Closed-circuit television, usually referred to as CCTV, is a number of video cameras used to transmit a signal to a particular place on a specific set of monitors.
The difference between CCTV and broadcast television is that in the case of CCTV the signal isn’t openly transmitted. However, it may use P2P or mesh wireless links. Despite the fact that almost any video camera can fit this definition, the term “CCTV” is usually applied to the cameras used for surveillance in areas that need attention – for example, banks, airports, casinos or convenience stores. While videotelephony isn’t often called so, the video used for distance education is usually called CCTV.
CCTV equipment is widely used in industrial plants, providing the opportunity to observe parts of a process from a central control room. This is especially convenient when the environment isn’t suitable for humans. Such systems may work continuously or at certain periods of time – to monitor a particular event, for instance. Meanwhile, there is a more advanced form of CCTV, which uses Digital Video Recorders (DVRs). It allows recording for many years, offering many quality and performance options and additional features, including motion detection and email alerts. Now decentralized IP-based CCTV cameras with megapixel sensors allow recording directly to either network-attached storage devices or internal flash, which means that they can operate in a stand-alone mode.
Surveillance of the public with the help of CCTV is common in many areas throughout the globe. The leader is the United Kingdom: according to the reports, there are more cameras per person in the UK than in any other country. However, the increasing use of CCTV has led to a debate about security versus privacy.
Closed-circuit television recording systems are still used at launch sites in order to record the flight of the rockets and find the possible causes of malfunctions. Meanwhile, larger rockets are usually equipped with CCTV cameras that send pictures of stage separation back to Earth by radio link. Siemens AG was first to install the CCTV system at Test Stand VII in Peenemünde, Germany 70 years ago to observe the launch of V-2 rockets. Walter Bruch, famous German engineer, developed design and installed the system.
As for the United States, the first commercial CCTV system was installed in the country 7 years later and was known as Vericon. Almost no information is available about Vericon except that it was advertised as the system which doesn’t require a government permit. Another appearance of CCTV was in 1973 in Times Square in New York City, where it was installed by the New York Police Department. The system was meant to deter crime occurring in the area, but crime rates didn’t drop much thanks to the cameras. Anyway, in the 1980s video surveillance started spreading across the United States particularly targeting public areas. CCTV was considered a cheaper way to deter crime than increasing a number of the police officers.
Businesses also started using video surveillance, particularly those prone to theft. Digital multiplexing in the 1990s allowed for a few cameras at once to record, along with introducing time lapse and motion only recording. This increased the use of the surveillance systems throughout the US, which was preferable to the old-style cameras because of both time and money saved. Since the mid-1990s, the police all over the US have been installing cameras in different public spaces, such as schools, housing projects and public parks departments. After the 9/11 attacks, the use of CCTV has become a common occurrence to deter terrorists.
CCTV can be used for various purposes, including crime prevention. For instance, the 2-year-old James Bulger was recorded by CCTV in the shopping centre being led away by his killers. Various experiments in the United Kingdom during the 1970s and 1980s, which included outdoor CCTV in Bournemouth in 1985, resulted in a few larger trial programs.
The government report titled “CCTV: Looking Out For You”, issued by the Home Office 18 years ago, proved the experiments successful and paved the way for an increase in the number of CCTV systems. Nowadays, systems cover almost all town and city centers, along with a lot of stations, car-parks and estates.
Another analysis by the University of Cambridge and Northeastern University, titled “Public Area CCTV and Crime Prevention: An Updated Systematic Review and Meta-Analysis”, investigated forty-four various studies which surveyed areas from the UK to US cities like Cincinnati and New York. The results of the analysis were the following.
Firstly, CCTV systems were most effective in parking lots, since their use led to a 51% decrease in crime. Secondly, public transportation areas enjoyed a 23% decrease in crimes. Finally, CCTV in public settings was the least effective (only a 7% decrease in crimes). However, if you sort by country, CCTV in the UK accounted for the majority of the drop, while the decrease in other areas was insignificant.
Meanwhile, some experts point out that the results from the above 2009 analysis conducted by Walsh and Farrington were controversial – the previous meta-analysis completed by them in 2002 showed the same: a considerable decrease in car park crime (40%) and an insignificant drop in crime in public transit and public places. The analysis in question was criticized for the inclusion of confounding variables (for example, notification of the cameras on site, enhanced street lighting) discovered in the studies analyzed. The factors in question couldn’t be teased apart from the effect of the surveillance cameras being present or absent during the crimes. In other words, there is almost always a combination of the factors responsible for the decrease in crime, not only the CCTV cameras. The latest study admitted to such problems and the ones with the consistency of the percentage of area covered by the cameras within the websites included into testing (for example, car parks had more cameras per square inch than public transit). Anyway, there is still a lot of research to be done in order to find out the effectiveness of such cameras on crime prevention.
