Video surveillance via the Internet.
Video surveillance systems are confidently entering the global Internet.
Every day we receive orders for the construction of a video surveillance system with the ability to access and control via the Internet.
This is a fairly simple task for our specialists, but there are some difficulties beyond our control.
The main problem is the availability of access to the Internet, if for Kyiv and other large cities this is no longer a problem, then for suburban facilities connecting to the Internet with a stable and sufficiently high connection speed is a task that is sometimes impossible to solve for reasonable money.
But technology does not stand still, and especially data transmission technologies, and we always try to do everything possible to solve the problem set by the client. Thanks to this, our clients can remotely, from anywhere in the world where there is Internet, control their business using video surveillance systems.
Intelligent video surveillance systems
That's right — video surveillance is gaining intelligence.
And the intelligent functions of video surveillance systems provided by market leaders with each new line of equipment do not cease to impress. The opportunities provided today are already quite a lot.
A familiar motion detector for all video, which detects movement in the frame and creates a system event, which can be used to record and perform other functions in the system, but this function only appeared in digital video surveillance systems.
A video motion detector is currently present in every system, and this is understandable — all video surveillance systems today are digital.
However, such useful functions as monitoring the presence or absence of an object, tracking an object, determining the direction of movement of an object, monitoring the crossing of certain boundaries by an object, counting objects moving in one or different directions, face recognition, recognition of vehicle license plates, monitoring the speed of vehicles are available in fairly expensive video surveillance systems and are not affordable for every organization.
Video surveillance cameras
When choosing video surveillance cameras, many questions may arise, despite the fact that video surveillance cameras have long been presented on the market and are not something unusual.
First, you need to decide whether you need outdoor cameras or indoor surveillance cameras.
Outdoor surveillance cameras
Next, we decide on the temperature range for operating the camera.
If you plan to use CCTV cameras outdoors, the operating temperature range of the camera may be critical, for example, in the south of Ukraine the temperature rarely drops below -10°C, and in the central and other regions it can reach -30°C. In this case, it is important to know the operating temperature range that the CCTV camera can withstand.
Color or black and white: As you know, CCTV cameras are divided into color and black and white, and in the class of color video cameras there is also a subclass «day/night». Color cameras give a beautiful informative picture due to color, but they see poorly in low light conditions, for example at night.
Therefore, it is better to use them only where good lighting is guaranteed 24/7 or where it is necessary to use high-quality color surveillance cameras with a day-night function, such as SAMSUNG SCO-2080RP or Visionhitech VN70H-VFAIR, etc.
Black and white outdoor cameras usually see better than color ones in low-light conditions, and if there are no light sources at all at the object of surveillance, even background ones, then with black and white you can use IR illumination and IR spotlights, the light of which is not visible to the human eye, but is very clearly visible to surveillance cameras.
Day/night class CCTV cameras operate in color mode in good lighting conditions, and when lighting conditions decrease, for example at night, the cameras switch to black and white mode.
Such cameras see better in the dark than regular color cameras, but somewhat worse than black and white cameras with a sensitive matrix, but with day/night cameras you can use IR illumination.
A few words about choosing a lens for outdoor CCTV cameras. Lenses with automatic aperture control (AAC) are especially relevant for outdoor video cameras. A lens with AAC works like a human pupil — the aperture closes when exposed to bright light and opens wide in the dark.
This is done so that the image always remains clear and the camera does not «go blind» from bright light.
In CCTV cameras with lenses without ARD, this work is done by electronics and usually does a good job, but still, if direct sunlight or other bright light sources can enter the camera, it is better to choose outdoor cameras with ARD lenses, despite the fact that such cameras are somewhat more expensive due to the complex ARD mechanism.
Distance from the camera to the observation or recording point.
Outdoor cameras are often used at a distance from the place where their video signal arrives.
It is necessary to remember that without amplifiers, a black-and-white video signal can be transmitted over a distance of up to 500 meters via a high-quality coaxial cable, and a color signal – up to 300 m.
If the distance is greater, then video signal amplifiers or, for example, devices for transmitting video signals via a «twisted pair» will be required.
Vandal-proof or of conventional design.
We do not live in an ideal world, and it is quite possible that someone will want to break or turn your video camera. To prevent such cases, special «vandal-proof» video cameras will come in handy.
INDOOR CAMERAS
Here, as with outdoor cameras, you need to understand whether you need black and white cameras that see better in the dark, or color cameras that provide a beautiful image, or even more expensive day/night models.
The temperature range and distance to the point of receiving the video signal indoors are not so important. Here, the quality of the received image and the design of the surveillance cameras rather come to the fore.
There are several main options:
Standard design cameras without a lens are fairly large «brick» shaped cameras with a lens screwed onto them. Such cameras are convenient when you need to individually select a lens with the required characteristics.
By the way, such surveillance cameras can also be used outdoors — special hermetic housings are used for this.
Miniature surveillance cameras are cylinders or squares.
Dome cameras are surveillance cameras in hemispherical housings.
Of all video cameras, these look the most concise and neat.
Dome cameras can be of normal resolution and sensitivity, or high.
GENERAL QUESTIONS
Viewing angle and viewing distance of CCTV cameras.
Often you need to see people and their actions, often you need the ability to identify a particular person. To do this, it is important to choose the right viewing angle for the lens. Everything is much simpler here than it may seem.
Any lens has a characteristic such as focal length, which is expressed in mm, for example, a lens with f=3.6mm has a horizontal viewing angle of 78° (for a 1/3” matrix). The shorter the focal length, the wider the viewing angle and the smaller the objects will appear on the screen.
There is a simple rule for selecting a lens: you will see a person in full growth on the screen at a distance equal to the focal length of the lens in meters, and you will be able to see a person’s face well at a distance 2 times shorter than the focal length of the lens in meters, and if you just need to notice if there is someone in the camera’s field of view, the camera will allow you to do this at a distance 5 times greater than the focal length of its lens.
For example, if you want to see a person’s face at a distance of 8m, you need a lens with f=16mm, and if you want to see exactly what people are doing at a distance of 25m, you need a camera with a lens with f=25mm, if you just need to notice people at a distance of 25m, then the option with f=5mm will do. By the way, a very convenient solution is CCTV cameras with varifocal lenses, the viewing angle of which can be changed in within certain limits right on the spot.