A surveillance camera is a permanently mounted, often motorized swiveling photo or video camera that is used to monitor an object or an area . The image from the surveillance camera can be displayed immediately on a monitor and recorded for later evaluation. Digital surveillance cameras can also generate still images. A very well-known use of these cameras is for the detection of violations in road traffic, such as driving at excessive speed .
The surveillance camera in the housing for outdoor use and wall bracket has also become a symbol for surveillance measures of all kinds.
Surveillance cameras are for example in banks or supermarkets for the prevention of shoplifting serve and at key buildings such as embassies used for monitoring. Other typical areas of application are train stations (especially the subway ) and airports or traffic monitoring , for example at highly frequented intersections. Dome cameras are mostly used in local public transport .
Video surveillance is used in other areas as well as deterring and investigating criminal offenses and the position of the perpetrators. Another application is the early detection of forest fires, for which cameras are installed on towers in areas at risk of fire, which can also be used as observation or radio towers. Thermal imaging cameras are also used here, as they can detect a possible fire more quickly.
Baby monitors are increasingly being equipped with a video option or replaced by video cameras. This type of indoor surveillance is also used when observing pets or when caring for people in need of care . The people to be looked after or pets can be observed without parents, pet owners or caregivers having to be in the same room. Wildlife observation is based on the same principle, in which animals can be observed in their natural environment without visibly invading their lives. Thermal imaging cameras are also used for animal observation.
Video surveillance is also used in research. Functions such as motion detection or the use of long-term recorders make video surveillance possible over a long period of time. Motion detection only records when an event occurs. This function saves a lot of time during the image evaluation when finding relevant events and reduces the storage space required to save the recordings.
In addition to the typical surveillance of people and animals, surveillance cameras are used to control and observe industrial processes and experiments, to make areas that are difficult to access visible (e.g. within a machine) or to control processes under conditions that are harmful to humans.
In automated processes in companies, video cameras are used to check what is happening. They record up to 24 hours a day as needed. In the event of a process stop or errors that have occurred, the course of the process can be quickly traced and the causes can be found. In factories, surveillance cameras are used for outside areas, so that they are optimally protected from moisture and mechanical stress.
Most of the surveillance cameras in the world are installed in the UK. Because of the James Bulger case, in particular , the country has a positive attitude towards video surveillance. The UK media falsely claimed that video footage led to the investigation.
In Austria, the number of surveillance cameras has risen to one million by 2013, where, according to ORF, over 160,000 surveillance cameras were registered in public places and in shopping centers.
In Germany, statistics were carried out in 2014 by the EHI Retail Institute , which asked about the use of CCTV in retail. Only 9.4% of the retailers surveyed stated that they did not use or plan to use video surveillance.
For the controversies surrounding the use of surveillance cameras in public spaces, see also:
The discussion about video surveillance has also led to the inclusion of surveillance cameras in art objects that deal with the issue.
Around 1980 the first surveillance camera systems were installed in self-service shops in Austria. Among them was the particularly conspicuous variant of the gondolas rotating 360 ° back and forth with several lens tubes and a clearly recognizable red flashing light. It can be assumed that there was usually only a camera behind a tube. The camera prices were high back then, and the images also want to be evaluated live via a workstation with numerous screens. Each gondola hung over a corridor between the rows of shelves on a tube from the ceiling, was a little flatter than hemispherical, all around radially outwards and a little downwards, about 5 camera tubes could be seen. The flashing light stood in front of the south pole of the sphere as a small dome and could be seen from all around at all times.
Surveillance cameras usually consist of the following (structural) parts:
- CCD or CMOS sensor chip
- Housing with heating and / or cooling and power supply
- possibly a servo mount
Monitors and recorders are used for signal processing. Surveillance cameras are rarely coupled with motion sensors ; Corresponding recorders (or software) often use the signals from the cameras themselves as motion sensors.
The quality of the generated image is determined by the CCD or CMOS chip used and the lens, whereby different lenses can be mounted on a camera depending on the area of application. New models of surveillance cameras use HD-SDI and present images in 720p or 1080p. They are sent to an HD-SDI recorder. Video cables can be up to 150 meters long.
Black-and-white and color cameras are used as required: black-and-white cameras are more sensitive to light and better suited for night use, while color cameras, on the other hand, offer the human observer a much faster image. Some color cameras are able to switch to black and white operation in the dark. The end user can already purchase cameras with a sensitivity of 0.01 lux from wholesalers .
The housings of cameras that are used indoors are often designed to be conspicuous, as video surveillance is usually intended to prevent deliberate criminal offenses. Often, opaque domes hide the direction of the camera from the human observer. This corresponds to the principle of using one-way mirrors in supermarkets. The dome also serves to physically protect the camera.