There is evidence that cameras help in detection and conviction of offenders – the police forces routinely seek camera recordings after various crimes. In addition, CCTV has played an important role in tracking the movements of suspects or victims and is widely regarded by antiterrorist officers as a fundamental instrument in doing that. CCTV systems have also played a critical part in the defense against terrorism since the 1970s – they were installed on public transport in order to deter crime, as well as in mobile police surveillance vans, usually with automatic number plate recognition. In addition, a network of APNI-linked CCTV cameras now manages the UK capital’s congestion charging zone.
However, there’s still some political hostility to CCTV systems, and a number of commentators have downplayed the evidence of their effectiveness, particularly in the United States. Nevertheless, such assertions are just based on either poor methodology or imperfect comparisons, or both. As for the question of whether CCTV is cost-effective, this one is more open, because low-quality kits are cheap, but professional ones are very expensive.
There was a cost-benefit analysis of the surveillance systems in crime prevention, performed by Gill and Spring. It revealed little monetary saving with the installation of the cameras, because majority of the crimes prevented incurred little monetary loss. But they mentioned that advantages of non-monetary value can’t be reflected in a traditional cost-benefit analysis and therefore were omitted from their research. At the same time, if one wants to get a full understanding of the costs and benefits of the surveillance systems in crime prevention, they would have to include those factors. According to a 2008 report by British Police Chiefs, just 3% of crimes were solved by CCTV. For instance, in London, the police report revealed that only one crime was solved per 1000 installed cameras. Sometimes, CCTV cameras themselves were attacked.
Another example is July 22, 2005, when Jean Charles de Menezes was shot dead by the coppers at Stockwell tube station. His brother, Giovani Menezes, confirmed that the cameras proved he didn’t have suspicious behavior. The days before there were bombing attempts, so some of the tapes were believed to be removed from CCTV cameras for study, and the devices didn’t work. However, the experts hope that an ongoing change to DVR-based technology will stop similar problems from occurring in future.
An interesting project called “Internet Eyes” was announced in October 2009. It would pay members of the public to view the camera images and report any crimes they saw. The project aimed at adding “more eyes” to CCTV cameras that might be insufficiently monitored. However, civil liberties campaigners criticized this project as “a distasteful and a worrying development”.
Meanwhile, some CCTV cameras in the country are unknown, because there’s no requirement to register them. But the number of cameras in the United Kingdom, for instance, is estimated at 1.85 million, based on extrapolating from a comprehensive study of both public and private cameras. Of course, the density of cameras varies from region to region and actually makes this figure nearly meaningless. The same report says that the average person is seen by 70 cameras every day – mostly by cameras in shops.
Another report says that there are about 1.5 million cameras in city centers, stations, airports, and other locations, but this figure doesn’t include the smaller surveillance systems like those that might be found in local corner shops.
Another interesting fact: the hackers and guerrilla artists exposed the vulnerabilities of the CCTV systems by so-called “video sniffing”, crossing feeds, uploading their own video feeds and using the video footage for artistic purposes.
One more use of CCTV is supervision of the industrial processes which take place under conditions dangerous for humans. They include processes in the chemical industry, the interior of reactors and facilities for manufacture of nuclear fuel. The systems used for these purposes include line-scan and thermographic cameras that let operators measure the temperature.
Of course, cameras are used by traffic police to monitor traffic. Most of the cities and highways have extensive traffic-monitoring systems that help detect congestion and notice accidents. By the way, a lot of those cameras are owned by private entities and transmit data to drivers’ GPS systems.
For example, the London congestion charge is enforced by CCTV cameras located at the boundaries of and inside the congestion charge zone that automatically read the license plates of cars. In case the driver doesn’t pay the charge, he gets a fine. The same system is being developed to locate cars reported stolen. Finally, lots of CCTV systems are used as traffic enforcement cameras.
CCTV systems are also used in transport. They may be installed where an operator of a machine isn’t able to directly observe the passengers who may be injured by some unexpected machine operation. For instance, on a subway train, the cameras help the operator make sure that the passengers are clear of doors before closing them.
The CCTV systems are also useful for the operators of an amusement park ride – they help them make sure that people aren’t endangered when starting the ride. Indeed, a surveillance camera and dashboard monitor are able to make reversing a vehicle safer, because they allow the driver to see objects or people not otherwise visible.
