Closed-circuit television

Surveillance cameras

Closed-circuit television (CCTV) is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors.

It differs from broadcast television in that the signal is not openly transmitted, though it may employ point to point (P2P), point to multipoint, or mesh wireless links. CCTV is often used for surveillance in areas that may need monitoring such as banks, casinos, airports, military installations, and convenience stores. It is also an important tool for distance education.[1][2]

In industrial plants, CCTV equipment may be used to observe parts of a process from a central control room, for example when the environment is not suitable for humans. CCTV systems may operate continuously or only as required to monitor a particular event. A more advanced form of CCTV, utilizing Digital Video Recorders (DVRs), provides recording for possibly many years, with a variety of quality and performance options and extra features (such as motion-detection and email alerts). More recently, decentralized IP-based CCTV cameras, some equipped with megapixel sensors, support recording directly to network-attached storage devices, or internal flash for completely stand-alone operation.

Surveillance of the public using CCTV is particularly common in the UK, where there are reportedly more cameras per person than in any other country in the world.[3] There and elsewhere, its increasing use has triggered a debate about security versus privacy.

Contents

History

Sign warning that premises are watched by CCTV cameras

The first CCTV system was installed by Siemens AG at Test Stand VII in Peenemünde, Germany in 1942, for observing the launch of V-2 rockets.[4] The noted German engineer Walter Bruch was responsible for the design and installation of the system.

CCTV recording systems are still often used at modern launch sites to record the flight of the rockets, in order to find the possible causes of malfunctions,[5][6] while larger rockets are often fitted with CCTV allowing pictures of stage separation to be transmitted back to earth by radio link.[7]

In September 1968, Olean, New York was the first city in the United States to install video cameras along its main business street in an effort to fight crime. The use of closed-circuit TV cameras piping images into the Olean Police Department propelled Olean to the forefront of crime-fighting technology.

The use of CCTV later on became very common in banks and stores to discourage theft, by recording evidence of criminal activity. Their use further popularised the concept. The first place to use CCTV in the United Kingdom was King's Lynn, Norfolk.[8]

In recent decades, especially with general crime fears growing in the 1990s and 2000s, public space use of surveillance cameras has taken off, especially in some countries such as the United Kingdom.

Uses

Crime prevention and prevalence in the UK

The two-year-old James Bulger being led away by his killers, recorded on shopping centre CCTV

Outside government special facilities, CCTV was developed initially as a means of increasing security in banks. Experiments in the UK during the 1970s and 1980s (including outdoor CCTV in Bournemouth in 1985), led to several larger trial programs later that decade.[8]

These were deemed successful in the government report "CCTV: Looking Out For You", issued by the Home Office in 1994, and paved the way for a massive increase in the number of CCTV systems installed. Today, systems cover most town and city centres, and many stations, car-parks and estates.

The exact number of CCTV cameras in the UK is not known but a 2002 working paper by Michael McCahill and Clive Norris of UrbanEye,[9] based on a small sample in Putney High Street, estimated the number of surveillance cameras in private premises in London is around 500,000 and the total number of cameras in the UK is around 4,200,000. Research conducted by the Scottish Centre for Crime and Justice Research and based on a survey of all Scottish local authorities, identified that there are over 2,200 public space CCTV cameras in Scotland.[10]

According to their estimate the UK has one camera for every 14 people, although it has been acknowledged that the methodology behind this figure is somewhat dubious.[11] The CCTV User Group estimate that there are around 1.5 million CCTV cameras in city centres, stations, airports, major retail areas and so forth. This figure does not include the smaller surveillance systems such as those that may be found in local corner shops.[12]

There is little evidence that CCTV deters crime; in fact, there is considerable evidence that it does not.[13] According to a Liberal Democrat analysis, in London "Police are no more likely to catch offenders in areas with hundreds of cameras than in those with hardly any."[14] A 2008 Report by UK Police Chiefs concluded that only 3% of crimes were solved by CCTV.[15] In London, a Metropolitan Police report showed that in 2008 only one crime was solved per 1000 cameras.[16]

