Designed to be used in sensitive and secret government projects in the mid-20th century, CCTV has come a long way since the days of television cameras and magnetic storage, which can be called primitive compared to today’s TV technology. CCTV was originally developed in the late 1970s and was initially limited to high-risk security applications such as banks. Today, there is a wide range of usage from retail to stadiums.
What is CCTV?
CCTV “Close Circuit TeleVision” is an abbreviation of the initials. CCTV stands for Closed Circuit Television. The CCTV system refers to a system in which the circuits in which the video is transmitted are closed and all elements (cameras, monitor monitors, recorders) are directly connected to the system.
The system is a circuit that cannot be accessed by anyone externally as in closed-circuit design and is different from terrestrial television broadcasting. Because the signals are not accessible to everyone. Video streams are only available to authorized users.
Compared to the silent, black-and-white low-resolution images of the past, today’s CCTV security systems are stylish, robust and handy, delivering highly detailed images. Early systems used analog magnetic tape technology (VCRs) with limited storage capabilities. The frame rate was low, the resolution was generally poor and there was very little detail. Since these cameras are usually black and white, it was not possible to identify facial features after examining the images, although you could see a thief attempting the attack.
Today’s advanced CCTV systems are very different from older CCTV systems thanks to advances in digital technology such as high resolution, wireless communication, digital optics, analysis software and digital storage options. Depending on the selected model, most of the new generation of high resolution cameras have IR technology for seamless transition to infrared for night vision. High-resolution images can now detect not only what color clothes a thief is wearing, but even the finest details of the clothing’s logo. With wireless communication, cameras can be accessed and controlled from anywhere in the world at any time via an application.
CCTV Application Areas Due to the decrease in the prices of camera systems and video recorders, CCTV security systems can now be seen everywhere from small businesses to homes. CCTV not only increases overall security, but also acts as a deterrent against anti-social behavior.
In CCTV security applications, the actual scope is almost limitless. The base is not only security, but CCTV systems can be adapted for numerous scenarios, such as production line controls in factories, traffic monitoring systems, hotels, stadiums, convention centers, sports facilities, private television networks that broadcast special events, and wildlife monitoring, for example, where conditions are not suitable for human intervention.
The CCTV system is often associated with high-end security cameras compared to consumer cameras. However, in practical terms, any home security camera system is also technically considered a CCTV system. Any camera that broadcasts a signal, wired or wireless, can be connected to a CCTV system. Systems range from a simple analogue package for small spaces to highly advanced digital systems integrated into access control and fire systems.
There are three basic elements to a CCTV security system. If we take a simple CCTV system, these are cameras, lenses and monitors.
The CCTV lens or lens allows the image to be transferred to the sensor. The lens to be used is determined by the camera and the characteristics of the area to be monitored. For a lens to be used in a camera, its format must be compatible. Depending on the connection type, the lenses are called C-Mount and CS-Mount.
The type of CCTV lens used varies depending on the area where the camera will be installed. There are basically four types of lenses. These;
– Fixed lenses cannot be adjusted to different positions for distance or lighting once installed. Costs are lower than other lenses. Fixed-lens security cameras are generally ideal for indoor use where lighting is consistent.
– Manual iris lenses can be adjusted for changes in lighting conditions, but adjustment is done manually.
– Automatic iris lenses can sense lighting changes in the area and automatically adjust to provide the best picture. They are usually the best choice for outdoor applications.
– Motorized lenses allow remote focusing.
A CCTV camera system can be designed to suit any scenario with a variety of equipment options from a wide range of brands. The cameras can be either internal or external, visible or hidden. The cameras can be viewed even when abroad with an internet connection.
The images obtained from the field are converted to video signals by the cameras and transmitted to the monitor and imaging is provided. The most basic CCTV system is established by connecting a camera and monitor with a coaxial cable. In such a system, the image is transmitted directly to the monitor without any switches or additional units in between. CCTV camera models are generally divided into color and black / white, but have a large number of options depending on usage. For example, a business may need a color camera during the day, but at night it turns black and white.
The CCTV camera can be used indoors or outdoors. When used outdoors, it always requires a protective housing. For indoor use, the environment or aesthetic constraints must determine whether a housing is required. