Frequently Asked Questions for CCTV
What is the difference between an IP CCTV camera and an analog one?
The main fundamentally important difference between an IP camera and an analog one is the conversion of the signal of the photosensitive matrix into a digital data stream. This is done by the built-in hardware encoder. The main feature of the analog signal is that it is transmitted strictly from the matrix to the receiver, for example, from the antenna to the TV. No feedback. The main methods of video compression in IP cameras are MJPG, H.264, MPEG-4. There are several representatives of IP cameras that transmit video without preliminary compression.
Why switch from analog video surveillance to IP video cameras?
The company has switched to digital data transmission in such fields of activity as television broadcasting, communication means, copying devices, information security for a long time, and video surveillance is no exception.
There is one explanation for this: digital signal processing is simple, and information is more easily stored and reproduced.
What is a camera lens?
A lens is an optical system consisting of lenses. Its function is image transmission. Since the role of the lens for organizing high-quality images is huge, then you need to choose a video camera for a specific object carefully.
How to get sound along with video from surveillance cameras?
An analog camera usually does not have a built-in microphone. To ensure sound transmission, it is necessary to install an additional microphone and route the wire to the DVR. In contrast, a digital IP camera is usually equipped with a built-in microphone. Many IP cameras also have a built-in speaker. In them, sound is transmitted in both directions and it is possible to use it as an intercom.
What are CMOS and CCD?
CMOS (complementary metal oxide semiconductor) is a matrix that allows the production of sensors with a large number of pixels.
CCD (Charge-Coupled Device) - a feedback charging device (CCD).
CMOS matrices are cheaper than CCD and are not able to provide high-quality images.
Today, CMOS matrices have undergone significant changes and meet all the requirements that apply to video surveillance systems.
What is permission?
Any camcorder has such an important component as resolution. This parameter is responsible for the ability of the surveillance camera to clearly reproduce the smallest details. The higher the resolution, the clearer the picture obtained from the camcorder. Resolution of IP cameras is a product of pixels vertically and horizontally of a matrix.
Camcorders with one resolution are able to produce images of different quality, since this parameter is not related to the physical resolution of the matrix, color reproduction and its other features. If you compare the quality parameters of the matrix, you should pay attention to the resolution in TVL (television lines). This criterion indicates the number of lines that can be seen in the picture.
Typically, 400 TVLs are sufficient for a video surveillance system. A resolution of more than 500 TVL allows you to see the smallest elements (facial expression, car number).
What is the photosensitivity of a matrix?
Photosensitivity determines the degree of reaction of the matrix to illumination indoors or outdoors. A high-sensitivity sensor requires less light to produce high image quality.
Black and white contrast vision is sometimes better than color. Therefore, at night, the camera automatically switches to black-and-white mode. At the same time, IR illumination can be turned on so that the resulting image is even with higher quality. Even in complete darkness, such cameras remain effective.
To measure the illumination using the value of Lux.
Examples of illumination values:
Moonless night: 0.01 lux
Moonlit Night: (1/4 of the Moon): 0.05 lux
Starlight Night: 0.003-0.1 lux
At night on the street with the full moon: 0.3-0.1 lux
Deep Twilight: 1 lux
The auditorium in the theater: 3-5 lx
Twilight and illuminated highway at night: 10 lx
Warehouses: 75-30 lux
Offices: 50-500 lux
Hotel halls: 100-200 lx
Shops and supermarkets: 1500-750 lux
Daylight on the street in cloudy weather: about 5,000 lux
Daylight on the street in sunny weather: 100000-5000 lux
The ability to "see" the camera, in the description of its properties by the manufacturer, implies a minimum level of illumination of the studied object or subject. However, high image quality is not guaranteed. Therefore, according to the photosensitivity parameter, you should (when choosing) choose a camera that will exceed the illumination level of the investigated object several times.
What is matrix size?
A fraction with a dimension in inches characterizes the size of the matrix (1/4, 1/3 and 1/2) for photo and video equipment. The higher the size of the matrix, the higher the image quality. It means. That when the camera's matrix is ½ inch, the image on it will be higher quality than those that have ¼ inch.
Cameras for more accurate images of objects in low light conditions are an order of magnitude higher and in price. A significant role in pricing and increasing prices is played by the high cost of the lens.
The concept of "day / night."
Progress in the indicative color segment has spawned regression as a function of camera photosensitivity. This means that contrasting vision in black and white is sometimes better than color. Therefore, at night, the camera automatically switches to black-and-white mode. This was one of the significant steps to get rid of the low light-sensitive mode in night vision.