Cameras have also been installed on public transport in the hope of deterring crime,[17][18] and in mobile police surveillance vans, often with automatic number plate recognition.[19] In some cases CCTV cameras have become a target of attacks themselves.[20]

On 22 July 2005, Jean Charles de Menezes was shot dead by police at Stockwell tube station. According to brother Giovani Menezes, "The film showed that Jean did not have suspicious behaviour" .[21]

Because of the bombing attempts the previous day, some of the tapes had been supposedly removed from CCTV cameras for study, and they were not functional.[22] An ongoing change to DVR based technology may in future stop similar problems occurring.[23]

The UK cameras were deployed and are maintained by NEP - Roll to Record, a division of NEP Broadcasting.[24]

In October 2009, an "Internet Eyes" website was announced which would pay members of the public to view CCTV camera images from their homes and report any crimes they witnessed. The site aimed to add "more eyes" to cameras which might be insufficiently monitored, but civil liberties campaigners criticised the idea as "a distasteful and a worrying development".[25]

Hacking and video art

Hackers and guerilla artists have exposed the vulnerabilities of the video systems in an act dubbed "video sniffing"[26][27] They have crossed feeds, uploaded their own video feeds and used the video footage for artistic purposes.

Industrial processes

Industrial processes that take place under conditions dangerous for humans are today often supervised by CCTV. These are mainly processes in the chemical industry, the interior of reactors or facilities for manufacture of nuclear fuel. Use of thermographic cameras allow operators to measure the temperature of the processes. The usage of CCTV in such processes is sometimes required by law.

Traffic monitoring

Many cities and motorway networks have extensive traffic-monitoring systems, using closed-circuit television to detect congestion and notice accidents. Many of these cameras however, are owned by private companies and transmit data to drivers' GPS systems.

The UK Highways Agency has a publicly owned CCTV network of over 1200 cameras covering the English motorway and trunk road network. These cameras are primarily used to monitor traffic conditions and are not used as speed cameras. With the addition of fixed camera for the Active Traffic Management system the number of cameras on the Highways Agency CCTV network is likely to increase significantly over the next few years.

The London congestion charge is enforced by cameras positioned at the boundaries of and inside the congestion charge zone, which automatically read the registration plates of cars. If the driver does not pay the charge then a fine will be imposed. Similar systems are being developed as a means of locating cars reported stolen.

Transport safety

Digital Video Recorder for Public Transport

A CCTV system may be installed where an operator of a machine cannot directly observe people who may be injured by unexpected machine operation. For example, on a subway train, CCTV cameras may allow the operator to confirm that people are clear of doors before closing them and starting the train.

Operators of an amusement park ride may use a CCTV system to observe that people are not endangered by starting the ride. A CCTV camera and dashboard monitor can make reversing a vehicle safer, if it allows the driver to observe objects or people not otherwise visible.

Outside the UK

Eric Harris and Dylan Klebold, during the Columbine High School Massacre

The use of CCTV in the United States is less common, though increasing, and generally meets stronger opposition. In 1998 3,000 CCTV systems were in use in New York City.[28] There are more than 10,000 CCTV systems in Chicago.[29]

In the last few years particularly, the percentage of people in the U.S having installed a security camera system has increased dramatically. Global Security Solutions with the help of Zone Tech Systems first announced the launch of IP surveillance in the US security industry by partnering up with Axis Communications (an IP pioneer). Today's CCTV market has transformed the shift towards IP-based security products and systems, and is often touted as an example of a disruptive technology that has had – and will continue to have – profound consequences for the electronic security industry as a whole.[30]

In Latin America, the CCTV market is growing rapidly with the increase of property crime.[31]

