CCTV, widely used in many industries, provides reliable protection and monitoring of a wide variety of production facilities. It is acquired by security agencies to monitor the entrusted facility. Supermarkets, such a system allows you to monitor the actions of customers and employees, to monitor the order in parking lots. There is a small percentage of individuals who purchase CCTV to protect their homes and summer cottages. The scope is diverse and limitless, the main thing is to familiarize yourself with the relevant legislation before purchasing in order to avoid unnecessary problems.
For cultural and entertainment institutions, cameras should be arranged in such a way that the vision of its lenses falls into the field: entrances to auditoriums, ticket offices, sideboards, important objects. In cases with cash registers, camera resolution should be able to make out faces and denominations of banknotes.
Internal cameras are equipped with a video surveillance automation system, with integration into the institution’s security system.
Features of analog CCTV systems
The abbreviation CCTV does not refer to either the class or the type of engineering solution of the equipment.
This means the general name of the video surveillance structure in a limited area.
This concept appeared a long time ago when heavy cameras were used, often black and white, with manual focusing of the lens.
Modern CCTV surveillance cameras are convenient and functional.
The class of engineering solutions has changed, sensitive sensors, servo-driven adjustable optics, and other innovations are used.
Analog cameras are no different in image quality, and in some cases they are superior to their counterparts.
System features include:
- data transmission over inexpensive and anti-interference coaxial cable,
- using a practical combined wire, you can provide cameras with power and receive a data stream,
- analog cameras have the functionality of night shooting, backlight systems,
- when building the system, combined video recorders are used, to which you can simultaneously turn on any type of CCTV cameras and digital devices,
- the range of stable signal transmission is five times higher than the permissible length of a twisted pair line and is 500 meters.
Technologies and protocols that are used when transferring data from analog CCTV cameras - allow you to receive video, audio, transmit servo control signals to change the viewpoint, read the readings of built-in sensors. Today, there are devices on the market that can satisfy any need.
Analog cameras of earlier production had a modest resolution of D1 (704 × 576) or 960H (960 × 576). But with increasing competition, they constantly improved and modernized. To date, analog cameras boast high definition and high resolution HD (1280 × 720), Full HD (1920 × 1080).
In the CCTV system, most often there are analog and digital (IP) cameras. Between themselves, they differ in the external interface and in that the digital camera has an Ethernet network interface. The main advantage of the IP camera in the uninterrupted transmission of video, due to the digital method of signal transmission. The image quality of both types of cameras is the same.
The CCD matrix is such a special chip, which consists of special light-sensitive photodiodes. According to their technical features, CCD-based camcorders are divided into several types.
Modular Camcorders - devices without a housing, with the possibility of mounting in pressure enclosures and hemispheres, are intended for video surveillance inside buildings.
Mini camcorders - placed in special cylindrical or square cases. Also used for video surveillance inside buildings.
Dome Cameras - are installed on the ceiling or a special bracket in the room.
Standard Camcorders - The device assembly for use in various climatic conditions, can be installed indoors and outdoors, but when installed outdoors requires a special lens with heating.
Outdoor camcorders also intended for outdoor use. The requirements for them are anti-vandalism, the ability to work in adverse conditions, dust and moisture resistance ..
Controlled Speed PTZ Camcorders - In addition to the camcorder itself, there are still a zoom and a rotary mechanism in the configuration.
Gyro-stabilized cameras - such cameras are designed for video surveillance on moving objects.
If you make a full review of the standardized range of resolutions of analog cameras - it is worth mentioning the data of obsolete devices.
- D1 format - 740 × 576 pixels.
- 960Н - 960х576.
- HD - 1280 × 720.
- FullHD - 1920 × 1080.
The first size format on the list is for outdated cameras.
Modern devices of the 960H class are quite popular due to their low price.
Their use is limited to internal surveillance systems, where the recognition of small image details is not a key part of the task.
HD format CCTV cameras represent the widest segment of the market, they are distinguished by almost universal application.
And products offering the FullHD video format - provide a clear shot of even moving objects with confidently recognizable small details in the frame.
Image processing devices
Video switcher - such a device sequentially displays the image from all cameras on one monitor.
Quadrator - shows on one monitor data from all cameras at the same time.
Matrix switcher. Allows you to view the image from any camcorder on any monitor. In the CCTV system.
