Security surveillance video technology knowledge
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May 25 21:07:28, 2023
There are more and more employees monitoring the security industry. For newcomers who have just joined the industry, they may start with the installation of the most basic equipment and gradually gain experience in practice before they can become project managers for independent projects. So what should you pay attention to during the installation of the surveillance camera?
1, location needs
For surveillance cameras, the location is directly related to the imaging effect of the device. Therefore, many users regard the monitoring effect as the primary reference for monitoring the installation position of the camera.
However, they ignore the very important point: surveillance cameras are not omnipotent. In terms of installation location, it also has its own requirements. First, in the installation position, in order to enable the camera to avoid interference from the surrounding environment, realize a Better photo and survival effects. When installing in an indoor environment, we must ensure that the height of the equipment is not less than 2.5 meters, and in the outdoor environment, we should also place the monitoring equipment at a height of 3.5 meters or more from the ground. Otherwise, whether it is from the camera self-protection or equipment monitoring, there will be many negative effects. Only after considering these most basic issues, the angle is the factor we need to consider.
2, installation angle
Commonly used cameras are mainly divided into two types: gun type and hemisphere type. Among them, the gun type is more common, indoor and outdoor; the hemisphere type is generally used indoors, the volume is small, and it can be wall mounted or ceiling mounted.
For ordinary cameras without wide dynamic function, avoid direct light source, and do not install backlight, the principle and method of camera backlight compensation adjustment! The surveillance camera must be securely fixed during installation to prevent camera shake. For the wall, you can use the impact drill to hit the eye, plug the plug, and then use the self-tapping wire to fix the bracket to the wall. For the ceiling ceiling, you can put the wooden block on the top and let the self-tapping wire screw through the ceiling into the wooden block. There is a key issue: the choice of camera mounting brackets should also be noted.
Outdoors try to choose outdoor special brackets, it can't cost a few dollars, but the wind resistance coefficient is very different. The wireless bridge knows to use a thick bracket, while the camera chooses such a bracket, which is a little bit of wind and grass. The position immediately changed.
3, the installation height
The installation height of the surveillance camera should not be too low, to prevent malicious damage from others, nor too high, and it is not convenient for future maintenance. It is recommended that the installation height be three or four meters, you can get it by stepping on a ladder, and if the high pole is installed. The camera must be considered for post-maintenance. For example, it is possible to install ladders in the poles. It is a very expensive thing to rent a high-altitude work vehicle. At the same time, because the installation height of the surveillance camera is high, it is necessary to use auxiliary tools such as ladders. Therefore, it is necessary to pay attention to safety when climbing the ladder. In case of falling from high altitude, it is dangerous. For higher positions, be sure to fasten the seat belt before proceeding.
4, electricity safety
The surveillance camera needs to be powered separately. When performing strong electrical wiring, it should also pay attention to safety. It can be tested with a multimeter and a test pencil to ensure that the power is turned off after the power is cut off. Waterproof treatment, Zui is good to buy a network surveillance camera with a waterproof tail. Alternatively, install a small waterproof case under the surveillance camera and place the power supply and connectors in a waterproof case.
Pay attention to lightning protection and lightning-hit areas. Surveillance cameras must be protected against lightning strikes. Video lightning protection modules and power modules can be used for lightning protection.
There are two kinds of power supply modes: DC DC power supply and POE power supply. The PoE power supply is powered by the DC power supply. It only needs to be connected to the PoE switch or the PoE network hard disk recorder to supply power. The construction and maintenance are simpler and more convenient.
Non-PoE power supply: Each camera needs wires, network cables, PVC bushings, sockets, security power supplies... a lot of accessories, wiring is troublesome, installation is complicated, and maintenance is not easy.
PoE power supply: a camera with a network cable, data and power transmission at the same time, simple and convenient.
Compared with the two power supply modes, PoE power supply is more compact and the cost may be lower than that of non-PoE power supply.