Criminal use

Criminals may use surveillance cameras, for example a hidden camera at an ATM to capture people's PINs without their knowledge. The devices are small enough not to be noticed, and are placed where they can monitor the keypad of the machine as people enter their PINs. Images may be transmitted wirelessly to the criminal.[32]

Privacy

A surveillance room
A mobile closed-circuit TV van monitoring a street market

Opponents of CCTV point out the loss of privacy of the people under surveillance, and the negative impact of surveillance on civil liberties. Furthermore, they argue that CCTV displaces crime, rather than reducing it. Critics often dub CCTV as "Big Brother surveillance", a reference to George Orwell's novel Nineteen Eighty-Four, which featured a two-way telescreen in every home through which The Party would monitor the populace.

More positive views of CCTV cameras have argued that the cameras are not intruding into people's privacy, as they are not surveilling private, but public space, where an individual's right to privacy can reasonably be weighed against the public's need for protection from presumptively innocent people .[33]

The recent growth of CCTV in housing areas also raises serious issues about the extent to which CCTV is being used as a social control measure rather than simply a deterrent to crime. However, since the September 11 attacks of 2001, many studies have suggested that public opinion of CCTV has grown more favorable. Many proponents of CCTV cite the attacks of the London Underground bombings as one example of how effective surveillance led to swift progress in post-event investigations.

Quite apart from government-permitted use (or abuse), questions are also raised about illegal access to CCTV recordings. The Data Protection Act 1998 in the United Kingdom led to legal restrictions on the uses of CCTV recordings, and also mandated their registration with the Data Protection Agency. In 2004, the successor to the Data Protection Agency, the Information Commissioner's Office clarified that this required registration of all CCTV systems with the Commissioner, and prompt deletion of archived recordings.

However subsequent case law (Durant vs. FSA) has limited the scope of the protection provided by this law, and not all CCTV systems are currently regulated.[34] Private sector personnel in the UK who operate or monitor CCTV devices or systems are now considered security guards and have been made subject to state licensing.

A 2007 report by the UK's Information Commissioner's Office, highlighted the need for the public to be made more aware of the "creeping encroachment" into their civil liberties created by the growing use of surveillance apparatus. A year prior to the report Richard Thomas, the Information Commissioner, warned that Britain was "sleepwalking into a surveillance society".

In 2007, the UK watchdog CameraWatch claimed that the majority of CCTV cameras in the UK are operated illegally or are in breach of privacy guidelines. In response, the Information Commissioner's Office denied the claim adding that any reported abuses of the Data Protection Act are swiftly investigated.[35]

In the United States, there are no such data protection mechanisms. It has been questioned whether CCTV evidence is allowable under the Fourth Amendment, which prohibits "unreasonable searches and seizures". The courts have generally not taken this view.

In Canada, the use of video surveillance has grown very rapidly. In Ontario, both the municipal and provincial versions of the Freedom of Information and Protection of Privacy Act [36] outline very specific guidelines that control how images and information can be gathered by this method and/or released.

Technological developments

Surveillance camera at London (Heathrow) Airport with a wiper for clear images during rain

Computerised monitoring

The first closed-circuit television cameras used in public spaces were crude, conspicuous, low definition black and white systems without the ability to zoom or pan. Modern CCTV cameras use small high definition colour cameras that can not only focus to resolve minute detail, but by linking the control of the cameras to a computer, objects can be tracked semi-automatically. The technology that enable this is often referred to as Video Content Analysis (VCA), and is currently being developed by a large number of technological companies around the world. The current technology enable the systems to recognize if a moving object is a walking person, a crawling person or a vehicle. It can also determine the color of the object. NEC claim to have a system that can identify a person's age by evaluating a picture of him/her. Other technologies claim to be able to identify people by their biometrics.

