The monitoring system is also calledCCTV monitoring system(English: Closed Circuit Television, abbreviated as CCTV), the typical monitoring system is mainly composed of front-end audioVideo captureEquipment, audio and videotransmission equipment , back-end storage, control, andDisplay deviceThese five major components, of which the back-end equipment can be further divided into the centercontrol equipment And sub control equipment.The front and back end devices have multiple composition modes, and the connection between them (also known astransmission system ）Available throughCoaxial cable、Twisted pair, optical fiber, microwave, wireless, etc.
In the previous introduction, we often mentioned PTZ, but some people have nothing to do with itPerceptual knowledgeActually, there are two PTZalternating current dynamoThe installation platform can move horizontally and vertically.The PTZ we are talking about is different from the PTZ in photographic equipment. Generally speaking, the PTZ in photographic equipment is only onetripod, the orientation can only be adjusted by hand;The pan tilt mentioned by the monitoring system can control its rotation direction at the far end through the control system.There are many types of PTZ: pressUse environmentIt can be divided into indoor type and outdoor type. The main difference is that the outdoor type has good sealing performance, waterproof, dustproof and large load.According to the installation mode, it can be divided into side installation and hoisting, that is, the pan tilt is installed on theceilingIs installed on the wall.According to the shape, it can be divided into ordinary type and spherical type,Ball headThe PTZ is placed in a hemispherical and spherical protective cover. In addition to preventing dust from interfering with the image, it is also concealed, beautiful and fast.The installation environment, installation modeworking voltage , load size, also need to considerPrice performance ratioAnd whether the appearance is beautiful.[1]
If the camera is only fixed to monitor a certain position and does not need to rotate, then onlyCamera bracketYou can meet the requirements.Common camera brackets are simple to install, inexpensive, and of various types.Common supports are short, long, straight and curved, and different models are selected according to different requirements.Main considerations for outdoor supportLoad capacityWhether it meets the requirements is also the installation position, because we found that many outdoor cameras have special installation positions, some of which are installed inTelegraph PoleSome stand onTower craneSome of them are installed on iron frames... Due to various reasons, the existing supports may be difficult to meet the requirements and need to be processed or improved separately, so we won't talk about it here.[1]
The protective cover is also one of the most commonly used equipment in the monitoring system, which is mainly divided into indoor and outdoor.The main difference between indoor protective covers is their size and appearance,surface treatmentWhether it is qualified.Its function is mainly to prevent dust and damage.The sealing performance of outdoor protective cover must be good to ensure that rainwater cannot enter the protective cover to erode the camera.Some outdoor protective covers also haveventilating fan、Heating plateWipers can better protect equipment.When the weather is too hot, the exhaust fan works automatically;The heating plate works automatically when it is too cold;When there is rain on the protective cover glass, the wiper can be started through the control system.Look first when selecting the protective coverOverall structureThe fewer the mounting holes, the better the waterproof. Then check whether the internal lines are easy to connect. Finally, consider the appearance, weight, mounting base, etc.[1]
monitor
The monitor is used to monitor the systemstandard output With the monitor, we can view the images sent from the front end.The monitor is divided into color and black and white, and the size is 9, 10, 12, 14, 15, 17, 21 inches, etc. The commonly used size is 14 inches.The monitor also has resolution, which is the same as the cameraNumber of linesIt indicates that the number of monitor lines is generally required to match the camera in actual use.In addition, some monitors haveAudio input, S-video inputRGBComponent inputIn addition to the audio input monitoring system, most of the other functions are used forimage processingThe work will not be introduced here.[1]
Video amplifier
When the video transmission distance is relatively long, it is better to use a video cable with a larger wire diameter, and it can be added in the lineVideo amplifierenhancesignal intensity To achieve the purpose of long-distance transmission.The video amplifier can enhance the brightnesschromaandSynchronizing signal, but in the lineinterference signalIt will also be amplified. In addition, too many video amplifiers cannot be connected in series in the circuit, otherwise saturation will occur, causingImage distortion。[1]
Video distributor
One video signal corresponds to one monitor or video recorder. If you want to send the image of one camera to multiple managers, you'd better chooseVideo distributor。Because the parallel video signal attenuation is large, it is sent to multipleoutput deviceAfterImpedance mismatchThe image will be seriously distorted and the circuit will be unstable.Video distributor exceptimpedance matching And video gain, which enables video signals to be sent to multiple output devices at the same time without being affected.[1]
Video switcher
