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Computer Webcam
Webcam
From Wikipedia, the free encyclopedia
Typical low-cost webcam used with many personal computers
Wikimedia Commons has media related to: Webcams
Animated set of X-ray images of a webcam. Images acquired using industrial CT scanning.
A webcam is a video camera that feeds its image in real time to a computer or computer network. Unlike an IP camera (which uses a direct connection using ethernet or Wi-Fi), a webcam is generally connected by a USB cable, FireWire cable, or similar cable.
Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. The common use as a video camera for the World Wide Web gave the webcam its name. Other popular uses include security surveillance, computer vision, video broadcasting, and for recording social videos.
Webcams are known for their low manufacturing cost and flexibility,[1] making them the lowest cost form of videotelephony. They have also become a source of security and privacy issues, as some built-in webcams can be remotely activated via spyware.
History
See also: History of videotelephony
Early development
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]
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 serial 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.[5]
In 2010, Time Magazine named the QuickCam as one of the top computer devices of all time.[6]
Videoconferencing via computers already existed, and at the time 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 TV series Big Brother, launched four years later.[7]
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.
The term 'webcam' (a portmanteau) 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 US$100 in 2012, a Three-dimensional space webcam became available, producing videos and photos in 3D Anaglyph image
with a resolution up to 1280 x 480 pixels. Both sender and receiver of
the images must use 3D glasses to see the effect of three dimensional
image.[8]
Uses
Childcare webcast video monitoring
Childcare webcams can offer improved security, communication, and increased service value in daycare
facilities. According to researchers and industry leaders, as many as
100 childcare facilities add Internet viewing systems each month, and
the total number of centers with some form of Internet monitoring runs
into the thousands. In the United States, private services have been
offering dedicated webcasting systems to centers nationwide for several
years as of 2010.
Commerce
Webcams have been increasingly 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.[9]
Videocalling and videoconferencing
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. Video calling support has also been added to several popular instant messaging programs.
Video security
Webcams are also used as security cameras. Software is available to allow PC-connected cameras to watch for movement and sound,[10]
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,[11]
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.
Recently webcam privacy software has been introduced by such
companies such as Stop Being Watched or Webcamlock. 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.
In December 2011, Russia announced that 290,000 Webcams would be installed in 90,000 polling stations to monitor the Russian presidential election, 2012.[12]
Video clips and stills
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).
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 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, 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 are available as either standalone executables or inside web browser windows using Adobe Flash.
Astro photography
With the 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 panel instead of comparatively newer CMOS panels. The lens of the
cameras are removed and then these are attached to telescopes to record
images, video or still 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. Philips PCVC 740K, and SPC 900 are one of the few webcams
liked by astro photographers.
Technology
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 that can be screwed in and out to focus the camera. 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 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. Typically, each frame is transmitted uncompressed in RGB or YUV or compressed as JPEG. 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 without the need for proprietary device drivers. Microsoft Windows XP SP2, Linux[13] 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.[14] 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.[15] 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 sometimes only in video mode[citation needed].
It is not clear whether these indicators can be circumvented when
webcams are surreptitiously activated without the user's knowledge or
intent, via spyware.[citation needed]
In the field of computer security, camfecting
is the fraudulent process of attempting to hack into a person's webcam
and activate it without the webcam owner's permission. 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 search engine queries were published in an online forum[16] which allow anyone to find thousands of Panasonic- and Axis
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 viewable by 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.[17][18]
The school board involved quickly disabled their laptop spyware program
after parents filed lawsuits against the board and various individuals.[19][20]
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 Camgirling.
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.[21] In an 2013 case, the transmission of nude photos and videos via Omegle from a teenage girl to a schoolteacher resulted in a child pornography charge.[22]
YouTube is a popular website hosting many videos made using webcams. News websites such as the BBC also produce professional live news videos using webcams rather than traditional cameras.[23][citation needed]
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.[24] Webcam recordings of teenagers, including underage teenagers, are frequently posted on popular Web forums and imageboards such as 4chan.[25][26]
Descriptive names and terminology
Videophone calls (also: videocalls and video chat),[27] differ from videoconferencing in that they expect to serve individuals, not groups.[28] However that distinction has become 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.[29]
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.[30][31] 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 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, deaf Video Relay Service and tele-medical, diagnostic and rehabilitative
use or services. New services utilizing videocalling and
videoconferencing, such as teachers and psychologists conducting online
sessions,[32] 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.
The types of web-camera
There are many types of camera available for broadcasting images across the internet.
This section describes the different types and their suitability for use as a weather
web-camera. Described are USB webcams, Internet Protocol cameras, wireless cameras,
movable cameras, video servers and digital still cameras. This section also explains
why streaming video is unnecessary for weather web-cameras.