CCTV monitoring station run by the West Yorkshire Police at the Elland Road football ground in Leeds

The system identifies where a person is, how he is moving and whether he is a person or for instance a car. Based on this information the system developers implement features such as blurring faces or "virtual walls" that block the sight of a camera where it is not allowed to film. It is also possible to provide the system with rules, such as for example "sound the alarm whenever a person is walking close to that fence" or in a museum "set off an alarm if a painting is taken down from the wall".

VCA can also be used for forensics after the film has been made. It is then possible to search for certain actions within the recorded video. For example if you know a criminal is driving a yellow car, you can set the system to search for yellow cars and the system will provide you with a list of all the times where there is a yellow car visible in the picture. These conditions can be made more precise by searching for "a person moving around in a certain area for a suspicious amount of time", for example if someone is standing around an ATM machine without using it.

Surveillance camera outside a McDonalds highway drive-in

Maintenance of CCTV systems is important in case forensic examination is necessary after a crime has been committed.

In crowds the system is limited to finding anomalies, for instance a person moving in the opposite direction to the crowd, which might be a case in airports where passengers are only supposed to walk in one direction out of a plane, or in a subway where people are not supposed to exit through the entrances.

VCA also has the ability to track people on a map by calculating their position from the images. It is then possible to link many cameras and track a person through an entire building or area. This can allow a person to be followed without having to analyze many hours of film. Currently the cameras have difficulty identifying individuals from video alone, but if connected to a key-card system, identities can be established and displayed as a tag over their heads on the video.

Monitoring station of a small office building

There is also a significant difference in where the VCA technology is placed, either the data is being processed within the cameras (on the edge) or by a centralized server. Both technologies have their pros and cons.

The implementation of automatic number plate recognition produces a potential source of information on the location of persons or groups.

There is no technological limitation preventing a network of such cameras from tracking the movement of individuals. Reports have also been made of plate recognition misreading numbers leading to the billing of the entirely wrong person.[37] In the UK, car cloning is a crime where, by altering, defacing or replacing their number plates with stolen ones, perpetrators attempt to avoid speeding and congestion charge fines and even to steal petrol from garage forecourts.

CCTV critics see the most disturbing extension to this technology as the recognition of faces from high-definition CCTV images. This could determine a person's identity without alerting him that his identity is being checked and logged. The systems can check many thousands of faces in a database in under a second.

The combination of CCTV and facial recognition has been tried as a form of mass surveillance, but has been ineffective because of the low discriminating power of facial recognition technology and the very high number of false positives generated. This type of system has been proposed to compare faces at airports and seaports with those of suspected terrorists or other undesirable entrants.

Eye-in-the-sky surveillance dome camera watching from a high steel pole

Computerized monitoring of CCTV images is under development, so that a human CCTV operator does not have to endlessly look at all the screens, allowing an operator to observe many more CCTV cameras. These systems do not observe people directly. Instead they track their behaviour by looking for particular types of body movement behavior, or particular types of clothing or baggage.

The theory behind this is that in public spaces people behave in predictable ways. People who are not part of the 'crowd', for example car thieves, do not behave in the same way. The computer can identify their movements, and alert the operator that they are acting out of the ordinary. Recently in the latter part of 2006, news reports on UK television brought to light newly developed technology that uses microphones in conjunction with CCTV.

If a person is observed to be shouting in an aggressive manner (e.g., provoking a fight), the camera can automatically zoom in and pinpoint the individual and alert a camera operator. Of course this then lead to the discussion that the technology can also be used to eavesdrop and record private conversations from a reasonable distance (e.g., 100 metres or about 330 feet).

The same type of system can track identified individuals as they move through the area covered by CCTV. Such applications have been introduced in the early 2000s, mainly in the USA, France, Israel and Australia. With software tools, the system is able to develop three-dimensional models of an area, and to track and monitor the movement of objects within it.

To many, the development of CCTV in public areas, linked to computer databases of people's pictures and identity, presents a serious breach of civil liberties. Critics fear the possibility that one would not be able to meet anonymously in a public place or drive and walk anonymously around a city. Demonstrations or assemblies in public places could be affected as the state would be able to collate lists of those leading them, taking part, or even just talking with protesters in the street.