5, the needs of the lighting environment
In order to avoid reflections and shadows when using surveillance cameras at night, lighting equipment is usually required, and infrared lamps can be used instead of ordinary light bulbs. However, users must use black and white surveillance cameras and network surveillance cameras with infrared lighting because black and white surveillance cameras are more sensitive to infrared light, while color surveillance cameras are not capable of infrared.
Nowadays, many cameras have begun to adopt wide dynamic functions to enhance their imaging capabilities in backlight conditions. However, this does not mean that the camera can continue to work in a strong light environment. Because under the glare of the strong light, the direct glare easily causes the camera to locate the accurate image normally, and finally the color filter on the sensor chip is decolorized forever, causing the camera to appear streak in the monitoring image.
Therefore, if possible, we should make the camera in a "smooth" mode as much as possible, but in any case, we must avoid direct stimulation of the camera lens by glare for a long time.
In order to monitor the night, you have to use IPC with good night vision. The night vision distance is mainly determined by the number of infrared lamps. The night vision distance of a single lamp is 30 meters, and the night vision distance of a double lamp is 50 meters.
6, cables and connectors
For network cameras, its line erection is obviously more abundant than traditional analog devices. However, no matter which transmission method is used, interference is one of the problems we have to pay attention to. Especially for the video signal transmitted by cable, the same direction transmission of the signal line and the high-power wire is undoubtedly a taboo in the wiring process, and it is not allowed to put the two in the same transmission line tube for the convenience of construction.
Even if you are unable to separate the two even if they are restricted by the environment, you must ensure a separation distance of at least half a meter. Only such a plan can better avoid the influence of strong magnetic interference on video transmission, but for devices using wireless signal transmission, although there are fewer restrictions on the line.
However, the camera itself should also avoid the surrounding sources of strong magnetic interference. At the same time, the camera is insulated from the ground. In addition, we must also pay attention to avoiding the influence and obstacles of the line on the work of the platform. Adopting oxygen-free copper 0.5 wire diameter national standard network cable, gold-plated crystal head, RVV 2*0.5 sheathed wire within 30 meters of power cable, RVV 2*0.75 sheathed wire for 30-50 meters, RVV 2* for 50 meters or more 1.0 sheathed wire, the threading pipe is generally made of PVC, if it is buried or explosion-proof, galvanized steel pipe is used.
7, the installation of equipment accessories
In addition to some of the complete aspects mentioned above, some of the camera's auxiliary equipment installation specifications are also part of our construction. For example, to make the installation position of the camera head, rack and other equipment meet the design requirements, the installation should be stable and stable, easy to operate and maintain. The back and side of the rack should be in line with the maintenance requirements; if necessary, we need to install a protective cover or temperature control device on the camera.
For the links with complex lines, we should also indicate the usefulness and characteristics of each line for future maintenance and grooming. The above mentioned are the key points we need to focus on when setting up a simple network monitoring system. . These aspects are obviously much simpler and more intuitive than some complex large-scale monitoring systems.
However, from a critical point of view, these can be said to be the lifeblood link that affects the quality of camera work. It must not be neglected. Only when we grasp the important but easily overlooked elements mentioned above can we enjoy it. More efficient and convenient network monitoring.
8, the actual installation experience operation
(1), DVR formatted hard drive is very slow, what is the reason?
This should be a hard disk problem, you can try to replace the hard disk.
(2) What is the reason for the old drop of the network camera?
Possible reasons include: unstable power supply; poor network contact; no network cable head; hardware equipment problems.
(3), network camera, serious, what is the reason?
Possible reasons include: camera code stream is too large; switch problem; NVR bandwidth is not enough.
(4) How to set the wall on the decoder?
You can enter the decoder address through the computer browser, enter the decoder's management interface to set up, or have settings through the IVMS4200 client software.
(5), how to connect the webcam alarm?
Need a camera that supports alarm input, "Alarm in" on the tail line of the camera
(6), how to connect the webcam audio?
