📹 How to choose a camera for observing: features, review of models

What is a video surveillance system

The simplest video surveillance system can consist of only one chamber. For example, Car DVR - the easiest sample standalone surveillance system with recording.

For observation of the organization of large territories - shopping centers, industrial sites and construction sites system may be a camera with the central circuit node. Most often, the central unit - it's just a computer with the connected cameras. In any case, even in the most complex configuration, the camera is the main component, which determines the quality of the resulting image and reliability of the monitoring system as a whole.

How to choose a camera for video surveillance

Cams differ more base parameters which determine the system performance, reliability, and its ultimate cost. These parameters are most relevant when you need to scale the existing surveillance system. And to know that it is necessary to connect and what is not - it is crucial.

By type of signal transmission

This test is very complicated and intricate. Already invented a lot of different standards, algorithms and approaches by which the signal is transmitted. Well, let's deal.

Submitting the video in two main ways: digital and analog. When the transmission analog image is converted into an analog signal that is constantly changing with time in a certain range. For clarity, most often it appears in the form of a sine wave. The simplest example - analog TV, which we used to be able to take any antenna.

The digital signal is transmitted via the sequence of codes separated by time. This is a more modern type of data transfer which is capable of producing high quality and scaled for any needs. IP-cameras work by such principle. In fact, when talking about digital video, most often have in mind them.

Until recently, analogue transmission method of slowly fading since ceased to meet modern standards of quality video. For example, he could not transmit a signal in HD, of Full HD and even more 4K. However, in the world there is still a lot of video surveillance systems, the entire infrastructure that is built on an analog transmission. Therefore, the new high-definition formats were created. Now the market is dominated by three major standards: HDCVI, HDTVI and AHD.

First - the development of Dahua, completely closed technology based on quadrature amplitude modulation with the separation of luminance and chrominance. Because the format is patented, to begin to produce compatible hardware, you need to be licensed developer. And this affects the final cost of the product and, in some way, limits the possibilities of expansion of surveillance systems.

HDTVI - an open standard with restrictions. As HDCVI division uses the brightness and color, but the algorithm to eliminate noise and increase clarity has development company Hikvision. Actually, it is mainly responsible for promoting and format. Interestingly HDTVI its hybridity - you can use IP-cameras and analog in the overall system. However, you will need a hardware encoder, which will make additional costs.

AHD - very open format of all. Moreover, it can simultaneously work with all types of equipment - a simple analogy, a number or an analog high-definition. That is, this technology is free - the best solution for the system, which is expected to continuously expand and modify.

With the advent of analog high-definition picture quality technology it has become almost equal between analog and digital.

On-site

The cameras are intended for external use, it is equipped with special protective covers which protect from the harmful effects of rain, temperature and sunshine. For very low temperatures embedded heating mechanism can be used. But for the premises, you can buy a simple model of the device.

By type of housing

housing types, there are many, each of which is designed to solve narrow tasks.

Here is a small list of the main types:

• modular. It is simply a camera module, which is available in any model with the body. This type offers a great opportunity for integration in almost every available or only to create a system. In fact, it is part designer, that can be connected to anything - home surveillance, videoglazki, observation of the outer perimeter;
• Bullet cameras. Have a ready housing and mounting system, mainly, to the ceiling. They can be fitted with a protective cover from the rain. The attachment mechanism allows to establish the desired fixed angle;
• Dome. It looks like a half-sphere made of plastic, with a ballpen inside the camera module. They often can be found in the hallways, and other indoor spaces;
• peephole. It has the shape of eye. Designed for installation in the input groups of buildings. Usually it has a large viewing angle, but it greatly distorts the picture, like a regular peephole;
• Vandal-proof camera. Generally have a spherical shape, a fortified enclosure, protected from physical and environmental influences. Mounted in areas with large concentrations of people. Capable of withstanding significant physical impact;
• fake. An interesting solution when you need to prevent illegal actions, but at the same time, I want to save. Waxwork at a distance virtually indistinguishable from the original camera. He will make the offender consider whether to do something illegal.

in functionality

Probably the most interesting criterion. There are plenty to choose from as well as the functionality may be present very different. This could include support for Wi-Fi, built-in modems for wireless transmission over mobile networks, autonomous recording on a flash drive or the presence of motion detection. In general, the degree of functionality generally ranges convenience. Naturally, the more functionality, the more expensive the camera.