Retention, storage and preservation

The long-term storage and archiving of CCTV recordings is an issue of concern in the implementation of a CCTV system. Re-usable media such as tape may be cycled through the recording process at regular intervals. There are statutory limits on retention of data.

Recordings are kept for several purposes. Firstly, the primary purpose for which they were created (e.g. to monitor a facility). Secondly, they need to be preserved for a reasonable amount of time to recover any evidence of other important activity they might document (e.g. a group of people passing a facility the night a crime was committed). Finally, the recordings may be evaluated for historical, research or other long-term information of value they may contain (e.g. samples kept to help understand trends for a business or community).

Recordings are more commonly stored using hard disk drives in lieu of video cassette recorders. The quality of digital recordings are subject to compression ratios, images stored per second, image size and duration of image retention before being overwritten. Different vendors of digital video recorders use different compression standards and varying compression ratios.

Closed-circuit digital photography (CCDP)

A development in the world of CCTV (October 2005) is in the use of megapixel digital still cameras that can take 1600 x 1200 pixel resolution images of the camera scene either on a time lapse or motion detection basis. Images taken with a digital still camera have higher resolution than those taken with a typical video camera. Relatively low-cost digital still cameras can be used for CCTV purposes, using CCDP software that controls the camera from the PC.

Images of the camera scene are transferred automatically to a computer every few seconds. Images may be monitored remotely if the computer is connected to a network.

Combinations of PIR activated floodlights with 1.3Mpix and better digital cameras are now appearing. They save the images to a flash memory card which is inserted into a slot on the device. The flash card can be removed for viewing on a computer if ever an incident happens. They are not intended for live viewing, but are a very simple and cheap "install and forget" approach to this issue.

Closed-circuit digital photography (CCDP) is more suited for capturing and saving recorded photographs, whereas closed-circuit television (CCTV) is more suitable for live monitoring purposes.

IP cameras

Easy Connect Wireless IP camera

A growing branch in CCTV is internet protocol cameras (IP cameras). IP Cameras use the IP protocol, used by most LANs to transmit video across data networks in digital form. As it's IP, video can also, but not necessarily, be transmitted across the public Internet, which allow homeowners and businesses to view their camera(s) through any internet connection available through a computer or a 3G phone. For professional or public infrastructure applications, IP video would always be restricted to within a private network or VPN.[38]

Internet protocol is a protocol used for communicating data across a packet-switched network using the internet protocol suite, also referred to as TCP/IP.

Potential advantages

The following are potential advantages of IP cameras over traditional cameras:

Potential disadvantages

Potential weaknesses of IP cameras in comparison to other CCTV cameras include:

Networking CCTV cameras

The city of Chicago operates a networked video surveillance system which combines CCTV video feeds of government agencies with these of the private sector, installed in city buses, businesses, public schools, subway stations, housing projects etc. Even home owners are able to contribute footage. It is estimated to incorporate the video feeds of a total of 15,000 cameras.

The system is used by Chicago's Office of Emergency Management in case of an emergency call: it detects the caller's location and instantly displays the real-time video feed of the nearest security camera to the operator, not requiring any user intervention. While the system is far too vast to allow complete real-time monitoring, it stores the video data for later usage in order to provide possible evidence in criminal cases.[43]

London also has a network of CCTV systems that allows multiple authorities to view and control CCTV cameras in real time. The system allows authorities including the Metropolitan Police Service, Transport for London and a number of London boroughs to share CCTV images between them. It uses a network protocol called Television Network Protocol to allow access to many more cameras than each individual system owner could afford to run and maintain.

The Glynn County Police Department uses a wireless mesh networked system of portable battery-powered tripods for live megapixel video surveillance and central monitoring of tactical police situations. The systems can be used either on a stand-alone basis with secure communications to nearby police laptops, or within a larger mesh system with multiple tripods feeding video back to the command vehicle via wireless, and to police headquarters via 3G.