Multiplexer - This is a device for simultaneously viewing images from one or more cameras and further switching to record on media.
In addition to video cameras, we also need lenses.
They are also different: monofocal, varifocal, zoom. Each of them also has its own peculiarity, and is selected individually.
After the video is shot, it needs to be saved somewhere. There are several common drives where your video, audio files can be stored. The drive is one of the most important parts in the CCTV surveillance system.
Depending on the tasks facing the video surveillance system, it is possible to optimally select the characteristics of cameras and reduce overall investment in building an effective structure.
The cameras can be of street performance, with and without water protection, designed to operate in harsh weather conditions. However, basic categorization can be done according to basic technological capabilities.
Video servers and DVRs
These devices are similar in appearance to each other, mainly rack-mountable enclosures, but recorders have software for watching videos. Despite the external similarity, they still differ in structure, although not very much. The function of the DVR is recording, compression, storage, video information from cameras that are connected to it.
It can also give the opportunity to watch video on a connected monitor, if necessary, enlarge, highlight the desired picture, give an alarm, move files to another device. In addition to all these functions, the video server can independently update the software, and first of all it is a kind of video surveillance system controller.
Housing cameras for video surveillance systems - an inexpensive and reliable product. It has several key features.
Firstly, the camera is always aimed at one point. Secondly, no remote focus adjustments are provided.
At the initial connection, the camera position is selected manually, the clarity is rebuilt from the picture on the monitor, and night operation is checked. After that, the housing camera is rigidly fixed and, if necessary, protected by a visor.
This technical solution is one of the most popular. Among the proposals of the retail market, you can choose a CCTV camera of the case type with a viewing angle convenient for solving the task and other characteristics.
Advantages and disadvantages
Key features and benefits:
- Realization of data transmission through the protected coaxial cable.
- You can install cameras that conduct night shooting and have a backlight system.
- Long range stable signal transmission.
- High system reliability, and a wide range of applications.
- The recorded video is well protected.
- The high cost of the system itself and individual components.
- Electronic and technical products require periodic maintenance and replacement of parts in the event of a breakdown.
- A large amount of consumed electricity and Internet traffic, especially when using IP cameras.
The main feature of the dome camera is the shape of the case.
There are two modifications of such devices:
- with fixed focus, the position of the lens inside the dome,
- with servo-driven mechanics, which, by an external control signal, changes the position of the camera unit in two degrees of freedom, adjusts the focal length.
The cameras of the latter type are used when monitoring what is happening over a large area, they can follow moving objects, including automatically, according to the commands of the sensors.
Dome cameras are distinguished by degree of protection. Intended for internal use - have a low strength plastic dome.
Streets are protected from vandals, moisture, the body hemisphere is made of tempered glass, special mechanics of fastening, cable entry are provided.
Most modern analog CCTV cameras on the market use the AHD protocol for data transfer.
However, the potential owner may encounter difficulties in modifying existing video surveillance systems.
This is due to the difference in transmission protocols, which were distributed in separate periods of time for the production of equipment.
Transmission technology developed by Dahua Technologies.
It has several key features:
- the principle of converting the color space into the Lab format is applied, with the separation of the color and brightness component,
- quadratic redundant coding of the signal is used,
- during processing, a software algorithm for error correction and interference compensation was applied.
Cameras operating under this protocol are distinguished by maximum transmission stability, regardless of cable length.
At the same time, the separation of the luminance and color channels made it possible to get rid of crosstalk.
This protocol, despite its effectiveness (allows you to broadcast audio, video, control commands on a single cable), is not widespread.
The reason is the patenting by the author of their development. Third-party CCTV manufacturers were forced to buy a license, therefore, to cheapen their products, they switched to other data exchange protocols as soon as possible.
Hikvision's proprietary protocol. The coding algorithm was not disclosed.
However, the basic principles of sharing information flow are similar to HDCVI solutions. The protocol is also used in a limited device segment.
Last but not least, due to its flaws.
- The coding algorithm does not provide for software error correction.
- With a significant line length, interference can become a problem, especially if the route is a combined cable with power transmission to the camera.
- The basic implementation of the protocol does not provide for the transfer of audio data.
