Webcam

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A typical webcam

Webcam on monitor

Webcams are video capturing devices connected to computers or computer networks, often using USB or, if they connect to networks, ethernet or Wi-Fi. They are well-known for their low manufacturing costs and flexible applications.

[edit] History

Started in 1991, the first such camera, 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, Apple and other computer hardware manufactures began building webcams directly into laptop and desktop screens. This eliminates the need to use an external USB or Firewire webcam.

[edit] Web-accessible cameras

This Axis camera can be connected directly to a network or the Internet, via an RJ45 connector on its rear. Users can access the picture by connecting to an onboard web server.

In addition to use for personal videoconferencing, it was quickly realised 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 (Metrocams) 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.

[edit] Software

Webcams connected to PCs can act as web-accessible cameras with certain software. Usually this kind of software works with most webcams, since the software auto-detects the peripheral. Many different programs are available, free, open source, and proprietary.

Webcam software can be configured in many ways. Some software^[specify] come with motion detection ability and time lapse capture options or both.^[5]. Captures can be short videos in predefined length or still images. Thus, the software can essentially turn the web cam into a security camera. Many businesses and home owners can effectively use a simple webcam device to create their own security system with only a webcam and one of these types of software applications.

The captured files can be saved locally, uploaded to an internet server (via FTP or HTTP) (from which they can be made accessible to anyone over the web), or privately e-mailed to the user per predefined rules. Options for image size and quality, overlaying logos, and time stamping images are usually available. File names can be sequential numbers or current time. Some software allow automatic erasure of old files when not needed.

Some software^[specify] can remotely control certain brands of cameras, allowing rotation and tilting.

[edit] Videoconferencing

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. Increased video quality has helped webcams encroach on traditional video conferencing systems. New features such as lighting, real-time enhancements (retouching, wrinkle smoothing and vertical stretch) can make users more comfortable, further increasing popularity. Features and performance vary between programs.

Videoconferencing support is included in programs including Yahoo Messenger, AOL Instant Messenger (AIM), Windows Live Messenger, Skype, iChat, Paltalk (now PaltalkScene), Ekiga , Stickam,Tokbox, Camfrog 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 two different places. Among others, BloggingHeads.tv uses this technology to set up conversations between prominent journalists, scientists, bloggers, and philosophers.

[edit] Video security

Webcams are being used for security purposes. Software is available allowing PC-connected cameras to watch for movement and sound, recording both when they are detected; these recordings can be saved to the computer, e-mailed or uploaded to the internet. In one well-publicised case,^[6] 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.

[edit] As a control input 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.

[edit] Aggregators

Due to the increasing volume 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. In the sector of recreation and leisure, Webcams.travel is evolving as another such aggregator with a special focus on webcams interesting for traveling and holiday planning. These travel webcams are of such interest that they are also in the gallery of Google Earth as a default layer.

[edit] 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. 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 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^[7] 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.

[edit] Privacy

Some 'Trojan horse' programs can allow malicious hackers to activate a computer's camera without the user's knowledge, providing the hacker with a live video feed from the unfortunate user's camera. 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.

In mid-January 2005 some search engine queries were published in an on-line forum^[8] which allow anyone to find thousands of Panasonic- and Axis-made high-end web cameras accessible through the web. Many such cameras are running on default configuration, which does not require any password login or IP address verification, making them visible to anyone.

[edit] Effects on modern society

[edit] 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.^[9] YouTube is yet another example of amateur production of extremely famous video material.

[edit] Possible 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.^[10]

[edit] See also

• List of digital camera brands
• Video camera

[edit] References

Wikimedia Commons has media related to: Category:Webcams