Compared to the United Kingdom, the use of CCTV in the US is less common, but the practice is rapidly increasing, while generally meeting opposition. Within the last few years, the number of people in the United States who installed a CCTV system has increased dramatically. The modern CCTV market has shifted towards IP-based security products. As for Latin America, the CCTV market there is also developing rapidly along with the increase of property crime.
On the other hand, CCTV systems may be used by criminals – for instance, a hidden camera at an ATM can help them capture someone’s PIN without their knowledge. Such devices are usually small enough not to be noticed by people, and are located where they can monitor the keypad of the machine when a person enters their PIN. The video is transmitted wirelessly to the criminal.
So, why is there a strong opposition to the CCTV systems? They point out the loss of privacy of the citizens under surveillance, along with the negative impact of surveillance on civil liberties. In addition, they argue that the cameras displace crime instead of reducing it and call CCTV “Big Brother surveillance”, meaning George Orwell’s novel Nineteen Eighty-Four. If you don’t remember, it was telling about a two-way telescreen in every home through which The Party could monitor the people. Big Brother Watch, civil liberties campaign group, has even published a number of research papers into surveillance cameras. A couple years ago, they also released a report documenting council controlled CCTV systems.
In response, more positive views of such systems have argued that they aren’t intruding into people’s privacy, since they aren’t recording private, but only public space, where people’s right to privacy can reasonably be weighed against the possible advantages of surveillance. However, the US Supreme Court has held that there’s a right to privacy in public areas. Then, while there may be cases where your right to public privacy can be both reasonably and justifiably compromised, some people argue that they are too rare to not sufficiently warrant the constant compromising of public privacy rights which happens in areas with CCTV surveillance. For instance, they argue that CCTV surveillance is ethically permissible only in such rare situations as in areas with significant criminal threat. They point out that widespread camera surveillance jeopardizes both people’s liberty and dignity, saying that CCTV surveillance should be reserved for certain circumstances where it is undoubtedly beneficial.
Furthermore, there are some questions regarding unauthorized access to CCTV recordings. Back in 1998, the Data Protection Act in the UK put legal restrictions on the uses of camera recordings, as well as required their registration with the Data Protection Agency. 6 years later, the Information Commissioner’s Office clarified that this needed registration of all cameras with the Commissioner and prompt deletion of archived films. Nevertheless, show trial has limited the range of the protection provided by this legislation, and not all surveillance systems are now regulated. Under this law, private sector personnel in the country operating or monitoring surveillance systems are currently considered security guards and are subject to state licensing.
The 5-year-old report by the country’s Information Commissioner's Office emphasized the need for the public to become more aware of the increasing use of surveillance apparatus. The same year, the watchdog CameraWatch pointed out that the majority of surveillance cameras in the United Kingdom were operated illegally or violated privacy guidelines.
As for Canada, the use of CCTV systems there has grown rapidly. In Ontario, the municipal and provincial editions of the Freedom of Information and Protection of Privacy Act specify the guidelines controlling how images and data can be collected by that method and released.
Modern high-definition cameras feature a lot of computer-controlled technologies allowing them to identify, trace, and categorize objects. Video Content Analysis (VCA) is actually the capability of automatically analyzing video to capture and define temporal events which aren’t based on a single image. In other words, it can be regarded as the automated equivalent of the biological visual cortex.
Systems that employ VCA are able to recognize changes in the environment, identify and compare objects stored in the database by size, speed, and even color. One can program the camera’s actions based on what it sees – for instance, an alarm can start if a certain object has moved in a specified area, or if it is missing, or if someone has spray painted the lens.
Besides, VCA analytics can be used to detect various unusual patterns in a videos environment – the CCTV system can be set to reveal anomalies in a crowd, like a person moving in the opposite direction in airports in the area where passengers are only allowed to walk in one direction, or in a subway where people can’t exit through the entrances.
Another feature of VCA is that it can track people on a map by calculating their position from the images. After you linked several cameras, you can track a person through the entire building or area, which is useful for tracking a person without analyzing hours of film. Today the surveillance systems can’t easily identify people from video alone, but if you connect them to a key-card system, you will see the identities displayed as a tag over their heads on the film.
A difference in where the VCA technology is located is either the information is processed within the cameras or by a centralized server, because both technologies have their benefits and drawbacks.
The systems can also use facial recognition feature, which is a computer program for automatically identifying a person from a digital image or a video frame from a video source. This can be done by comparing facial features from the picture and a facial database.