Integrated Systems

An integrated systems unit.

Integrated Systems allow users to connect remotely from the internet and view what their cameras are viewing remotely, similar to that of IP cameras. In one incident, a lady from Boynton Beach, Florida was able to watch her house get robbed and contacted police directly from her office at work.[44]

CCTV countermeasures

Unless physically protected, CCTV cameras have been found to be vulnerable against a variety of (mostly illegal) tactics:

See also

  • Bugging
  • Closed-circuit television camera
  • Documentary practice
  • Eye in the sky (camera)
  • Fake security camera
  • Information Awareness Office
  • IP camera
  • Physical security
  • Police
  • Privacy International
  • Proprietary DVR
  • Security Operations Center
  • Security smoke
  • Sousveillance (inverse surveillance)
  • Surveillance
  • Telescreen
  • The Convention on Modern Liberty
  • TV Network Protocol
  • Video analytics
  • Videotelephony

References

  1. ↑ Verman, Romesh. Distance Education In Technological Age, Anmol Publications Pvt. Ltd., 2005, pp.166, ISBN 8126122102, ISBN 9788126122103.
  2. ↑ "Distance education in Asia and the Pacific: Proceedings Of The Regional Seminar On Distance Education, 26 November - 3 December 1986", Asian Development Bank, Bangkok, Thailand, Volume 2, 1987
  3. ↑ Lewis, Paul. "Every step you take: UK underground centre that is spy capital of the world", The Guardian, March 2, 2009.
  4. ↑ Dornberger, Walter: V-2, Ballantine Books 1954, ASIN: B000P6L1ES, page 14.
  5. ↑ "ET_SRB Cam FS.indd" (PDF). http://www.nasa.gov/centers/marshall/pdf/114016main_ET_SRB_Cam_FS.pdf. Retrieved 2009-07-22. 
  6. ↑ "Ecliptic Enterprises Corporation". Eclipticenterprises.com. http://www.eclipticenterprises.com/products_rocketcam_avs.php. Retrieved 2009-05-08. 
  7. ↑ Brent D. Johnson. "Cameras Monitor Rocket Launch". Photonics.com. http://www.photonics.com/content/spectra/2003/January/applications/65734.aspx. Retrieved 2009-05-08. 
  8. ↑ 8.0 8.1 Staff (August 2007). "CCTV". Borough Council of King's Lynn & West Norfolk. http://www.west-norfolk.gov.uk/default.aspx?page=21697. Retrieved 2008-12-14. 
  9. ↑ "CCTV in London" (PDF). http://www.urbaneye.net/results/ue_wp6.pdf. Retrieved 2009-07-22. 
  10. ↑ Bannister, J., Mackenzie, S. and Norris, P. Public Space CCTV in Scotland(2009), Scottish Centre for Crime and Justice Research (Research Report)
  11. ↑ "FactCheck: how many CCTV cameras? - Channel 4 News". Channel4.com. http://www.channel4.com/news/articles/society/factcheck+how+many+cctv+cameras/2291167. Retrieved 2009-05-08. 
  12. ↑ "How many cameras are there?". CCTV User Group. 2008-06-18. http://www.cctvusergroup.com/art.php?art=94. Retrieved 2009-05-08. 
  13. ↑ Baram, Marcus (2007-07-09). "Eye on the City: Do Cameras Reduce Crime?". ABC News. http://www.abcnews.go.com/US/Story?id=3360287&page=1. Retrieved 2007-07-10. 
  14. ↑ "Tens of thousands of CCTV cameras, yet 80% of crime unsolved" by Justin Davenport 2007
  15. ↑ "Are CCTV cameras a waste of money in the fight against crime?" The Independent, 7 May 2008
