CCTV Systems

CCTV Systems

One of the systems created today to control and monitor the living and working environment as well

Security and comfort are most commonly used in CCTV systems, or CCTV systems. These systems are also referred to as video surveillance systems or sometimes CCTV equipment. Depending on the settings on the cameras

And other equipment can be done. These systems are in different weather conditions and have good performance day and night. Some of the places where these systems are used are as follows:

Banks Schools & Universities Factories Department stores, department stores

Such as gold shops, supermarkets – on the roads and streets to control traffic – parking lots – public places such as airport halls, railway stations and city trains, etc.

Therefore, the use of CCTV systems is growing day by day and according to

Its manufacturing technology, which is based on the electronics and computer industry

The production of equipment for these systems is constantly evolving and progressing, and we try in this brief

We have provided the general principles and general facilities of these systems for informing and familiarizing students

Dear, let’s present.

Principles of operation of CCTV systems

The general working principles of CCTV systems are that first the images by

The cameras are then prepared and transferred to a monitor or TV for display and playback.

Also to record or change the way it is displayed on the monitor and simultaneously play back the images of the cameras

There is also equipment and facilities on the monitor and remote control of the cameras. According to the possibilities

Available on CCTV recorders capable of moving within range

Under the supervision of a warning and alarm system or stimulated by special sensors

And start recording videos from the place. To control the entry and exit of people to a place and for

Control large areas with multiple cameras and simultaneously display their image and audio-visual monitoring from a distance via local area network (LAN) or telephone lines without the need for physical presence of the controller

In places and in devices that have not been visually controlled by humans or

Surveillance camera systems based on how the image captured by the camera is sent

The control center can be divided into the following types:

Systems that transmit the image by coaxial wire (coaxial cable).

These systems are the least expensive type in terms of equipment cost, but in their implementation

Wiring problems and the problem of image quality loss at long distances (more than 300 meters) and in

The result is a sending distance limit. The following figure shows an example of these systems

Gives:

Example of a system that transmits an image by coaxial wire (coaxial cable)

Systems that transmit images wirelessly. The cost of running these systems

Due to the use of antennas and equipment, radio receivers and transmitters are higher, but

The problems of the previous type of systems have been solved to some extent. In the figure below in

Some parts of the system use wireless equipment:

CCTV systems can be a combination of wireless and wired systems

Design and implement.

Surveillance camera equipment

The following equipment is commonly used in CCTV systems:

Camera

MICROPHONE

Power supply

Image display (TV or monitor)

Camera Housing

Camera stand (Mount- Bracket- BASE)

Controller

Image Selector (Switcher)

Quad

Recorder

We now turn to a detailed description of each of the above sections:

Camera

Cameras used in CCTV systems in different types and with different possibilities

Made and commonly known as CCTV Camera.

The main function of the camera is to generate a video signal from a controlled location to send or display

Monitor or TV.

Types of cameras

Types of cameras used in CCTV systems in terms of application and

The possibilities are as follows:

* Pinhole cameras

These cameras image through a small aperture on the front of the camera

They take. Because of their small size and the possibility of hiding them more as a hidden camera or

Used for espionage purposes. These cameras are also available wirelessly

You can see an example of this camera below:

Some of these cameras are for hiding inside alarm or detector detectors

Fires are embedded. You can see examples of them in the following figures:

Mini cameras

Small and inexpensive cameras are more common in CCTV systems

Small are used. Most have fixed lenses and their image output is used. One

Examples of these cameras can be seen below:

The following figure shows the power input and output of the camera’s audio and video:

Industrial cameras:

In these cameras, features such as interchangeable lenses and the ability to adjust the lens and aperture and

There are image quality adjustment keys. You can see the image of the industrial camera below:

 

Some industrial cameras have the ability to adjust the lens in terms of magnification (zoom) and image resolution (focus) by

They have a controller, which is shown in the following examples of this type of camera:

 *

Night vision cameras:

These cameras have an optical sensor (photocell) to detect ambient light and when it is dark

The air emits infrared LED lamps that emit infrared rays and

They also provide the ability to shoot at night for the camera. The figure below shows these two parts

On the camera:

 

It is usually not possible to change the lens on these cameras, but it is possible to apply settings on the lens

And the image quality is present in some models. The construction of these cameras against water penetration and

Moisture and dust are protected and can be installed outdoors

They are installed on the ceiling and wall. The following is an example of these cameras

You see

:

*

Fixed ceiling (DOM) and fast (Speed ​​Dom) cameras

These cameras are mounted on the ceiling or on a hanging base. If

They have a controllable base that allows the camera to move quickly throughout

Directions that provide 360 ​​degrees are called fast ceilings. The possibility of adjusting the lens in terms of

There is also the distance and amount of ambient light in these cameras. Control of these cameras by the device

The controller or recorder or using special software on the computer.

* Wireless cameras:

These cameras have a transmitter (TX) inside the camera and a separate receiver (RX)

Depending on the power of the transmitter in a certain range, they can capture the image without the need for wiring

The image below shows some of these cameras with the receiver

:

*

Motion Detection Cameras (MAD)

These cameras are designed to start moving in the environment

They film. In the figure below, two types of eyes detect motion with a camera

It is given to start when the camera moves and bring the image to the device

The recorder sends:

 

Other types of cameras also capture images in their internal memory. In addition

It is also possible to transfer the image from the camera with a mobile phone SIM card via MMS. One

You can see an example of this type of camera below

:

*

Nested cameras:

These cameras are installed inside the front door of apartments, suites and private homes.

It is necessary to explain that a camera may have several types of features, for example

Has night vision and wireless or has the capabilities of industrial cameras.

Different parts of the camera

The camera consists of 4 main parts:

1- lens

2- Image sensor

3- Electronic circuit

4- Connectors

We will now describe the above sections:

1- Camera lens

In the camera, the passage of light into the camera and its features affect the quality of the image created

This part includes the lens and the light passage valve and to this set

The so-called camera lens. Depending on the type of camera and the facilities required and the location

Installation Different lenses are used on the cameras. Lenses are available at focal lengths

2.5, 8.2, 3.5, 4, 6, 8, 12, 16, 25, 35, 50 and 75 mm are made. The greater the focal length of the lens, the greater its magnification. Telephoto lens

This lens shows distant objects closer and better, but instead offers a smaller viewing angle. Conversely, the smaller the focal length of the lens (Wide lens), the better the close-up images are.

Its viewing angle is wider. For example, the focal length of the human eye lens is 17 mm and its viewing angle is 30 degrees. While a lens with a focal length of 4 mm and a viewing angle of 62 degrees.

The IRIS is responsible for determining the amount of light passing through the lens into the camera.

In the dark, the aperture should be larger to allow more light to enter the camera

In bright environments, to prevent the image from turning white, the aperture should be reduced to allow less light to pass through.

With luck