USB Webcams
The most popular web-cameras are USB webcams; which means they are web-cameras
that connect directly to a computer using a USB lead. These models are intended
for person-to-person communication using products like Netmeeting and Skype.
USB web-cameras are cheap and have wide angle lenses that make them ideal for use
as weather web-cameras. However, to function as a web-camera that can be viewed
across the internet, they must be connected to a computer which has both specialist
driver and web-casting software pre-installed. Furthermore, if a webcam is
to provide weather views all day long, then the computer will have to be switched
on all day too.
It is worth pointing out that USB webcams come with an
image capture button. For the button to function correctly, the webcam's driver
software must be installed and, the computer needs to know what to do with the
captured image; such as display it, save it, edit it.
PROS: Cheap and available in most stores.
CONS: Requires an always-on computer with software installed.
Stand alone Internet Protocol cameras
An Internet Protocol camera or IP camera is a web-camera that contains all
the parts required to function as a web-camera but, without the need to connect
it to a computer to make it work. Instead, the IP camera connects directly to a
router; the device for wiring up office and home networks. It can then communicates
directly over the internet by itself.
An IP camera features a built-in web server that allows the camera's images
to be viewed directly by anyone across the internet. Many IP cameras can also broadcast
or stream their output as live video over the internet; which is why IP cameras
are used for office and home surveillance. Also, most IP cameras can automatically
upload an image to another web site (using FTP) at regular intervals; a feature
which makes them ideal as switch on and forget weather web-camera service.
PROS: Ideal stand alone solution for a weather web-camera.
CONS: Very few!
The IP Camera Zoo
IP cameras come in all shapes, sizes and
specifications. Amidst the good, bad and plain ugly,
some are designed to sit on desks,
others to mount over doorways. There are those to mount in ceilings and
under eves. Some have high quality
optical zoom lenses and some have more than one lens. Many are wireless
and may come fitted with infrared LEDs.
Then there are IP cameras mounted in blast proof cases and
those small enough to fit into the palm
of the hand. And there are those that can remotely switch on other
devices and those with built-in
intercoms. Yet despite some considerable differences in specification
and
price, what they all have in common is
they can be viewed from anywhere across the internet.
When choosing an IP camera, you should consider what you want to use the camera for?
A
weather camera is a fixed
or movable (pan-and-tilt) device that
points above the horizon 24-7. Other than having the ability to
periodically
upload images to a custom web page,
there is no requirement for any other features. Security cameras
on-the-other-hand,
are designed for real-time monitoring;
which is why they include video streaming and alerting. Some security IP
cameras
can even be configured to push image
updates to social networks like Twitter, Flickr and Facebook. Some
cameras also
ship with Apps, allowing the IP camera to be controlled from anywhere using an I-Phone or Android Smartphone.
Most IP cameras sold today have security and monitoring features, which may include a
night vision mode. This is
achieved with a ring of infrared LEDs around the lens which, illuminates
the scene
after dark. Because web-camera detectors
are also sensitive to infrared light, the camera can covertly monitor a
scene
outside of the spectral range of human
vision. Results are viewed in grainy tones of green, white and black.
The LED's are
bright enough to monitor a room or entrance way but, for weather monitoring, this night vision mode is of no use!
A typical entry level specification would be: Fixed lens of average quality, VGA
resolution of 640 x 480 pixel images, fixed position, poor sensitivity in low light,
limited bandwidth when streaming, no on-image date and time. A typical high specification
device: High quality zoom lens with remote pan and tilt control, high sensitivity
in low light, more than one mega-pixel resolution, time stamping and live video
streaming with audio. All for around $100.
Wireless Internet Protocol cameras
Many IP cameras are wireless; which means they have the ability to connect
remotely to a network using a wireless access point, in the same way a
laptop computer does.
With a range of around 70 meters (200 feet), a Wi-Fi enabled web-camera
is a practical alternative to running long cables. However, although wireless when
it comes to their network aspect, wireless cameras still need a wired power
connection.
PROS: Ideal stand alone solution for a REMOTE weather web-camera.
CONS: Requires a Wi-Fi connection.
Pan and tilt cameras
Some budget IP cameras can be panned around or tilted up and down like a professional
CCTV camera. Some models can pan around 340 degrees and tilt up 60 degrees, which
is more than enough coverage for scanning the sky for the best weather phenomena.
Furthermore, many brands allow control of the web-camera remotely over the
internet using an ordinary web browser.
For maximum value, a movable weather web-camera will require a fairly high
and uninterrupted point-of-view of the horizon.
A caveat for allowing unrestricted public access to a movable web-camera; the web-camera
may be pointed in a direction that was never intended or worse, it could be maliciously
directed at the sun. A pan-and-tilt camera should only be steerable by it's owner.