CCTV and facial recognition were combined to be used for mass surveillance, but this proved ineffective due to the low discriminating power of facial recognition technology and the high number of false positives generated. Such systems were suggested to compare faces at airports and seaports with faces of suspected terrorists and criminals.
While computerized monitoring of images from the camera is under development, a human CCTV operator doesn’t have to be always looking at all screens, which allows him to monitor several CCTV cameras at once. Such systems don’t observe people directly, but rather trace their behavior by looking for specific types of body-movement behavior, clothing or baggage.
As it was said above, many people believe that the development of surveillance systems in public areas, which are connected to computer databases of faces, is a serious breach of civil rights. Critics say that you can’t meet anonymously in a public place now or drive and walk anonymously. Moreover, demonstrations in public places could also be affected by CCTV, because the authorities would be able to get the lists of people leading them, taking part, or just talking to them.
Major part of CCTV systems record and store video and images to a Digital Video Recorder: as for the IP cameras, just directly to a server, no matter on-site or offsite. Both the amount of information stored and the retention period of the content are subject to compression ratios, duration of image retention before being overwritten and so on.
The recordings are generally kept for a preset amount of time and then either archived or overwritten. The amount of time the videos are stored allows both retrieval and review in case a crime occurred or the data needs to be studied for other reasons.
There are networking CCTV cameras as well. For instance, the city of Chicago operates a networked CCTV system which combines government’s video feeds with feeds of the private sector, with the cameras installed in city buses, businesses, public schools, subway stations, and so on. Even home owners can contribute, and so the city incorporates the video feeds of a total of 15,000 cameras. It is used by the local Office of Emergency Management in the event of the emergency call: the system detects the location of the caller and displays the real-time video feed of the nearby camera without any user intervention. Although such system is far too vast to allow real-time monitoring, it can keep the video for later usage to be able to provide evidence in criminal cases.
Chicago is not the only city with such a system: London also has a network of CCTV cameras which allows to view and control them in real time mode. Different authorities, including the Metropolitan Police Service, Transport for London and other boroughs, can share the recorded images. The system uses a network protocol known as Television Network Protocol to provide access to more cameras than the individual system owner could run and maintain. The Glynn County Police Department employs a wireless mesh-networked system of portable battery-powered tripods for live surveillance and monitoring of police situations. Such systems could be used both on a stand-alone basis featuring secure communications to the nearest police laptops and in a larger mesh system having multiple tripods that feed video back to the command vehicle through wireless, and to police headquarters via 3G.
Integrated systems can allow you to connect remotely from the web and see what the cameras are viewing remotely, just as the IP cameras. Once, a woman from Florida saw her house get robbed and called police right from her office at work.
Today Internet Protocol (IP) cameras are very popular kind of CCTV devices. They use the Internet Protocol used by most Local Area Networks to transmit video across the networks in digital form. It can be transmitted through the public Internet, which allows users to view their camera via any broadband connection available via a PC or a 3G phone.
There is also such term as closed-circuit digital photography (CCDP), which is more suited for capturing and saving recorded high-resolution images, while CCTV is more suitable for live monitoring.
Nevertheless, CCTV systems are able to take high resolution images of the camera scene, for example on a time lapse or motion-detection basis. As for the images taken with a digital still camera, they usually have higher resolution than the pictures taken with video cameras. Low-cost high-resolution digital still cameras are more and more often used for CCTV purposes. You can monitor the images remotely if your PC is connected to the web.
Today a lot of people also choose wireless security cameras for home surveillance. They don’t require video cable for transmission, just a power cable, and they are very easy and inexpensive. While the previous generation of such cameras relied on analog technology, the modern ones use digital technology that allows for better audio and video, and a secure and interference-free signal.
More wireless cameras:
However, if CCTV cameras aren’t physically protected, they are vulnerable to many illegal tactics. For example, there are people who deliberately destroy cameras, so the devices can come with dust-tight, pressurized, explosion proof, and even bullet-resistant housings. If someone sprays something over the lens, it can make the image too blurry to be read. Lasers are also harmful for the cameras, as they can either blind or damage them. Nevertheless, most lasers are monochromatic, so color filters can help reduce the effect of laser pointers. Still, filters can also impair image quality and overall light sensitivity of the devices. Finally, complete protection from infrared, red, green, blue and UV lasers will need completely black filters, and this just renders the camera useless.
- See more at: http://www.wsystems.com/news/all-information-about-cctv-systems.html#sthash.xZb0fSxT.dpuf