On the other hand, caution is advised with secret video surveillance. Especially in publicly accessible places and places, but also in private settings , this is not compatible with data protection or only under certain conditions . As soon as a surveillance system records image material and thus processes data of identifiable persons, there is a reportable data application.
Areas of application and tasks determine the design of the surveillance camera. If public places or an open company premises are to be observed, so-called obvious, i.e. visible cameras are ideal. Two types of construction are predominant in public: on the one hand the camera with a wall bracket, on the other hand the dome camera. These can either be fixed or mechanically movable ( PTZ ). In contrast, camouflaged (mini) cameras are suitable for detective measures.
Surveillance cameras with wall brackets
These cameras are mostly found in public places, in parks and on buildings of, for example, department store chains. They belong to the obvious cameras and, in addition to the timely detection of criminal offenses, also serve as a deterrent for casual offenders. Due to their mostly cubic shape, it is easy to see where the permanently mounted camera is pointing or which area it is monitoring. The area that it is not currently scanning is unprotected or requires an additional camera.
Dome cameras can be recognized by the semicircular housing. They can be found at the entrances of parking garages, in supermarkets or in local public transport. They are mostly attached to the ceiling and have tinted glass. Due to its circular design and the dark-tinted windows, it is not immediately possible to see which area is being monitored by the camera. It thus offers a higher deterrent factor than the wall-mounted camera. This is why dome cameras are also used in socially disadvantaged areas outdoors. For this task they are given a weatherproof outer housing, which is usually made of aluminum. In addition to the permanently installed dome cameras, there are also so-called speed dome cameras. With these, the actual camera inside can be panned and tilted from a distance and thus monitor a much larger area.
PTZ and controllable cameras
Controllable cameras can move up and down and sideways. This function is called PTZ , where the "P" stands for English. pan 'pan' and the 'T ' stands for tilt 'incline'. The "Z" indicates that these cameras also have a zoom function. You can capture stationary or moving objects and enlarge image sections for better identification. Cameras of this design, which are located in the higher price range, have the auto-tracking function. This records a person and follows them for as long as possible. PTZ cameras are used for live surveillance. Crimes can be detected quickly at airports or in stadiums so that security personnel can intervene promptly. The PTZ function has advantages and disadvantages: Thanks to its pan and tilt technology, you can scan a large area. On the other hand, the area that you are not currently examining is unprotected.
Mini cameras are very small cameras that are not easy to see with the naked eye. They belong to the non-obvious types and are primarily used for covert video surveillance. They can be used free-standing or placed in other objects such as smoke detectors , ballpoint pens or alarm clocks.
With the camouflaged camera, the camera is permanently installed with its object. The case, such as a wall clock, can still have its actual function (here: the time display). Camouflaged surveillance cameras are usually equipped with motion detectors so that they are only activated when an object intrudes into their detection area. In South Korea , the installation of hidden cameras in everyday objects such as hairdryers in hotels or public toilets has spread since around 2010. The phenomenon is called Molka in Korean and resulted in several thousand advertisements per year.
IP cameras are available in LAN and WLAN versions. This means that you can send the camera signals into the network either via a network cable or wirelessly via the WLAN. IP cameras have the advantage that they do not have to be connected to a computer. Instead, the image material can be accessed by any number of users on the appropriately configured end devices. Some models also have motion detection and an additional alarm function, which the user can use to change the camera image. B. is notified via an email. Furthermore, a distinction is made between outdoor and indoor IP cameras, the former being weatherproof.
Night vision cameras illuminate the area to be monitored with residual light amplifiers or record what is happening in thermal images.
Most night vision or infrared cameras use something called active infrared to create night vision. The camera is sensitive to near IR, which is not perceived by humans. An IR spotlight or LEDs attached to the camera itself serve as lighting. At first glance, the image of the camera on the monitor cannot be distinguished from that of a black-and-white camera illuminated by headlights. Many wildlife cameras have infrared LEDs.
In complete darkness, IR night vision cameras can still cover an area of 4 to 100 meters, provided that the appropriate illumination is guaranteed.
The quality of such a camera depends on several factors. Some have a low residual light intensity and are only suitable for close-up areas of up to 3 meters. In addition, color noise and color falsifications can occur during the transition from day and night lighting . For example, black clothing can appear light during the day when the fabric reflects near IR. Other models have a separate night vision technology. It automatically changes from day to night mode. Color noise cannot arise because night mode does without the color mode. IR-corrected lenses also compensate for the deviating wavelength between the day and night functions, so that there are hardly any blurred images.
