Do-it-yourself video surveillance system installation. Part I

Where does this question come from? First of all, it is a simple desire to save on the services of installation companies. Secondly, the presence of a huge flow of information on the Internet creates the illusion of simplicity and accessibility of self-installation. In addition, this is further 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 in their installation location, as well as the choice of the DVR and other peripherals.

Before you go on a trip to the companies offering this equipment for sale, you need to understand for yourself what I 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 up a video camera for me so that it looks at 50 meters and has an angle of 90 degrees. The funny thing about this is that this question is asked by people who probably have both digital cameras and household video cameras at home, that is, they have looked into the camera viewfinder or LCD display more than once. It is necessary to explain that now all video cameras and cameras, both for domestic 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 can be changed within small limits on the camera itself. Fixed angles are in the range 8, 12 16, 22, 32, 42, 62, 72, 92 – 104°, and with a variable viewing angle from 8-9°. And the wider the viewing angle 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 a video camera observes a distance of perhaps 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 question of any recognition, let alone a person, a car license plate 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 its small scale.