Installing a video surveillance system with your own hands. Part I.
Installing a video surveillance system with your own hands. Part I
Where does this question come from? First of all, it is a simple desire to save on the services of installation organizations. Secondly, the presence of a huge flow of information on the Internet creates the illusion of simplicity and accessibility of independent installation. In addition, this is also facilitated by the appearance on the market of «ready-made» kits, consisting, as a rule, of a recorder and several video cameras with small pieces of wire. So, the components of the success of this event depend on the choice of the number of cameras and their installation location, as well as the choice of a video recorder and other peripherals.
Before you go on a trip to companies offering this equipment for sale, you need to understand for yourself what you want to get in the end, what the video camera will “see” and how useful this information will be.
The very first request, when contacting the manager of most clients, is this: pick me a video camera so that it looks at 50 meters and has an angle of 90 degrees. The funniest thing in this is that this question is asked by people who probably have both digital cameras and consumer video cameras at home, that is, they have looked into the camera viewfinder or LCD display more than once. It should be explained that now all video cameras and cameras, both for household needs and for video surveillance systems, «see» from half a meter to infinity, well, that's their depth of field. But the angle of view for video surveillance systems depends on the design features of the camera or lens and has either a fixed angle for cheaper models, or a variable angle within small limits on the camera itself. Fixed angles are in the range of 8, 12 16, 22, 32, 42, 62, 72, 92 – 104°, and with a variable angle of view from 8-9°. And the wider the angle of observation and the greater the distance to the observed object, the less space the objects will occupy on the monitor screen, that is, the smaller the scale of the resulting image will be.
For example: if the video camera will observe a distance of 100 meters along the front, then on the screen of a standard 19-inch monitor a car 4.5 meters long will occupy only 1.6 cm! Accordingly, there can be no talk of any recognition, not to mention a person, a car number or its color. Therefore, before going to the manager, you need to make a small preliminary calculation for yourself, at least the number of required video cameras, with the necessary viewing angles and ultimately get the picture on the monitor screen that will not disappoint with a small scale.
Links on the topic:
Installing a video surveillance system with your own hands. Part II
Installing a video surveillance system with your own hands. Part III
Installing a video surveillance system with your own hands. Part IV