A camera that supports audio, with the words "A in" or "Audio in" on the tail line of the camera
(7) How to calculate the power of centralized DC power supply?
The general camera is powered by DC12V. For cameras with infrared fill light, a certain amount of current redundancy is needed to prevent the camera from being powered insufficiently when switching to infrared mode.
9, how to add a video recorder?
(1) Automatically add, NVR automatically scans, you can display all online cameras, select “Add allâ€;
(2) Add manually, select the corresponding channel, and click “Edit†to input the relevant information of the camera.
10. How does the camera change the IP?
(1) Open the camera's management interface from the computer browser, find the network option, and fill in the address to be changed;
(2) From the NVR, after searching for the camera, click “Edit†to enter the changed address.
11, how to change the address code?
Network dome players generally do not need to change the address code. There are two ways to change the analog dome address code:
(1) Hard switch change, there is a corresponding DIP switch on the movement of the ball machine, generally binary, toggle switch, adjust to the required address;
(2) Software modification, through the preset position, call out the dome menu, which has the address code modification option, and enter the modification.
12. How to determine the number of millimeters of the lens?
In general, the distance required by the location is divided by 2 and then divided by 1000 to obtain the number of millimeters of the lens, and then the number of millimeters is appropriately adjusted according to the required angle of illumination.
The focal length of the camera lens is 2.8mm/4mm/6mm/8mm/12mm, etc. Each product series can choose the lens focal length, which can meet the shooting needs of indoor and outdoor environments. In general, the larger the focal length, the smaller the field of view and the farther the monitoring distance.
Put into the actual use scene, 2.8mm focal length is suitable for elevators, stairs and other relatively small environments, 4mm is suitable for meeting rooms, shops, slightly larger scenes, etc., but parking spaces, factory workshops, courtyards and other more open areas can be Use lenses larger than 6mm; the specific choice can be determined according to needs.
13. Where is the focus camera adjusted?
“FOCUS†and “ZOOM†on the side or the rear of the camera can be adjusted with a screwdriver.
14, how to choose the disk array?
First calculate the storage capacity required for all front-end camera images, divide by the capacity of a single hard disk, get the number of disk, plus the number of management disks required for RAID, the number of hot spares, and get the number of array disks.
15. How is the network dome controlled?
NVR, computer client, and network keyboard can control the network dome.
What is 16, 485?
485 communication interface A hardware description of the communication interface. It only requires two communication lines, that is, data transmission between two or more devices. This data transmission connection is a half-duplex communication method. A device can only send data or receive data. The 485 for security monitoring generally refers to the PTZ control interface. After the protocol and rate between the control device and the controlled device are set, the control operation can be performed.
17. How to configure the fiber according to the actual situation?
The fiber type and the number of cores are selected according to the total number of cores and the transmission mode required by the system optical transmission device. The number of fibers is determined based on the distance that needs to be transmitted.
18. How far is the fiber transceiver configured?
After the transmission distance of the network cable is exceeded (generally 100 meters), it should be considered to be transmitted by optical fiber.
19. How to debug the remote?
(1) In the main menu, enter the system settings - network settings - DDNS - enable DDNS check - select the appropriate domain name service station in the DDNS type - enter the user name, password registered in this wang site - OK.
(2) Enter the router that accesses the recorder's Internet access, find the “Forwarding Rule†option, add the forwarding port and save it.
20, 3 million camera one hour video memory is how much?
The 3 million camera 1 hour video storage takes up about 3G. According to the size of the code stream set by the camera, the required hard disk storage space will be different, but the difference is not large.
When 21, 3 million access to the 16-channel 2 million video recorder, the number of access roads needs to be halved?
The number of access channels of the network video recorder = the total bandwidth of the video recorder ÷ camera code stream, the larger the code stream, the fewer the number of access channels, the theoretical 3 megapixel camera is about 1/3 larger than the 2 million camera code stream.