To the credit of the creators, HDTVI is developing, the modern version can broadcast control commands to several subordinate servos, receive feedback signals of reaction, acceptable resistance to interference and interference is achieved. Sound transmission - planned for implementation.
AHD data transfer protocol is considered the most convenient and universal.
Its main difference is a simple conversion, the use of a mixed color space, excessive signal coding.
This allows you to create a device to which any cameras (AHD, IP, analog of older generations) are connected on the basis of a single hardware solution (chipset).
This protocol is an open platform. Its most stable version is used in Nextchip chips, on which many manufacturers build their video surveillance systems.
However, no one bothers to make modifications to the algorithm to obtain special capabilities or improve the functional usefulness of cameras and DVRs.
Hybrid-type DVRs to which external signal sources are connected via the AHD protocol offer:
- easy integration into local computer networks,
- Internet connection
- connection to cloud services for storing video archive.
The speed at which video processing transmitted via the AHD protocol differs allows realizing motion detection at the software level, closed areas in the viewing area, and quickly detecting various camera malfunctions.
Requirements for Used Camcorders
In the process of creating a project of those. tasks for installing cameras, monitors, video recorders or video servers. The norms of GOST R 51558-2008 controlling the functional characteristics of equipment should be taken into account. In cases with video cameras, the following should be taken into account: signal transmission speed, rotary mechanism, motion detection, mechanism that records audio files, if any.
In cases with educational institutions, the requirements of the "Law on Personal Data", as well as special provisions of the law on the protection of the rights of the child, must be taken into account. In particular, they are spelled out in the following documents:
- Constitution of the Russian Federation, Family Code of the Russian Federation,
- The Law on Basic Guarantees of the Rights of the Child in the Russian Federation,
- Federal Law "On Education",
- The law on additional guarantees for the protection of orphans and children without parents,
- Federal Law on Guardianship
On the technical side, for schools where the exam is held, cameras with high-speed compression are needed.
Modern high-quality AHD cameras are considered the future of video surveillance.
They are inexpensive, make it easy to build a system of several types of devices.
CCTV structure can be integrated into computer networks and directly transmit data via the Internet.
And all this - with a huge signal transmission range, low investment in the communication structure and ample opportunity to modify outdated systems.
General recommendations depending on the characteristics of the object of protection
To select a video camera and the formation of technical specifications you need to consider:
- Which section of the protected area needs to be observed. This can be a structure, a control and track strip, a roof or a facade of a building, a corridor, a hall, an office, a warehouse, etc. To observe narrow and long sections (control and track strip, corridor, building facade), a lens with an ARD and a viewing angle of 15 ° to 30 ° will be required. A lens with a manual / fixed aperture will not allow you to get the required depth of field. To observe the vast territory (roof, hall, office, warehouse, etc.), it is necessary to install a lens (it is also possible with a fixed aperture) with a viewing angle from 60 ° to 90 °. At viewing angles of more than 90 °, strong geometric barrel-shaped distortions appear in the image.
- Features of the observation area, such as a large area, limited possibilities for laying telecommunication lines, the complexity of the terrain, the distance from the central observation point, etc.
- At what distance from the monitoring center is it necessary to install a video camera. This determines the video transmission method and the quality of the received image.
- observation of the situation with a minimum length of the "dead" zone,
- general control of the territory,
- providing high quality images day and night,
- detection and / or recognition (recognition of an object falling into the field of view throughout the observation area),
- remote control, etc.
A description of how to solve a particular problem is not provided for in this article. This creative process is best entrusted to professional designers. Now let's talk about how to find them.
General recommendations for choosing an installer for surveillance cameras
It is very important to choose a video camera model that meets most of your requirements inherent in the terms of reference. All the efforts spent on finding the necessary models can be easily reduced to "nil" if the video cameras are to be installed by company employees who have little idea of the professional installation of complex equipment.
There are fewer such companies, but they still exist. They can be easily recognized by a simple criterion. Это время, в течение которого компания занимается монтажом профилированного оборудования. Компания, не стремящаяся к стабильности своего существования на рынке CCTV, не хочет вкладываться в профессиональную подготовку обслуживающего персонала.In such organizations, as a rule, low pay for ordinary performers, a constant staff turnover and, as a result, lack of culture of work performed. This, of course, affects the cost of installation work - it is below market.