multiplevideo signalIf you want to send the video to the same place for monitoring, you can use one monitor for each video, but the monitor occupies a large area and is expensive. If you do not need to monitor all the time, you can use theMonitoring RoomAdd a switcher to set the cameraoutput signalConnected to the input end of the switcher, the output end of the switcher is connected to the monitor. The input end of the switcher is divided into 2, 4, 6, 8, 12, 16 channels, and the output end is divided into single and dual channels. In addition, the audio can be switched synchronously (depending on the model).The switcher has two working modes: manual switching and automatic switching. The manual mode is to turn the switch to whichever way you want;The automatic mode is to make the preset videos switch in a delayed manner in sequence. The switching time can be adjusted by a knob, generally between 1 second and 35 seconds.The switch is cheap (generally only three or five hundred yuan), easy to connect and operate, but only one image in the input can be viewed in a period of time.To view multiple camera images on one monitor at the same time, you need to use imagesSplitter。[1]
Picture splitter
Picture splitterThere are four divisions, nine divisions and sixteen divisions. The images of four, nine and sixteen cameras can be displayed on one monitor at the same time, and can also be sent to a video recorder for recording.Quad segmentation is one of the most commonly used devices, and its performance price ratio is also good. The image quality andContinuityIt can meet most requirements.Nine segment and sixteen segment are expensive, and the resolution and continuity of each image will decline after segmentation, resulting in poor video recording effect.In addition, there are six segment, eight segment and double four segment equipment, but the image ratio, clarity and continuity are not idealUsageSmaller.grossSplitterIn addition to being able toDisplay ImageIn addition, it can also display a single picture, superimpose time and characters, set automatic switching, and connect alarm equipment.[1]
Digital Video Recorder
The most commonly used recording equipment in the monitoring system is the civil video recorder and long delayvideo recorder, because its operation is simple and easy to learn, the videotape is also easy to save and purchase.AndHome video recorderDifferent, the delayed video recorder can work for a long time, recording images for 24 hours (using ordinary VHS video tape) or even hundreds of hours, connecting alarm equipment, automatically starting recording after receiving alarm signal, stacking time and date, preparing automatic video recording program of the video recorder, and selecting recording speed,When the video tape ends, it will automatically stop or rewind... Although the delay video recorder has outstanding performance, it is expensive, and the current resolution is not very high. When the delay video is recorded, part of the image will also be lost, and the playback image will jump one by one.[1]
Monitoring management platform
It combines modern soundVideo compression technology、Network communication technologyComputer control technology and streaming media transmission technology adopt modular software design concept to realize the needs of different customers in the form of component modules;Centralized management andnetwork transmissionAs the core, it completes the whole process of information collection, transmission, control, management and storage, and can be built in various private networks/LAN/MAN/WANIn addition, Hypervision Technology cooperates with mainstream hardware manufacturers in the market and is compatible with a variety of brand hardware products.It really realizes monitoring networking and centralized management,Authorized userIt can monitor the site on any computer of the networkReal time monitoring, providing a powerful and flexible networkCentralized monitoringComprehensive solutions.[1]
disk array
In large monitoring systems, due to the large number of monitoring videos and large storagedisk array 。The disk array is composed of many inexpensive disks, which are combined into a disk group with huge capacity. The addition effect produced by the data provided by individual disks is used to improve the entire diskSystem Effectiveness 。Using this technology, the data is cut into many sections and stored on each hard disk.
The disk array can also use the concept of Parity Check tohard disk failureThe data can still be read whenData reconstructionAfter calculation, the data is re placed into the new hard disk.[1]
Color camera: High definition and color form sharp image contrast;
Hemisphere black and white/color camera: economical and convenient, with its own lens, mounting bracket, andEnvironmental atmosphereCoordination and coherence;
Lens: adjust the shooting range to obtain a suitable image by changing the lens. The lens can cooperate with a series of cameras.Divided into: fixed focus lens andZoom lens。Fixed focus lensWide angle, standard andlong-focusDistance type, also suitable for use in places with constant lighting conditionsmanual iris Lens or more suitable for use in places with frequent changes in lightingAuto iris lens ；The adjustment of zoom lens can meet the requirements offieldrequirement.
infrared lightProjector: provide the lighting required for the camera to work at night.
video cameraprotection coverAnd support: effectively prevent man-made damage to the camera, play a waterproof, dust-proof, fixed role.Omni directional PTZ: It can rotate up, down, left and right to realize omnidirectional monitoring.
Pan tilt lens controller: remote control the pan tilt in all directionsCamera lensFocus and aperture adjustment.
Monitor head: It can monitor the scene sound with high sensitivity while monitoring the scene image.
monitor: Display the image picked up by the camera with high quality.There are many sizes of black and whiteColor monitorFor selection.[1]
Introduction to terminal monitoring equipment
Sequential videoaudio switcher : The camera images from 2 to 12 channels and the correspondingsound signalSwitch in sequence. The sequence switching image signals are automatically displayed in sequence on the monitor, and the switching time can be adjusted.You can also manually switch the selection orbypassIsolate a designated cameraimage display。
videoimage processor : Multiple images can be split and displayed on one monitor screen at the same time by using a video image processor, or one image can be selected from multiple imagesFull screen display。With alarmInput interfaceIn case of alarm, it will automatically switch to display the full screen image of the corresponding camera.More advanced processor with video playback control function.
majorvideo recorder: Use a box for ordinary household useVideo tapeIt can easily record all camera images and audio signals of the system for 24 hours or even 168 hours to 960 hours, and the management is simple and convenient;When the video is replayed, it can display more thanPicture segmentationThe image can be manually switched to display the full screen image of a certain camera;Abnormal image confirmation can be performed in high-speed playback;Received from sensorAlarm signal, YesAuto startVideo recorder or switch to real-time video recording state;The monitor displays the operating program and function menu.[1]
Monitoring does not simply meanCCTV monitoring systemHowever, in the traditional sense, the monitoring system consists of front-end cameras (including:Dome Camera、infrared camera, all-in-one machine, etc.) plus mid end equipment（Optical transceiver、Network video serverEtc.) plus back-end device host（Digital Video Recorder, matrix, etc.) (a monitoring management platform of the third generation monitoring system can replace traditional equipment).[1]
System comparison
Announce
edit
1. Traditional analog monitoring system
The traditional analog monitoring mode was most popular when the road monitoring application was just introduced in large and medium-sized cities in China, but it has been declining in recent years. Its main defects are as follows:
Since the distance between the road monitoring points and the monitoring center is usually several kilometers or even dozens of kilometerstransmission distance It is obviously impossible to reach a video cable only about 300 meters long. The conventional solution is to lay optical cables between the monitoring point and the monitoring center as transmission channels, and connect optical terminals at both ends of the optical cables as video/optical signal conversion equipment.However, this solution is too expensive, and the cost of optical cable laying alone accounts for the entire monitoring systemTotal investment cost80% or more;
The system structure is complex, and the monitoring center has a variety of equipment, which is cumbersome to operate;
The system is composed ofvideo camera, MonitoringTV wall, video recorder, control matrixPicture splitter, decoder and other auxiliary equipment, taking coaxial cable as imageTransmission medium, withShielded twisted pairIn order to control the signal transmission medium, there are many equipment with complex structure and poor scalability, and most of the equipment is special equipment, so the operator must be trained to have the correspondingOperational capability。
2. The second generation quasi digital video monitoring system with hard disk recorder as the core
Compared with the traditional analog monitoring modeDigital hard disk video recorderThe quasi digital video monitoring system of.In the application of road monitoring, the digital hard disk recorder is placed at the front end of the road monitoring and connected to the camera. It can perform analog/digital conversion and compression on the video source signal and then record it on the local hard disk. It can be uploaded to themonitoring center It breaks away from the limitation that traditional analog monitoring must lay optical cables, and greatly simplifies the system structure.However, due to its ownTechnical architectureThe digital hard disk video recorder has always been unable to solve the problem that the image transmission delay in network-based remote centralized monitoring applications is too long, and multi-channel simultaneous monitoring cannot be realizedIntegrationPoor etc.
The third generation full digital remote videoCentralized monitoringThe system is based on the network, with digital video processing technology as the core, and comprehensive utilizationPhotoelectric sensorDigital image processingEmbedded computer system、Data transmission network、Auto-ControlA new digital monitoring mode based on artificial intelligence and other technologies. It not only has the computer fast processing capability of the second generation quasi digital video monitoring modeDigital informationAnti interference capability, convenientQuick queryRecording, videoClear imageAnd displaying multiple images on a single computer, and relying on the networkbroadband network Through the IP network, the monitoring center and the monitoring targets anywhere that can be reached by the network are combined into a system, which truly meets the remote, real-time and centralized requirements of the video monitoring system. Its coreTechnical productsIt is the network video server.
4. The third generation full digital remote video centralized monitoring system with the monitoring center management platform as the core
The overall architecture of the video monitoring system is based on the construction of the video monitoring system, which is mainly divided into front-end TV monitoring systemprivate network Transmission system, command and monitoring system, control and management platformstorage system The monitoring center management platform is the management core.[1]
along withsafety consciousnessWith the enhancement of, the video surveillance system has gradually entered our ordinary people's homes.videoMonitoring schemeIt is also emerging in endlessly, so what principles should be followed in the installation of monitoring system?When installing the monitoring system, the following eight monitoring installation principles should be considered first:
1、Real time: It is particularly important to monitor the real-time performance of the system.It is precisely because of the real-time nature of the monitoring system that the monitoring system is so necessary.
3、Scalability: The monitoring system equipment adopts a modular structure, and the system canMonitoring objectWhen the,, or monitoring requirements change, it is convenient and flexible to expand on hardware and software, that is, there is no need to change the network structure and main software and hardware equipment.
4、Openness: The monitoring system follows the principle of openness, and the system providesinternational standardSoftware, hardware, communications, networks, operating systems, andDatabase management systemAnd other aspects of the interface and tools, so that the system has good flexibilitycompatibility, scalability andPortability。The whole network is aopen system, can be compatible with the products of multiple monitoring manufacturers, and can supportSecondary development。
5. Standardization: the equipment and technology adopted by the monitoring system comply with international general standards.This can give you a reassuring guarantee.
6. Flexibility: the monitoring system networking mode is flexible,system functionFlexible configuration, making full use of existing video surveillanceSubsystemnetwork resource。The system integrates other subsystems into it, which can meet the business requirements of different monitoring units. The software has comprehensive functions and is easy to configure.
7、progressiveness: The monitoring system is as advanced as possible on the premise of satisfying reliability and practicability.The whole system will remain advanced within ten years after completion, and the equipment and technology used in the system can adapt to future development and be easily upgraded.It will become an advanced, adaptable, reliableConfidentialityGood, simple network expansion, strong connection data processing ability, and simple system operationSecurity system。
8. Practicality: the video monitoring system has the ability and level to complete the functions required in the project.The system meets the requirements of relevant domestic and foreign specifications actually required by the project, and is easy to realize and operate.From the user's point of view, make full use of existing resources, try to reduce the system cost, so that the system has a highPrice performance ratio。[1]
The first generation of video surveillance: traditional analog closed circuit video surveillance system (CCTV): relying on cameras, cables, video recorders, monitors, etcspecial equipment。For example, the camera outputs through a dedicated coaxial cablevideo signal。Cable connection to dedicated analogVideo equipment, such asVideo picture splitter, matrixkvm , cassette recorder（VCR）And video monitor, etc.Analog CCTV has many limitations: limitedMonitoring capabilityIt only supports local monitoring and is subject toAnalog videoCable transmission length and cable amplifier limits.Scalability limited systems are usually subject to videoPicture splitter, matrix and switcher input capacity limits.The video load user must take out or replace the new video tape from the video recorder for storage, and the video tape is easy to be lost, stolen or accidentallyErase。Low quality video recording is the main limiting factor.The video quality decreases as the number of copies increases.
The second generation of video monitoring: the current "analog digital" monitoring system (DVR): the "analog digital" monitoring system is based onDigital hard disk video recorderDVR is the core semi analog semi digital scheme. Coaxial cable is still used to output video signals from camera to DVR. DVR supports both video recording and playback, and can support limitedIP networkDue to the diversity of DVR products and the lack of standards, this generation of system is a non-standard closed system, and DVR system still has many limitations:
The "analog digital" scheme of complex cabling still requires a separate video cable to be installed on each camera, resulting in complex cabling.The typical limitation of limited scalability DVR is that it can only expand 16 cameras at a time.
Limited manageability still requires external servers and management software to control multiple DVRs or monitoring points.
LimitedRemote monitoring/control abilityStill can't choose from anyClientAccess any camera.You can only access the camera indirectly through DVR.Disk failure risk vsRAIDCompared with tape, the "analog digital" scheme has no protection and is easy to lose.
Third generation video surveillance: full IP in the futureVideo monitoring system(IPVS): fullIP video monitoringThe system is significantly different from the previous two schemes.The advantage of this system is that the camera has a built-in Web server and providesEthernetPort.These cameras generateJPEGorMPEG4data file, which can be accessed, monitored, recorded and printed by any authorized client from any location in the network, instead of generating continuousAnalog video signalFormal images.
The third generation video monitoring system is based on the networkdigital video Compression, transmission, storage and playback ofimage analysisTo feature, and withalarm system 、Access control systemThe perfect integration into one use platform triggered a video surveillance industrytechnological revolution, quickly attracted the attention of the security industry and users.Compared with the first generation traditional closed circuit television monitoring system (CCTV) and the second generation semi digital monitoring system (DVR), the third generation monitoring system is based onTCP/IP network protocol, appeared in the concept of distribution, and expanded the monitoring mode into a decentralized and centralized complementary,InfinityThe scope of monitoring has been expanded.In terms of hardware equipment, the third generation system uses more advanced D/AA/DConversion equipmentVideo server, or built-in processorweb cameraholdimage processing(Acquisition, compressionprotocol conversion , transmission) is set at the monitoring point, and the ubiquitous Internet and LAN are used to achieve plug and play in the full range of networks, realizingImage acquisitionThe whole process of digitalization of transmission, video recording and final output is also more determined by the system, so it is a truly all supervision instituteNetwork monitoring system。In particular, the effect that the site environment is bad or not convenient for direct penetration into the site.It can perfectly solve the demand for cross regional monitoring. In practical application, the security system often needs to be expanded in scale due to the increased demand for use. The consideration of pre planning and expected capacity is directly related to the future expansion cost.In general, each component of a system may become an indeterminate number of future expansion costs. The more components, the greater the uncertainty, the more difficult the cost is to control.So, insystem capacity Under sufficient premise, the cost of each new surveillance point cannot be expected by the traditional CCTV system, but the third generation is all digitalMonitoring systemCan be expected and mastered.
Digitization is the future trend.Browser has become the most accepted front-end application tool in the entire software industry, and the most convenient and popular front-end in Internet and Intranet environmentsapplication programnamelyBrowser, over the InternetWANAccess is even more so, in order to make aEnterprise resourcesCan be shared from afar,application systemThe Browser interface should be supported.
Cabling itself is a huge hardware project, and the cost of management and expansion is increasing day by day.With informationEngineering technologyThe traditional application system is nowAll haveIt can be digitized and then implemented on this architecture.Therefore, when evaluating the introduction of a new system, whether the existing IT architecture can be used to save huge cabling costs has become an important consideration.
To sum up, a completesystem designImportant factors to be considered include the compatibility, integrationInclusion。[2]
detailed description
Announce
edit
typicalClosed circuit monitoring systemIt is mainly composed of four parts: camera part, transmission part, control and recording part and display part.
Camera part
Huasaiao monitoring system
The camera part is the front part of the TV monitoring system and the "eye" of the whole system.When the monitored area is large, install the cameraZoom lensTo make the distance that the camera can observe farther and clearer;The camera can also be installed onElectric pan tiltThe PTZ can drive the camera to rotate horizontally and vertically, so that the camera can cover a larger angle.In some cases, especially in outdoor applications, special protective covers should be installed for cameras and lenses, even for PTZ, in order to prevent dust, rain, high and low temperatures, corrosion, etcProtective measures。[2]
Transmission part
The transmission part is the image of the systemSignal path。Generally speaking, the transmission part refers only to the transmitted image and sound signals.At the same time, due to the need forcontrol centeradoptConsoleControl the camera, lens, pan tilt, etc., so the transmission system also includescontrol signalTransmission of.