Thermal imaging cameras
While an IR camera produces black and white images during night operation, the thermal imager uses the radiation from body heat that every object in the world possesses to generate the surveillance image (thermal image). If there are only slight temperature differences in the area under consideration, the temperature profile is difficult to perceive for the human eye. In order to increase the contrast, false colors are therefore mostly used when creating the thermal images. The image processing software translates the different shades of gray into yellow, red, blue and green areas. Red stands for high body heat and yellow for lower; Blue and green indicate the lowest body heat. Black areas do not emit any sensible body heat.
With the help of thermal imaging cameras, sources of fire can be identified at an early stage. They are also used for the early detection of forest fires.
Thermal imaging cameras are used in places where there is complete darkness or very difficult lighting conditions. Since they only produce thermal images, they cannot be used to identify people. However, an event is recognized as such in a manned video surveillance with thermal imaging cameras. Perpetrators can be found quickly by radiating their own body heat and caught by the security personnel in a timely manner.
Cons and Limitations
Reasons that speak against the use of thermal imaging cameras or residual light amplifiers for monitoring purposes:
- Residual light intensifiers and especially thermal imaging cameras are expensive. They provide reduced-color or falsified images.
- In property protection , it is assumed that the intensive lighting of areas has a deterrent effect on potential intruders. Continuous lighting enables the use of inexpensive color cameras with better image quality.
- In urban areas, the scattered light at night often enables the use of conventional surveillance cameras.
Conventional black and white cameras also contain CCD chips, which have a certain sensitivity to near infrared (color cameras or their lenses, on the other hand, have to filter out this area in order to avoid corruption). Infrared LEDs and headlights with appropriate filters can serve as a light source for every CCD black and white camera and thus enable night vision. In order to prevent the camera from being dazzled by reflections of the infrared light in the glass cover of the camera housing, IR headlights are preferably mounted separately from the camera.
Surveillance installations with IR spotlights can easily be seen by third parties with a (near) infrared viewing device. Many digital cameras (like the ones in cell phones) do not have an infrared filter either .
IR lighting is only really useful if conventional lighting is too weak or not available all night. Outside monitoring of objects Night Vision techniques are used primarily for observation of nocturnal animals (see Wild camera ).
Standards and regulations in Germany
For surveillance cameras (and their housings) valid standards or regulations within Germany are the protection class and the accident prevention regulations for cash registers, which define whether a camera can be intended for indoor or outdoor use or for use in banks.
When installing a surveillance camera or webcam that is aimed at a publicly accessible location, Federal Data Protection Act (BDSG) must be observed in Germany . This essentially regulates that no image or sound recordings may be made on which people can be identified. This also applies to features such as license plates, which enable identification. Violations of the BDSG can also be punished with imprisonment, depending on the severity.
BDSG does not apply to the processing of image and sound recordings for the protection of the state, public security, national defense and activities of the state in the field of criminal law.
In the private sector , video surveillance and storage (e.g. using surveillance cameras on and in residential buildings) is only permitted if the group of people directly affected (e.g. all tenants) have agreed to this measure. Otherwise, this constitutes a violation of the general personality rights of the person concerned, which can always justify a civil law claim for injunctive relief and in individual cases even claims for pain and suffering and damages ( BGB ).
- Working document on the subject of processing personal data from video surveillance ( Memento of March 5, 2005 in the Internet Archive ) (PDF file)
- Surveillance of Public Life (CCC) ( Memento of February 12, 2003 in the Internet Archive )
- Video surveillance in Europe Summary of the final report of a ZTG research project on video surveillance in Europe (2007; PDF file; 198 kB)
- Video surveillance using the example of London: between security madness and surveillance paranoia
- Fraunhofer Institute for Laser Technology ILT - High-Speed Process Monitoring ( Memento from December 13, 2013 in the Internet Archive ). Fraunhofer Institute for Laser Technology ILT. Retrieved December 11, 2013.
- Dietmar Kammerer: Pictures of the surveillance . edition suhrkamp, Frankfurt am Main 2008, ISBN 3-518-12550-8 .
- Under surveillance: more and more surveillance cameras. In: vbgv1.orf.at. ORF , January 25, 2006, accessed on September 15, 2017 .
- Private video surveillance on the rise. In: wien.orf.at. ORF, April 23, 2013, accessed on September 15, 2017 .
- Video surveillance systems (CCTV) in retail 2014. Whitepaper. In: axis.com. Retrieved October 17, 2017 (Prepared by the EHI Retail Institute on behalf of Axis Communications).
- Video surveillance in private areas. Austrian Data Protection Authority, archived from the original on January 28, 2016 ; accessed on June 7, 2017 .