According to a monochrome or color mode

Black-and-white camera cheaper than their color counterparts and are used in systems where the important fact of the presence or movement of penetration, and the color is not critical. They can also be used for shooting at night, as in the infrared mode, still there is no color.

Color should be installed where color matters. For example, in the parking lot, to determine the color of the vehicle to identify it if necessary. Therefore, the scope of application in the selection should also be taken into account. This will save and choose the best option of the camera.

The quality of the image

On how quality surveillance camera transmits the image depends on how accurately you can identify the object or the identity of the offender. Despite the fact that quality is considered to be resolution of the camera, it is not so. Quality - a combination of several parameters. We will list them:

• resolution. Today, even children know that such a permit or the notorious "megapixels." This is the number of points at which the camera can transform the image. It is logical that the higher the number - the higher the quality and picture quality. Limiting resolution analog high definition cameras - 1920 × 1080 megapixels. Digital also can transmit a full 4K;
• photosensitivity. An important parameter for day and night surveillance. If it even easier, the sensitivity is understood under the minimum amount of illumination to the camera can display the picture. Usually in model specification it is measured in Lux. The relationship is inversely proportional - the lower the number, the greater the range of day-night camera can shoot. For example, 20,000 lux corresponds to about a cloudy day, and a clear, moonless night - 0.001. That is, if we need to monitor only during the day, you can choose the model of 100 lux. In general, there are solutions to established IR emitters and a special filter on the camera, which provide a good picture even in total darkness;
• the dynamic range. Most often abbreviated WDR. A device that supports this technology can automatically adjust the levels of black and white colors in the picture with their high difference. That is, if the image will be areas with bright white and dark black, the WDR will align them in such a way that the details and the black and white will be clearly distinguishable.

Popular models of camcorders for streets

Among similar models on the market you can find products and from well-known brands, and from the little-known Chinese companies.

The first is typically a high-quality and tested devices, the reliability of which the manufacturer can guarantee. Naturally, they are more expensive. Chinese counterparts - it is almost always a cat in a bag. How much and how will last this camera is unknown. But their value is always a pleasant surprise.

Hikvision DS-2CD055FWD-I

An interesting model for the organization of a full day and night surveillance. Since the digital device, its maximum resolution is 2560 × 1920 pixels. In this mode, the camera can record video at 20 frames per second in a single stream. By the way, about flow - the most they can be 3. For image enhancement technology meet additional WDR, BLC and 3D DNR. The transition from night to day mode automatically. To connect the provided RJ-45 interface. You can also record data on a microSD flash card with capacity up to 128 GB. As part of the chamber is a smart analytics, enabling to detect the intersection of the permitted areas, as well as to recognize faces in the frame. The camera can work in conditions of temperatures from -40 to + 60C. The approximate cost of the camera is about 12,000 rubles.

Hikvision DS-2CD055FWD-I

Dahua DH-SD22204T-GN

Digital video camera in a protective case with a hemispherical twist mechanism. The maximum resolution is 1920 × 1080 mega pixels at 25 frames per second. Faster video to 50 frames per second can be obtained only at a resolution of 720 p. The camera is equipped with IR filter and has a high sensitivity, which allows to obtain an excellent picture even in the dark. From functional can provide an opportunity to shoot a panoramic tilt. For remote monitoring applications are available for Android and iOS platforms. Chamber cost is 14400 rubles.

Dahua DH-SD22204T-GN

HiWatch DS-I103

You can say budget camcorder for home use. its cost is relatively low - 4300 rubles. For the money the user will receive good dome camera with a maximum resolution of 1280 × 720 pixels. Broadcast may go into two streams - a main maximum resolution at 25 frames per second and optional - in 640 × 480 megapixels. Modes, day and night can be switched either automatically or on a schedule. The camera is able to respond to the motion. Connection is possible via Ethernet interface. Permissible temperature range - from -40 to + 60C.

HiWatch DS-I103