The control and recording part is responsible for the control of the camera and its auxiliary parts (such as lens, pan tilt), and the recording of image and sound signals.Digital Video RecorderOftechnological development It is more perfect. It can not only record images and sounds, but also include functions such as picture segmentation and switching, pan tilt and lens control, basically replacing the previously used pictureskvm 、Picture splitter, PTZ controller, lens controller and other products.If the customer requests to be able toFastball）For very convenient control, a control keyboard can be added.[2]
Display section
Base station anti-theft alarm monitoring system
The display part is generally composed of several or more monitors. LCD, plasma, DLP large screen and other technologies are gradually replacing the traditionalCRT Monitor。When the number of cameras is not very large and the requirements are not very high, the monitor is usually directly connected to theDigital Video RecorderJust go up.If there are many cameras and multiple monitors are required to switch and display the images in a complex way, a "matrix" must be equipped to achieve this.
Special monitors are expensive. In order to save money, ordinary televisions can also be used instead. However, televisions are not suitable to be turned on 24 hours a dayfailure rateIt will be very high and cause fire.
The monitoring system follows the computer'sDevelopment levelHas been improved byAnalog systemTransform to digital system, the digital system is more complete in function than the analog system, and the operation is extremely intelligent and centralized.Applicable places of monitoring system include:
Government agencies, power telecommunications, prisons, military, banks, vaults, supermarkets, shopping malls, hotels, residential areas, schools, office buildingsRoad monitoringEtc.[2]
Type classification
Announce
edit
Low cost
In this system, the sub control keyboard SP8050 is used to replace the PTZ lens controller, so that the connection line of the system is relatively simple.SP8050 can also be controlled remotelykvm (SP2000 series) andPicture splitter。The switcher also has an alarm function. When there is an alarm, it can automatically switch out the alarm field camera and record.In terms of cost, it is lower than the system using system host/matrix switcher.
Small model
What size of system is requiredSystem hostThere are no strict restrictions.Generally speaking, when the number of omni-directional cameras in the monitoring system reaches more than 3 to 4, small system hosts can be considered.Although multiple sets are usedOne wayThe controller or a multi-channel (such as 4-way or 6-way) controller can also control the omnidirectional camera, but this requires a large number of control cables (at least one 10 core cable for each circuit), and the cable length will be too long (caused by the resistance of long wiresVoltage dropIt may cause the pan tilt and electric lens to move slowly or even not), and the whole system will also appear messy.
Generally speaking, the use of the system host will increase the cost of the entire monitoring system, because the cost of the system host is higher than that of ordinarykvm High, and the supporting front enddecoderIts price is also higher than that of ordinary single channel controller.However, considering the wiring, the decoder and the system host are connected by bus, so there are not many cables in the system (only one two cores are neededCommunication cables）。In addition, most integrated system hosts have alarm detector interfaces, which can easilyAnti theft alarm systemIt is integrated with the TV monitoring system.When there is a detector alarm, the host can also automatically switch the main monitor screen to the screen taken by the scene camera where the alarm occurs.Figure 1-5 shows the structure of a small TV monitoring system using a system host.[2]
Closed circuit monitoring
CCTV monitoring system: YesSecurity technology preventionAn important part of the system, it is an advanced comprehensive system with strong defense capabilityRemote control cameraIts auxiliary equipment (lens, PTZ, etc.) can directly watch all the conditions of the monitored place, so that the conditions of the monitored place can be seen at a glance.At the same time, the TV monitoring system can also be used to prevent theft
The alarm system and other security technology prevention systems are jointly operated, which makes its prevention ability more powerful.
Components: CCTV monitoring system is mainly analog TV monitoring system, which is called CCTV for short in English.General monitoring system mainly consists ofFront end equipment、transmission equipment Back end controlDisplay deviceThese three parts are composed.The front-end equipment includes power supply equipment and imaging equipment;Transmission equipment is divided intoCoaxial cable、Twisted pairAnd optical fiber;The back-end equipment includes video distribution equipmentstorage device, display equipment and operating equipment.[2]
Monitoring type
The TV monitoring system also often needs to monitor the on-site voice (for example, the bank teller system monitoring system)System structureSeen from the above, the whole TV monitoring system consists of two parts: image and sound.Due to the increase of sound signal acquisition and transmission, in a sense, the scale of the system is twice as large as that of a pure fixed-point image monitoring systemTransmission processThe synchronization of image and sound signal shall also be ensured.