A wireless Internet Protocol camera (left) and a conventional
USB webcam. Note the different lens diameters. The lens on the IP camera is about
7mm in diameter, whilst the lens on the USB webcam is the tiny red dot in the middle
of the lens shade, no more than 1.5mm across! Generally, the wider a lens, the more
sensitive a camera will be to low light levels. Also, the image quality in terms
of sharpness and colour saturation is improved.
Using analogue video cameras
It is possible to use a conventional analogue NTSC or PAL video camera as a web-camera.
The video camera can be anything from a miniature single board spycam, to
a full sized camcorder. Video cameras can be connected to a video capture card,
a piece of hardware installed inside a computer which captures images off
any video source. However, as with USB webcams, for a video camera to broadcast
images over the internet, software must be pre-installed on the capture computer
and, that computer that must remain switched on throughout the broadcast.
Alternatively, a video camera can be connected to a device called a Video Server.
A video server is a stand alone box that operates like a video capture card, converting
analogue video into digital images. Images are then either uploaded to a web site
(using the FTP protocol) or, served on request to web browsers anywhere on the internet
via the video server's built-in web server. Like IP cameras, video servers
connect directly to a network and therefore, do not require a dedicated computer
to make them work. Typically, video servers produce an image size that is a permutation
of 486 by 648 pixels for NTSC video sources and, 768 by 576 pixels for PAL.
PROS: Use cheap and discrete video cameras.
CONS: Video server may not be so easy to obtain.
Designed for the monitoring of CCTV systems over the web,
video servers will often have more than one video input; such as this model with
four inputs. For weather use, a number of angles can be covered simultaneously;
such as the north, south, west and east horizons!
Digital still cameras
A recent development in landscape and weather web-cameras is the use of digital
still cameras. These are conventional digital cameras that have been adapted for
web use with the addition of custom software.
The advantage that digital cameras have over their web-camera counterparts is mega-pixel
performance and, significant gains in colour and contrast rendition. However, due
to the nature of adapting a specific branded digital still camera plus, the need
to install bespoke software on another computer, means for now, adapted digital
cameras are only for the most dedicated techie.
PROS: Excellent image quality.
CONS: Bespoke software and technical support issues.
Light sensors
The eye inside the web-camera is either a CCD sensor (charge coupled device)
or, more commonly, a MOS sensor (metal oxide semiconductor). Both types of device
have a surface layer of light sensitive components which are arranged as tens of
thousands of pixels. Each pixel is masked to be sensitive to red,
green or blue light. Usually, there is a one to one relationship between the number
of pixels on the sensor and the dimensions of the outputed image; the more pixels,
the greater the image resolution.
CCD sensors are often found in high quality web-cameras and digital cameras. Not
only do they produce high quality images but, they will also produce a useable image
at low light levels; CCD based webcams are often adapted for astronomy work.
MOS devices are cheap to manufacture and consume less then one percent of the energy
of a CCD. However, they have poor light sensitivity and produce under-saturated
and grainy images in dim lighting conditions.
Generally, MOS based web-cameras are cheap, cheerful and made for good light applications;
such as a weather web-camera. CCD cameras are expensive and made for specialised
surveillance purposes.
Summary
- USB Webcams are cheap and easily available, but they require connecting to a computer,
can only be five meters from that computer and, the computer must have specialist
software and drivers pre-installed.
- Internet Protocol Web-cameras are an ideal stand alone solution. They connect to
the internet and serve images without the need for a computer.
- Wireless IP cameras have all of the benefits of the above, with the added bonus
of no network cabling.
- Video Servers offer an effective alternative to IP Cameras, as they can use any
kind of video camera.
- Still-digital cameras make very good weather web-cameras but, the technology is
immature.
- Pan and tilt cameras work best with an uninterrupted view.
Source :- http://en.wikipedia.org, http://meteo.milliflora.com/MET_Page_CamTypes.aspx,
Webcam
From Wikipedia, the free encyclopedia
|
Wikimedia Commons has media related to: Webcams |
Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. The common use as a video camera for the World Wide Web gave the webcam its name. Other popular uses include security surveillance, computer vision, video broadcasting, and for recording social videos.
Webcams are known for their low manufacturing cost and flexibility,[1] making them the lowest cost form of videotelephony. They have also become a source of security and privacy issues, as some built-in webcams can be remotely activated via spyware.
History
See also: History of videotelephony
Early development
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]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 serial 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.[5]In 2010, Time Magazine named the QuickCam as one of the top computer devices of all time.[6]
Videoconferencing via computers already existed, and at the time 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 TV series Big Brother, launched four years later.[7] 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.
