=. |publisher=Main Line Media News |date=September 18, 2010 |accessdate=September 20, 2010}}</ref>
== Effects on modern society ==
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 [[camgirl]]ing. However, the ease of webcam use through the Internet for video chat has also caused issues. For example, moderation system of various video chat websites such as [[Omegle]] has been criticized as being ineffective, with sexual content still rampant.<ref>{{cite web|title=The Problems with Omegle Girls and Free Chat Services|url=http://www.omeglegirlschat.com/omegle-controversy|publisher=OmegleGirlsChat|accessdate=14 May 2013}}</ref> In a 2013 case, the transmission of nude photos and videos via Omegle from a teenage girl to a schoolteacher resulted in a [[child pornography]] charge.<ref>{{cite web|title=Ex-band teacher pleads guilty to porn charge with girl, 16|url=http://www.jconline.com/article/20130426/NEWS03/304260027/child-porn-former-teacher-nude-photos|publisher=jconline.com|accessdate=14 May 2013}}</ref>
[[YouTube]] is a popular website hosting many videos made using webcams. News websites such as the [[British Broadcasting Corporation|BBC]] also produce professional live news videos using webcams rather than traditional cameras.<ref>{{cite web|url=http://www.bbc.co.uk/london/content/webcams/bbclondon_studio_webcam.shtml|title=BBC - London - In Pictures - BBC London Radio Studio 1|publisher=|accessdate=29 July 2015}}</ref>{{better source|date=September 2013|reason=The link says nothing about the type of camera.}}
Webcams can also encourage [[telecommuting]], enabling people to work from home via the Internet, rather than traveling to their office.
The popularity of webcams among teenagers with Internet access has raised concern about the use of webcams for [[cyber-bullying]].<ref>Poeter, Damon. "[https://www.pcmag.com/article2/0,2817,2401701,00.asp Webcam Peeper Convicted in Rutgers Cyberbullying Case]," ''[[PC Magazine]],'' March 16, 2012.</ref> Webcam recordings of teenagers, including underage teenagers, are frequently posted on popular Web forums and [[imageboard]]s such as [[4chan]].<ref>[http://www.thesmokinggun.com/buster/4chan-reports-child-pornographer-769123 Tip From 4chan Leads To Arrest Of Site Visitor On Child Porn Charges]," ''[[The Smoking Gun]],'' February 27, 2012.</ref><ref>Goodin, Dan. [https://www.theregister.co.uk/2009/10/13/predator_indictment/ Feds: bald man posing as 17-year-old secretly taped teens]," ''[[The Register]]'' (UK), October 13, 2009.</ref>
== Descriptive names and terminology ==
''Videophone calls'' (also: ''[[videocalls]]'' and ''[[video chat]]''),<ref>PC Magazine. [https://www.pcmag.com/encyclopedia_term/0,2542,t=video+calling&i=61765,00.asp Definition: Video Calling], PC Magazine website. Retrieved 19 August 2010,</ref> differ from [[videoconferencing]] in that they expect to serve individuals, not groups.<ref name="Mulbach-1995c">Mulbach, 1995. Pg. 291.</ref> However that distinction has become increasingly blurred with technology improvements such as [[Broadband Internet access|increased bandwidth]] and sophisticated [[software client]]s 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 [[List of video telecommunication services and product brands#Software Client brands|software clients]] for both video calls and videoconferencing.<ref>
Solomon Negash, Michael E. Whitman. Editors: Solomon Negash, Michael E. Whitman, Amy B. Woszczynski, Ken Hoganson, Herbert Mattord. [https://books.google.com/books?id=Cz4aIXq5z8YC ''Handbook of Distance Learning for Real-Time and Asynchronous Information Technology Education''], Idea Group Inc (IGI), 2008, pg. 17, {{ISBN|1-59904-964-3}}, {{ISBN|978-1-59904-964-9}}. Note costing: "....students had the option to install a webcam on their end (a basic webcam costs about $40.00) to view the class in session."</ref>
A [[List of video telecommunication services and product brands#Video conferencing systems meant for multiple participants|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.<ref>Lawson, Stephen. [http://www.computerworld.com/s/article/9157818/Vidyo_packages_conferencing_for_campuses Vidyo Packages Conferencing For Campuses], IDG News Service, February 16, 2010. Retrieved via Computerworld.com's website, February 18, 2010</ref><ref>Jackman, Elizabeth. [http://peoriatimes.com/articles/2010/02/19/news/news06.txt New Video Conferencing System Streamlines Firefighter Training], ''Peoria Times'', Peoria, AZ, February 19, 2010. Retrieved February 19, 2010;</ref>
A separate webpage article is devoted to [[videoconferencing]].
A [[Telepresence|telepresence system]] is a high-end videoconferencing system and service usually employed by [[company|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 use of the various technologies described above include calling or conferencing on a one-on-one, one-to-many or many-to-many basis for personal, business, educational, [[Video Relay Service|deaf Video Relay Service]] and [[telemedicine|tele-medical, diagnostic]] and [[telerehabilitation|rehabilitative]] use or services. New services utilizing videocalling and videoconferencing, such as teachers and psychologists conducting online sessions,<ref name="USAToday-2010.03.31">
'''USA Today'''. "Video Chat Growing by Light-Year Leaps", ''[[USA Today]]'', March 31, 2010, p. L01d.
</ref> personal videocalls to [[prison|inmates incarcerated in penitentiaries]], and videoconferencing to resolve [[Aircraft maintenance checks|airline engineering issues]] at [[hangar|maintenance facilities]], are being created or evolving on an ongoing basis.