22. How to choose the platform integrated machine and decoder?
The platform integrated machine integrates functions such as decoding, management, and splicing into one device. The decoder is only decoding, walling (splicing, screen segmentation), and can be selected according to the user's functional requirements.
23, the role of streaming media server?
When a large number of client goods WEB access surveillance cameras, the general video recorder can not withstand too much network pressure. At this time, the streaming media server needs to be forwarded to transfer the client's access pressure to the server.
24. Do I still need a video recorder when using a disk array?
The storage function of the disk array, the data is stored in it, and a storage server is needed to manage it. In general, there is no need for a video recorder for a disk array.
25. What is the difference between LED lights and dot matrix lights?
The two lamps are essentially the same, and the dot matrix lamps are more powerful and have a longer life than ordinary LED lamps.
26. What should I do if the IPC is not displayed online after it is added?
1. The IP address of the IPC is not in the same network segment as the NVR address.
2, the network connection is not smooth, check whether the 8 cores of the network cable are all tested.
27. Why use the mobile client software to preview the image black screen?
1 server device is not online
2 The client added the device incorrectly, and the IP address, port, username, and password are incorrect.
28, monitoring shows no monitor, how do you want to use your own desktop computer?
The RJ45 interface on the VCR is connected to the computer with a network cable, and the VCR image is accessed through the computer client software.
29, the video of the monitoring room, want to separate a part to another monitoring room to see, how to operate?
The analog system can distribute one signal to another monitoring room through the video distributor; the network system can connect directly to the network cable, and open the image to be viewed through the computer client.
30. When will the encoder be used? Is the encoder NVS?
The English name of the encoder: NETVIDEO SERVER (network video server) is also called video encoder, its function is to encode the analog camera video signal into a network signal. When the analog camera video signal needs to be connected to the network system, an encoder is needed.
There are two encoding standards supported by IPC and NVR: H.264 and H.265, which are next-generation coding standards that can compress video size to half of the former without losing image quality. With the same bandwidth, H.265 can transmit more HD video.
31. Is the encoder used inside the elevator? What are the pros and cons?
The encoder is used in the elevator because the accompanying cable in the elevator has only coaxial cable and no cable. When the market has a more economical and practical elevator cable, it is recommended to consider using a network camera. The high resolution of the encoder's zui is WD1, which is far less than the pixel height of the network camera.
32. How to arrange the power supply for the camera?
The so-called centralized power supply means that all front-end equipment is powered, and is provided uniformly from the back-end central control room. There are two situations:
1. Centrally provide the mains to the front end. The power adapter of the camera is placed on the camera. In this case, the power cable should be separated from the video signal cable. The power cable must be protected by JDG.
2. Centrally provide the DC power required by the camera to the front end, and the camera power adapter is placed in the back control room. In this case, the power cable and the video cable can share the same line. If the requirements are not strict, PVC can be used. tube. At the same time, pay attention to the relationship between DC transmission distance and wire diameter. The farther the transmission is, the larger the required wire diameter.
33. What is wide dynamic?
Wide dynamic technology is a technique that allows the camera to see the characteristics of the image under very strong fiber contrast. When a high-brightness area illuminated by a strong light source (daylight, luminaire, or reflective) and a relatively low-intensity area such as a shadow or a backlight are simultaneously present in the image, a bright area appears in the image output from the camera, and the exposure is excessive. White, while the dark area becomes black due to underexposure, which seriously affects the image quality. The camera has limitations in the performance of the brightest area and the darker area in the same scene. This limitation is usually referred to as the "dynamic range".
34. What are the factors that affect the stability of network monitoring and operation? Say the most common factors:
1. Network bandwidth and switch configuration.
2, the network cable, the quality of the transmission cable is good or bad.
3, the quality of crystal head and other auxiliary materials and the level of construction workers.
4. Selection of mainstream hardware, topology planning, comprehensive construction and testing of the project.