For simple one-to-one structure (camera - video recorder - monitor), just add monitor head and audioTransmission line, you can viewsound signalDisplay, monitor and record together.For the switching monitoring system, it is necessary to configure video and audio synchronizationkvm It can switch from multiple input video and audio signals and output the selected video and corresponding audio signals.System composition and functions of each part.[2]
The monitoring system mainly consists of the following parts:
Video captureThe system is mainly composed ofObservation pointIt is composed of video cameras and mainly completes video imagessignal acquisition 。By existing 58 high-performance colorDigital video cameraform.It mainly implementsAcquisition pointVideo capture for.Among them, 20 cameras are equipped with pan tilt devices, which can mainly monitor a wider area.Pan tilt lens control system:
The PTZ lens control system is mainly composed of PTZ and controller.Used to completemonitoring center Remote control cameraThe change of the observation position and the zoom in and zoom out of the observation point image.Signal transmission system:
In this system, the signal transmission system mainly includes power signal transmission, video signal transmission andcontrol signalOfTransmission lineIt consists of three parts.Video processing system:
The video processing system mainly completes the digital processing of video signals, the display of image signals, the storage of image signals, and theRemote transmission。In this system, 4 sets of 16 channel hard disk video recording and remote transmission systems are used to realize the display, video recording, playback and remote browsing of all acquisition points.System function description:
1. Adopt the most advanced digital compression technology（MPEG-4）Display, storage, playback and remote transmission of images through computer processing
2. Each channel of display, storage and playback can reach 6.25 frames/second
3、Display resolutionUp to 768 * 576, storage and playback resolution up to 384 * 288
4. The observation of each observation point can beHard disk storage。
7. SystemIntegrationHigh can realize all operations on the computer
8. All adopt WINDOWS interface, easy and flexible operation
9. Available throughPSTN、ISDN、LANWAN enables remote image browsing.
Comprehensive monitoring type
The omni-directional monitoring system integrates the aboveFixed point monitoring systemThe fixed focus lens in is replaced byElectric zoomLens, and add omnidirectional pan tilt that can move up, down, left and right (there are two motors inside the pan tilt), so that the camera at each monitoring point can scan up, down, left and right, and the focal length of the equipped lens can also change within a certain range (the monitoring scene can be extended or advanced).Obviously, the motion of the PTZ and the electric lens needs to be controlled by the controller or the decoder coordinated with the system host.
Compared with the simplest fixed-point monitoring system, the simplest omnidirectional monitoring system adds an omnidirectional pan tilt and an electric zoom lens at the front end, and adds a controller in the control room, such as SP3801. In addition, an additional multi-core (10 core or 12 core) is required from the front end to the control roomControl cable。Taking the monitoring system of a small garment factory as an example, two omnidirectional cameras were installed in its garment workshop, and an ordinary TV set and a TV set were configured in the factory director's officekvm And two controllers. When the factory director needs to know about the situation of the workshop, he just needs to select the image of a camera through the switcher andOperation controllerIt enables the camera to scan the whole monitoring site, and it can also conduct fixed-point monitoring on a certain part.
In practical applications, it is not necessary to configure every monitoring point in an all-round way. Generally, only a few special monitoring points in the whole monitoring system are equipped with all-round equipment.For example, in the previous oneGuesthouseIn the fixed-point monitoring system of, we can also consider changing the fixed-point camera monitoring the parking lot situation to an omnidirectional camera (replacing the electric zoom lens and adding the omnidirectional pan tilt), and then adding a controller in the control room, so that we can expand the monitoring range of the parking lot, which can not only scan the entire parking lot, but also monitor a certain part.Especially when moving in the camera, you can see the license plate number clearly.[2]
Fixed point type
The simplestFixed point monitoring systemIt is to set a fixed point camera (the camera is equipped with a fixed focus lens) at the monitoring site, and transmit the video signal to the monitor in the monitoring room through the coaxial cable.For example, a camera is placed at the gate of a small factory, and the video signal is transmitted to the monitor (or TV set) in the factory office through the coaxial cable, so that the management personnel can see who is late for work or leaves early, and whether he or she has carried the goods in the factory when leaving the factory.If another VCR is configured, the monitored images can also be recorded for future retrieval and verification.
This simple fixed-point monitoring system is suitable for many applications.When the number of cameras is large, multiple channels can be usedkvm 、Picture splitterOr the system host.Taking the headquarters of a famous foreign enterprise as an example, the headquarters has lost high-end products for many timesNotebook computerLater, fixed point cameras were installed at all 12 exits of each floor, and 3 cameras were equippedFour picture splitterAnd 24-hour real-time video recorder, which effectively put an end to the above theft phenomenon.
A guest house also adopts this simple fixed-point monitoring system.This is to install a fixed point at both ends of the guest room passageway on the first to sixth floorsBlack and white camera, plus 16 cameras at 4 monitoring points, such as the gate, lobby, back door and parking lot, and one more camera16 Picture splitterOne set 29 inchesLarge screen color TVAnd a 24-hour video recorder constitute a complete monitoring system.