The term 'webcam' (a portmanteau) 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 US$100 in 2012, a Three-dimensional space webcam became available, producing videos and photos in 3D Anaglyph image with a resolution up to 1280 x 480 pixels. Both sender and receiver of the images must use 3D glasses to see the effect of three dimensional image.[8]
Uses
Childcare webcast video monitoring
Childcare webcams can offer improved security, communication, and increased service value in daycare facilities. According to researchers and industry leaders, as many as 100 childcare facilities add Internet viewing systems each month, and the total number of centers with some form of Internet monitoring runs into the thousands. In the United States, private services have been offering dedicated webcasting systems to centers nationwide for several years as of 2010.Commerce
Webcams have been increasingly 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.[9]Videocalling and videoconferencing
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. Video calling support has also been added to several popular instant messaging programs.
Video security
Webcams are also used as security cameras. Software is available to allow PC-connected cameras to watch for movement and sound,[10] 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,[11] 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.Recently webcam privacy software has been introduced by such companies such as Stop Being Watched or Webcamlock. 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.
In December 2011, Russia announced that 290,000 Webcams would be installed in 90,000 polling stations to monitor the Russian presidential election, 2012.[12]
Video clips and stills
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).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 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, 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 are available as either standalone executables or inside web browser windows using Adobe Flash.
Astro photography
With the 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 panel instead of comparatively newer CMOS panels. The lens of the cameras are removed and then these are attached to telescopes to record images, video or still 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. Philips PCVC 740K, and SPC 900 are one of the few webcams liked by astro photographers.Technology
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 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. Typically, each frame is transmitted uncompressed in RGB or YUV or compressed as JPEG. 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 without the need for proprietary device drivers. Microsoft Windows XP SP2, Linux[13] 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.[14] 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.[15] 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 sometimes only in video mode[citation needed]. It is not clear whether these indicators can be circumvented when webcams are surreptitiously activated without the user's knowledge or intent, via spyware.[citation needed]In the field of computer security, camfecting is the fraudulent process of attempting to hack into a person's webcam and activate it without the webcam owner's permission. 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 search engine queries were published in an online forum[16] which allow anyone to find thousands of Panasonic- and Axis 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 viewable by 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.[17][18] The school board involved quickly disabled their laptop spyware program after parents filed lawsuits against the board and various individuals.[19][20]
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 Camgirling. 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.[21] In an 2013 case, the transmission of nude photos and videos via Omegle from a teenage girl to a schoolteacher resulted in a child pornography charge.[22]YouTube is a popular website hosting many videos made using webcams. News websites such as the BBC also produce professional live news videos using webcams rather than traditional cameras.[23][citation needed]
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.[24] Webcam recordings of teenagers, including underage teenagers, are frequently posted on popular Web forums and imageboards such as 4chan.[25][26]
Descriptive names and terminology
Videophone calls (also: videocalls and video chat),[27] differ from videoconferencing in that they expect to serve individuals, not groups.[28] However that distinction has become 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.[29]
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.[30][31] 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 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, deaf Video Relay Service and tele-medical, diagnostic and rehabilitative use or services. New services utilizing videocalling and videoconferencing, such as teachers and psychologists conducting online sessions,[32] 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.
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USB Webcams
PROS: Cheap and available in most stores. CONS: Requires an always-on computer with software installed. |
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Stand alone Internet Protocol cameras
PROS: Ideal stand alone solution for a weather web-camera. CONS: Very few! |
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The IP Camera Zoo
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Wireless Internet Protocol cameras
PROS: Ideal stand alone solution for a REMOTE weather web-camera. CONS: Requires a Wi-Fi connection. |
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Pan and tilt cameras
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A wireless Internet Protocol camera (left) and a conventional USB webcam. Note the different lens diameters. The lens on the IP camera is about 7mm in diameter, whilst the lens on the USB webcam is the tiny red dot in the middle of the lens shade, no more than 1.5mm across! Generally, the wider a lens, the more sensitive a camera will be to low light levels. Also, the image quality in terms of sharpness and colour saturation is improved. |
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Using analogue video cameras
PROS: Use cheap and discrete video cameras. CONS: Video server may not be so easy to obtain.
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Digital still cameras
A recent development in landscape and weather web-cameras is the use of digital
still cameras. These are conventional digital cameras that have been adapted for
web use with the addition of custom software.
The advantage that digital cameras have over their web-camera counterparts is mega-pixel performance and, significant gains in colour and contrast rendition. However, due to the nature of adapting a specific branded digital still camera plus, the need to install bespoke software on another computer, means for now, adapted digital cameras are only for the most dedicated techie. PROS: Excellent image quality. CONS: Bespoke software and technical support issues. |
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Light sensors
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Summary
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