In serious companies, this issue is given great attention and the issues of professional installation of equipment are among the priority ones. In addition, the company’s administration does not skimp on the development of professional skills of its employees and seeks to equip them with installation equipment and modern materials necessary for high-quality installation. This can be easily determined by the number of equipped facilities of your chosen organization, the availability of a working draft of the equipped facility, the level of training of installers and the equipment they use when performing work. Such important points need to be clarified in advance, according to reviews from other objects, which should be in excess of the installation organization you need.
That is, a simple conclusion can be made - in order to ensure reliable protection of the facility, it is necessary to choose a company that has no complaints about the timing and quality of installation at commissioned facilities. Any self-respecting company strives to achieve a high professional level of ordinary performers and will not allow untrained people to work. Its competitiveness, success, prosperity and, as a result, our confidence in the future depend on this.
Often, when choosing a potential contractor, we pay attention to the confident behavior of an experienced manager and forget that the operation of the video surveillance system and video recording installed on the site depends on the actual parameters of the equipment and those who install it. Often, the declared characteristics, especially of imported equipment, are not true. In gentle operating conditions, all models work the same and only in difficult real conditions do their features manifest themselves.
2. Install on the street or indoors?
An example of a Falcon eye FE IS720 outdoor video surveillance camera. Price
If you plan to install CCTV cameras outside, then you need to know how to choose a CCTV camera for the street. As a rule, outdoor models are equipped with a special protective case that protects the camera from low temperatures and other adverse environmental influences: rain, sun, etc. The camera body must be airtight, and if possible equipped with a heating system for trouble-free use of the camera in low temperatures. If in your area the thermometer does not fall below zero, then take a look at simpler models.
If you plan to install CCTV cameras in rooms with high humidity, then in this case it is also necessary to use devices enclosed in a moisture-proof housing.
In order to prevent damage to equipment by malefactors, try to install the cameras as high as possible so that it is impossible to get to them without additional equipment - this way you will keep your outdoor CCTV cameras intact and safe in case of attacks on your territory.
For the implementation of indoor video surveillance in the absence of any additional environmental influences, as a rule, ordinary dome cameras without protective housings are used.
3. Viewing angle and focal length
Thus, the smaller the viewing angle of the lens, the more details you can identify if you need to monitor a certain small area, and therefore, the wider the viewing angle (from 90 °), the more space you can cover. So it all depends on the specific tasks.
Line-Pro 560AHD, 2.8-12 mm. Price
It is also possible to purchase a camera whose lens has a certain range of focal lengths - such lenses are collectively called “varifocal”, the approximate range of their focal lengths is 2.8-12 mm. When choosing a camera for video surveillance of this type, you can subsequently manually change the viewing angle depending on your needs. But it is worth noting that this parameter affects the price accordingly - often such devices are much more expensive than cameras whose lens has a constant focal length, but the prices for them, as well as for all CCTV systems, tend to decrease. In the picture, an example of a camera equipped with a varifocal lens - Line-Pro 560AHD with a focal length of the lens 2.8-12 mm. Its price is 4300 rubles, which, you see, is not so expensive.
Criteria Affecting Image Quality
Contrary to popular belief, a large number of megapixels is not a determining factor in good image quality, but is only one of the elements providing it. Of course, there is definitely a difference in picture quality between standard analog and IP, and it is quite significant, but speaking about the modern market and the manufacturers' race for megapixels, before choosing between 2 and 8 megapixels, it’s worthwhile to think carefully, because it’s often good IP camera with a resolution of 2MP for 10 thousand rubles. gives about the same quality as the more expensive one with higher values of this parameter.
Also, the difference between 720p and 1080p is almost not noticeable, despite the twice as many pixels. In addition, with an increase in resolution, parameters such as the sensitivity of the camera matrix and the ability to work in a wide dynamic range (WDR), which also affect the quality of the resulting image, can suffer.
4. Camera sensitivity and lighting conditions
The photosensitivity of the camera plays a big role when conducting round-the-clock video surveillance. The higher its sensitivity, the better the image quality and more shooting options in the twilight and dark.
Now almost all cameras are equipped with IR illumination, which makes it possible to conduct video surveillance even in complete darkness. Also, if necessary, you can equip the camera with an additional infrared spotlight, which vary in range and power of illumination, and viewing angle.