When the number of monitored points increases, the scale of the system will become larger, but if there is no other additional equipment and requirements, this kind of monitoring system can still be classified as a simple fixed-point system. Take the closed-circuit television monitoring system of a supermarket as an exampleBusiness areaIt is large (the upper and lower floors are about 16000 m2 in total), and there are many shelves. A total of 48 fixed-point black and white cameras are installed.The signals of these 48 cameras are divided into three groups and received the corresponding16 Picture splitter17 inch black and white monitor and 24 hour video recorder (additionalAnti theft alarm systemandPublic broadcasting/Background music system, omitted here).[2]
Installation steps
Announce
edit
Installation inspection
one
Power on the cameras one by one for detection and rough adjustment, and install the cameras after they are in normal working condition;
two
Check the horizontal and vertical rotation angles of the PTZ, and determine the starting point direction of PTZ rotation according to the design requirements;
three
Check the tightness of the camera in the protective sleeve;
four
Check the installation dimensions of camera base and bracket or PTZ.
five
In the process of moving and erecting the camera, the lens cover shall not be opened.
six
The camera device shall be installed firmly.
seven
The cable led out from the camera should have a margin of 1m, which should not affect the rotation of the camera.The cable and power line of the camera shall be fixed, and the plug shall not be used to bear the dead weight of the cable.
eight
First, the camera shall be preliminarily installed. After power on for trial inspection and fine adjustment, various functions shall be checked, and the coverage and image quality of the monitoring area shall be observed. The camera can be fixed only after it meets the requirements.[2]
Line laying
Cable laying shall meet the following requirements:
one
The bending radius of the cable shall be greater than 15 times of the cable diameter;
two
The power line should be laid separately from the signal line and control line;
three
The connection of cables should be avoided when selecting cables;
four
When connecting cables, special connectors shall be used.
five
Pipe and cable laying shall meet the following requirements:
six
Grease or talcum powder should be applied when laying cables;
seven
The lead sheet shall be padded between the nozzle and the cable, and the lead sheet shall be wrapped on the nozzle;
eight
The cable entering the pipe hole shall be kept straight, and damp proof, anti-corrosion, rat proof and other treatment measures shall be taken.[2]
Central equipment
one
The hard disk video recorder shall be placed stably and neatly, avoiding direct sunlight.
two
The display shall be installed so that the screen is not directly exposed to external light. When there is unavoidable light, a light shield shall be added to cover it.
three
The external adjustable part of the display shall be exposed in a position convenient for operation and can be provided with a protective cover.[2]
system detection
Test content:
systemFunction test: Pan tilt rotation, adjustment of lens and aperture, focusing and magnification, image switching, detection of protective cover function;
Image quality inspection: inspect the image clarity and anti-interference ability under the standard illuminance of the camera;
Overall function detection of the system: the function detection shall include the monitoring range of the video security monitoring system, the access rate and integrity rate of on-site equipment;
Switching, control, programming, patrol, recording and other functions of hard disk video host;For the digital video recording monitoring system, the host crash recording, image display and recording speedimage quality, control function of front-end equipment andcommunication interfaceFunctions, remote networking functions, etc;
In addition to detecting the recording speed, the digital hard disk video monitoring system should also detect the retrieval, playback and other functions of records;Image recording of video security monitoring systemSave timeManagement requirements shall be met.The qualification rate of camera spot check shall be 100%;
All functions of the system are tested. If the function meets the design requirements, it is qualified. If the qualification rate is 100%, it is qualified.[2]
Options
Announce
edit
Installation and material selection
1、power cord: "Flame retardant" cables shall be selected, with strong skin. On the premise of cost saving, thicker cables shall be used as far as possible to reduce the attenuation of power supply.
2. Video cable: SYV75-3 cable can transmit within 300 meters, 75-5 cable can transmit within 500 meters, and 75-7 cable can transmit 800 meters;If the distance exceeds 500 meters, "optical cable" should be considered.In addition, pay attention to the quality of "coaxial cable".
3、Control line: "Shielded" 2 * 1.0 cable is generally used,RVVP2*1.0。
4、Conduit: General“PVC tube”That's right. For projects that need to be "buried and explosion-proof", "galvanized" steel pipes should be selected.[2]
equipment installation
1. Console and cabinet: the installation shall be stable and firm, and the height shall be appropriate for easy operation and maintenance.The distance from the back and side of the cabinet rack to the wall is convenient for maintenance.
2. Control and display equipment: the installation shall be easy to operate and reliable, the monitor shall be free from "external light", and the equipment shall be provided with "ventilation and heat dissipation" measures.
3. Set trunking holes: all cables in the cabinet, according to the location,Equipment cableThe slot and inlet hole shall be bound neatly, numbered and marked.
4. Equipment heat dissipation and ventilation:control equipment The working environment should be clean in the air-conditioned room. The space to be reserved in the equipment room can be equipped with fans for ventilation.
5. DetectionVoltage to ground: In the monitoring room, the live wire, neutral wire and ground wire of the power supply are connected according to the specifications.Detect the ground voltage of each equipment's "shell" and "video cable". The higher the voltage, the more likely to cause damage to the "camera". Avoid "hot plugging" video cable.[2]
Installation method
1. Monitoring installation height: the installation height of indoor cameras should be 2.5~5m, and that of outdoor cameras should be 3.5~10m;The elevator is installed on its top.
5. Infrared Note:Infrared lampAvoid direct light source and "all black objects, open places, water", etc. It is easy to absorb infrared light, which greatly weakens the infrared effect.
6. Installation of PTZ: it shall be firm and free from shaking during rotation. Check whether the "rotation range of PTZ" is normal. The decoder shall be installed near the PTZ.[2]
Perform normal operation on the monitoring systemEquipment maintenanceThe required basic maintenance conditions are "four complete", that is, complete spare parts, complete accessories, complete tools and complete instruments.In general, the maintenance of each system must establish correspondingSpare parts warehouseIt mainly stores some important equipment that is not easy to repair immediately after damage, such as cameras, lenses, monitors, etc.Once these devices fail, the system may not operate normally and must be replaced in time. Therefore, a certain number of spare parts must be availableInventoryIt must be updated continuously according to whether the equipment can be repaired and the characteristics of the equipment's operation cycle.