What compression formats do IP cameras use?
Many cameras can handle the reduction of the file size of the broadcast video stream.
Such functions in cameras are performed by encoders and decoders. With their skill they can properly "deploy" the encoded signal. In IP surveillance by cameras, such compression formats as M-JPEG, M-PEG-4 and H.264 are common.
What is H.264?
Consider one of them (H.264) - an evolutionary species from M-PEG-4. The superiority of the evolutionary form of H.264 is that today it "works" on television (HDTV), showing high definition, and is much better than its predecessors, achieving the clarity quality of its improved function - increased stream compression. There is a smoother transition of colors, and a clear transfer of small details. Another advantage of the improved compression is the free up space for collecting archives by 30%, which is significantly higher than the M-PEG-4. The freed up space on the hard disk is an additional place for a video recording surveillance system, which often becomes a limiting factor in the registration of video surveillance.
How are IP cameras powered?
12 volts - power for most IP cameras. It can be provided with either a conventional power supply or with an Ethernet cable with PoE standard. This allows you to use the camera where the supply of other power is completely absent.
For IP cameras with PoE, there is a limit in the range of 100 meters from the power source. When you connect all the cameras to the PoE switch, it becomes possible to provide electricity to the entire CCTV system - connected cameras.
What is an IP address?
The unique code (identifier) for connecting the device on a local network or in the global Internet is called an IP address. Each camera, when connected, immediately gets its IP address (when changing the network, the network identifies it with its new, different address from the old one) and allows you to identify equipment every time you reconnect. For example, the IP address can be equal to 192.168.10.10, and when changing the network, for example through a VPN, give another address.
How to connect an IP video camera to a computer?
Usually a cable with an RJ-45 connector of the desired length or Wi-Fi is used.
Use this cable to connect the computer and cameras to the network according to the camera's instructions.
The next step is to configure all connected equipment with further software installation.
How to connect an IP camera to a local network?
If you already have a network, just connect to the Ethernet switch using any empty slot to connect.
Then the equipment is connected to the laid cables, the switch is turned on, and the network properties of the cameras are configured.
How to connect to the IP camera via the Internet?
It is important that, if desired, you can view the operation of cameras from anywhere in the world. So you can control what is happening in the house, office, warehouse, anywhere. To do this, you must configure the network parameters of the equipment used to receive information from IP cameras by entering the IP address of the cameras and using software or special mobile offers to configure network parameters and remote access.
What is AHD technology?
The development of technological progress continues. IP technologies are being improved by digitization, and AHD technology is a modern video surveillance technology with lower cost and improved video stream quality, comparable to the use of digital IP technologies. AHD cameras are now replacing old analog cameras.
A distinctive feature is higher quality at a low cost, which allows you to use the same cable networks and upgrade the old analog system to an AHD system.
What are the benefits of AHD technology?
Some advantages are listed below:
Using a conventional coaxial cable, AHD cameras transmit information to the recorder at a distance of 5 times than that of older analog cameras.
AHD equipment provides a resolution of AHD-M - 1280x720 (720p) and AHD-H - 1920x1080 (FullHD).
Among other advantages are no less significant:
-Easy to build a video surveillance system;
-similarity in many respects with the functionality of IP-systems;
-no delay in signal transmission;
-low AHD requirements for coaxial cable;
- AHD equipment forms a progressive scan, which gives a stable image on the monitor.
- compatibility with IP equipment and possible collaboration, where the work of these devices can be used, being with each other in different percentages.
AHD recorders are compatible with conventional analog cameras and can be a hybrid solution with the ability to connect IP cameras. Such recorders are also called hybrid.
What is a multi-format camcorder?
The multi-format (hybrid) camera is a high-resolution video camera compatible with various types of equipment (AHD, TVI, CVI).
The hybrid camera is compatible with cameras of its kind and finds a common language with cameras of other formats. For example, a camera that supports AHD and TVI format can work with the same DVRs.
If we simulate a situation where there is already installed video surveillance, which includes a DVR from the manufacturer HiWatch, working with the TVI format, then we can say with confidence that here you can install a multi-format camera that supports the TVI format.
This indicates that the process of modernizing video surveillance through the use of multi-format cameras, the hallmark of which is combining with other video surveillance systems, has been greatly simplified.
Summing up, it can be noted that the era of new technologies continues, and video surveillance systems not only operate, but also successfully interact with each other.