  16. ↑ Hughe, Mark (25 August 2009). "CCTV in the spotlight: one crime solved for every 1,000 cameras". Independent News and Media Limited. http://www.independent.co.uk/news/uk/crime/cctv-in-the-spotlight-one-crime-solved-for-every-1000-cameras-1776774.html. Retrieved 2009-08-27. 
  17. ↑ "CCTV to drive down cab attacks," BBC
  18. ↑ Taxi CCTV cameras are installed," BBC
  19. ↑ CCTV patrols to monitor estates," BBC
  20. ↑ "http://news.bbc.co.uk/," BBC
  21. ↑ "Menezes family view CCTV footage," BBC
  22. ↑ "Menezes Death 'Cover-Up' Doubted," BBC
  23. ↑ "Digital CCTV Scheme Switches On," BBC
  24. ↑ "NEP Broadcasting, LLC NEP Europe - NEP Visions - NEP Roll to Record". Guardian.nepinc.com. http://guardian.nepinc.com/nepEurope.php. Retrieved 2009-05-08. 
  25. ↑ Public to Monitor CCTV From Home, BBC
  26. ↑ Christopher Werth To Watch the Watchers October 20, 2008 Newsweek
  27. ↑ Newsweek
  28. ↑ "You're Being Watched, New York!," 11 March 2002 BBC
  29. ↑ "Chicago Links Police, Private Cameras". WLS-TV. 2010. http://abclocal.go.com/wls/story?section=news/local&id=7370352. Retrieved 2010-08-16. 
  30. ↑ "Tulsa!," 11 March 2009 GSS
  31. ↑ "Latin American Physical Security Market Growing Rapidly," 8 October 2009 Security Magazine
  32. ↑ "ATM Security". Dedham Savings. http://www.dedhamsavings.com/index.php?option=com_content&task=view&id=83. Retrieved 2009-04-18. 
  33. ↑ Smile, the cameras are here to watch over you - The New Zealand Herald, Tuesday 18 March 2008, Page A14
  34. ↑ "Information Commissioner's Office". Informationcommissioner.gov.uk. http://www.informationcommissioner.gov.uk/eventual.aspx?id=5739. Retrieved 2009-05-08. 
  35. ↑ Majority of UK's CCTV cameras 'are illegal' Telegraph.co.uk
  36. ↑ Freedom of Information and Protection of Privacy Act Text
  37. ↑ "Congestion Charge Car '200 Miles Away'". BBC News. 2003-03-19. http://news.bbc.co.uk/1/hi/england/2865949.stm. Retrieved 2009-05-08. 
  38. ↑ "Some IP Cameras Can Be Remotely Monitored With An iPhone And Other Compatible 3G Devices" (PDF). http://www.lorexcorp.com/uploads/LNE3003%20-%20Release.pdf. Retrieved 2009-07-22. 
  39. ↑ "Advanced Remote Viewing Options on Lorex IP Cameras". Focusoncctv.lorextechnology.com. http://focusoncctv.lorextechnology.com/pdfs/LNE1001_Specs_R1.pdf. Retrieved 2009-10-28. 
  40. ↑ "Total Cost of Ownership study, Axis Communications". http://www.axis.com/corporate/corp/papers/tco.htm. Retrieved 2008-02-28. 
  41. ↑ "Lorex camera's features and spec. to show how advanced IP cameras are now becoming". Focusoncctv.lorextechnology.com. http://focusoncctv.lorextechnology.com/product.aspx?id=1965&nav=0. Retrieved 2009-05-08. 
  42. ↑ Network bandwidth and video storage space calculation by JVSG, January 17, 2008
  43. ↑ "Chicago's Camera Network Is Everywhere", The Wall Street Journal
  44. ↑ By Kim Segal CNN (2009-04-10). "How IP Cameras can help protect your home. Real CNN report". Cnn.com. http://www.cnn.com/2009/CRIME/04/10/webcam.home.invasion/index.html#cnnSTCVideo. Retrieved 2009-05-08. 

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