Camera sensitivity means the minimum amount of light (light level) at which the camera can “see” what is happening. The sensitivity of the surveillance camera is usually measured in units of illumination - lux. For example, we give a small table with approximate values of lighting units that are typical for certain places and conditions.
When choosing a camcorder, be sure to look in the specifications for what lighting conditions it is suitable for, and select it for your needs, measuring before that the level of illumination in the place of the intended installation using a light meter. For round-the-clock operation, you will need a camera with a sensitivity of at least 0.01 lux.
In most cases, when installing cameras on the street, the lighting will constantly change throughout the day. In order to get the same picture under such changing conditions (without glare in the bright sun or a dark image in unexpected weather conditions) it is necessary to clarify that the camera has an automatic adjustment of the lens aperture - aperture. By closing or opening the aperture in automatic mode, such cameras maintain the amount of light falling on the matrix within constant limits, which eliminates the appearance of an overexposed or dark image under constantly changing weather conditions and time of day. Therefore, before choosing an outdoor CCTV camera, be sure to check this fact of the presence of automatic iris adjustment.
5. The presence of a wide dynamic range - WDR
WDR action example
Recently, WDR technology has been used much more often. Previously, a wide dynamic range was used only in premium devices, but now, thanks to the appearance of inexpensive sensors with support for this function, it has also begun to be implemented in inexpensive cameras. But do not be deceived if the description of the camera supports this parameter - true WDR is still used only in expensive cameras, in most budget ones - only its semblance, described by the manufacturer in confusing terms, and “wrapped in attractive packaging”.
6. Color or black and white camera?
Updating information!For the most part, today all CCTV cameras are produced in color, with the ability to switch to black and white at night, so the story of the choice between b / w and color of this part of the article has lost its relevance.
When choosing a camera for video surveillance, you need to decide if there is enough monochrome camera in your particular case, or do you still need a color image?
The advantages of black-and-white cameras, in the first place, include their low price compared to color models. Also, monochrome cameras under poor lighting conditions are able to produce a higher quality picture without noise, when the image from a color camera under the same conditions will noticeably "make noise". However, manufacturers took this fact into account, and began to manufacture cameras that shoot in color during the day, and automatically switch to monochrome mode after dark.
The main disadvantage of black-and-white cameras is that they work only in monochrome mode, when like color cameras are capable of transmitting more information about the object of observation, this can be attributed to their main advantage.
The disadvantage of color cameras is their higher price compared to monochrome ones.
7. Day / night mode and a few words about IR illumination
Camera with automatic color / monochrome switching and powerful infrared spotlights Falcon Eye FE-IS 91/100 MLN Patrol. Price
Thus, if you plan to conduct video surveillance both day and night, and want to receive information about all the details of what is happening, including color, choose camera models with day / night modes that automatically turn to monochrome when dark. A necessary item when choosing cameras for night video surveillance is the presence of infrared illumination, which is completely invisible to the human eye, but allows the device to monitor even in complete darkness.
The distance of the IR illumination varies between 5-50 meters, but with the use of powerful IR spotlights can reach large distances. In different cameras, the quality of the backlight may vary. There are cases when the backlight angle does not coincide with the viewing angle of the camera lens, while a bright overexposed spot forms in the center of the frame. In some cameras, the infrared illumination power can be adjusted depending on what is happening in the frame, thereby eliminating excessive illumination of the subject and the appearance of flare in the frame. Therefore, when choosing a camera for round-the-clock surveillance, these features must be taken into account.
Today, in a competitive race, most manufacturers intentionally lower the price of their equipment in order to stimulate demand and weed out competitors. Of course, this is in the hands of the buyer, therefore, when choosing, it’s worth paying attention to this parameter and not looking for a catch at a reduced price - today it’s quite realistic to buy a good camera with a decent resolution and support for modern technologies for a small price.
Among other things, the cameras can be wired and wireless, case-mounted and open-frame, miniature or conventional, rotary, etc., and the selection of a surveillance camera in terms of parameters will depend only on the goals and specific tasks that are planned to be solved using surveillance. Also, do not be lazy, and read reviews about the camera model planned for purchase - this way you will protect yourself from poor-quality goods, or, conversely, affirm your choice in case of positive comments. Good luck in choosing, we hope that this material will be useful to you!