Video surveillance via the Internet
Video surveillance systems are confidently entering the global Internet.
Every day we receive orders to build 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 Internet access itself; if for Kyiv and other big cities this is no longer a problem, then for suburban properties connecting to the Internet with a stable and sufficiently high connection speed is a task that is sometimes impossible to solve for a reasonable price.
But technology does not stand still, especially data transmission technology, 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 an Internet connection, monitor 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 never cease to impress.
The opportunities provided today are no longer small. A motion detector familiar to all videos, which detects movement in the frame and creates a system event that can be used to record and perform other functions in the system, but this function appeared only in digital video surveillance systems.
Video motion detection is present in every system today, 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, facial recognition function, license plate recognition, vehicle speed control are available quite expensive CCTV systems are not affordable for every organization.
CCTV cameras.
When choosing CCTV cameras, many questions may arise, and this is despite the fact that CCTV cameras have been on the market for a long time and are not something unusual.
Initially, you need to decide whether you need street cameras or indoor surveillance cameras.
Street CCTV cameras.
Next, we determine the temperature range of the camera’s operation.
If you plan to use CCTV cameras on the street, 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 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, video surveillance cameras are divided into color and black-and-white, and in the class of color video cameras there is also a “day/night” subclass.
Color cameras provide a beautiful, informative picture due to color, but they do not see well in low light conditions, for example at night.
Therefore, it is better to use them only where round-the-clock good lighting is guaranteed or where it is necessary to use high-quality color surveillance cameras with a day-night function, for example, such as SAMSUNG SCO-2080RP or Visionhitech VN70H-VFAIR, etc.
Black and white outdoor cameras
They usually see better than colored ones in poor lighting conditions, and if there are no light sources at all on the object of observation, even background ones, then with black and white ones 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 video surveillance cameras operate in color mode in good light conditions; if light levels decrease, for example at night, the cameras switch to black and white mode. Such cameras see in the dark better than conventional color cameras, but somewhat worse than black-and-white ones 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.
Especially for outdoor video cameras, lenses with automatic iris adjustment (ADA) are often relevant.
A lens with an ARD works like a human pupil — the diaphragm 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 is not “blinded” by bright light.
In video surveillance 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 may enter the camera, it is better to choose street cameras with an ARD lens, 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 must be remembered that without amplifiers, a high-quality coaxial cable can transmit a black-and-white video signal over a distance of up to 500 meters, a color one – up to 300 m.
If the distance is greater, then video signal amplifiers or, for example, video signal transmission devices over twisted pair cables will be required.
Vandal-proof or a conventional design.
We do not live in an ideal world, and it is quite possible that they will want to break or turn your video camera; to prevent such cases, special “vandal-proof” video cameras will be useful.
INDOOR CHAMBERS
Here, as well as for street cameras, you need to understand whether you need black and white CCTV cameras that see better in the dark, or color CCTV cameras that give beautiful images, or even more expensive day/night class models.
The temperature range and distance to the video signal reception point indoors are not so important. Here, the quality of the resulting image and the design of the CCTV cameras 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; these cameras are convenient when you need to customize a lens with the desired characteristics for them. By the way, such video surveillance cameras can also be used on the street — special hermetic casings are used for this.
Miniature CCTV cameras — cylinders or squares.
Dome cameras are surveillance cameras in hemispherical housings. Of all the video cameras, these look the most concise and neat.
Dome cameras can be either normal resolution and sensitivity, or high.
GENERAL QUESTIONS
Viewing angle and viewing distance of CCTV cameras.
It is often necessary to see people and their actions, and the ability to identify a particular person is often necessary. To do this, it is important to choose the correct viewing angle of the lens.
Everything here is much simpler than it might seem.
Any lens has such a characteristic 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 objects will appear on the screen.
There is a simple rule for selecting a lens — on the screen you will see a full-length person at a distance equal to the focal length of the lens in meters, and you can get a good look at the person’s face at a distance 2 times less 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 an 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 within certain limits right on the spot.