Spare parts are mainly the additional configuration of various discrete components and modules in the equipment, which can be prepared more for equipment maintenance.Commonly used accessories mainly include various types required by the circuitIntegrated circuit chipAnd various circuit discrete components.Other large equipment must be equipped with certainfunctional module In case of emergency.In this way, after maintenance, good benefits can be generated with small investment, and a large amount of funds for updating equipment can be saved.
2. Some precautions in equipment maintenance:Maintenance processSome situations should be prevented to make the equipment operate normally as far as possible, mainly including moisture-proof, dust-proof, anti-corrosion, lightning protection and interference prevention.
Damp proof, dustproof and anti-corrosion
For various acquisition equipment of the monitoring system, since the equipment is directly placed in a dusty environment, which will have a direct impact on the operation of the equipment, it is necessary to focus on the maintenance of moisture, dust and corrosion prevention.If the camera is hung at the end of the shed for a long time, the protective cover andDustproof glassIt will soon be covered with a mixture of dust, carbon ash, etc., which is dirty, black and corrosive, seriously affecting the viewing effect, and also causing damage to the equipment. Therefore, it is necessary to do a good job in dust prevention and anti-corrosion maintenance of the camera.In some places with heavy moisture, the installation position and equipment protection must be adjusted during maintenance to improve the moisture-proof ability of the equipment itself. At the same time, dehumidification measures should be taken frequently in high humidity areas to solve the moisture-proof problem.
Lightning protection and interference prevention
Once engaged inElectromechanical systemAs everyone knows, it is common for equipment to be struck by lightning in thunderstorm weatherMonitoring equipmentNormal operation causes great potential safety hazards. Therefore, the monitoring equipment must pay great attention to lightning protection during maintenance.Lightning protection measures are mainly to do a good job of lightning protection grounding grid for equipment grounding, and to do a good job of independent grounding resistance less than 1 Ω according to the equipotential body schemeGrounding grid, eliminateWeak current systemOfLightning protection groundingThe practice of mixing with power lightning protection grounding grid to prevent power grounding gridClutterInterference to equipment.Anti interference is mainly to adhere to the principle of separating strong and weak electricity when wiring, separate power cables from communication cables and video cables, and strictly follow the wiring specifications of communication and power industries.For cameras installed outdoors, the camera must be insulated from the pole, and the camera must be insulated from the protective cover.
Closed circuit television monitoring system: ensure front-end equipmentSystem controlFunction, monitoring system function, display function, record playback functionAlarm linkageThe function and image review function work normally to ensure thatVideo security monitoring systemThe reserved interface works normally to ensure the systemTime scaleAnd Beijingstandard time The error shall not exceed 60 seconds.The equipment for CCTV monitoring system maintenance mainly includes: camera, PTZ, monitor, video matrix,Digital Video RecorderMaintenance of all equipment of existing projects of CCTV monitoring system, such as decoder, system line, etc.
Infrared alarm system: ensure infrared alarm function, damage prevention and fault alarm function, recording and display function, alarmresponse timeAlarm recheck function works normally to ensure alarmSound levelMeet the requirements to ensure that the reserved interface of the alarm system is normal.Infrared alarmsystem maintenanceIt mainly includes:Infrared radiation detector、Alarm hostLine maintenance.
Security comprehensiveinformation management: Ensure that the supporting linkage between each subsystem and system works normally, the protection is firm, and the working environment is clean.ensureLeakage protectionFunctionUPSThe backup power supply function, lightning protection and grounding function work normally to ensure that the transmission function works normally.Security comprehensive information management and maintenance content: monitoring hostDigital Video RecorderMaintenance of monitoring system platform and video data.[2]
Current situation of urban video monitoring system
Announce
edit
along withPing'an City、smart cityThe increasing demand for security in construction and other industries has multiplied the number of urban video monitoring system equipment.These soaring demands and cumulativeSecurity equipment, providing new opportunities and challenges for security operation and maintenance services.The scale of the video monitoring system is constantly expanding, with tens of thousands of monitoring points, and the workload of system equipment maintenance and repair management is greatly increased,AloneThe manual patrol inspection can no longer meet the business needs.manyBusiness environmentAll monitoring videos, network resources, storage and application systems must be available 24 hours a day, and video monitoring andIntelligent analysisThe utility of.
The country is also driving video surveillance from top to bottomSystem applicationStandardization and specialization.In 2015, the Ministry of Public Security, the National Development and Reform Commission, the Central Comprehensive Administration Office and other nine ministries and commissions jointly issued thePublic safetySome Opinions on the Construction of Video Surveillance Network Application Work.The Opinions put forward the goal of "universal coverage, network sharing, full time availability, and full process control" of public security video surveillance construction networking application by 2020, requiring key pointsPublic areaVideo monitoring in key industriesCoverage100%, install videos in key public security areasSurveillance cameraThe serviceability rate reached 98%, and the serviceability rate of video surveillance cameras installed in key industries and fields involving public areas reached 95%.[3]
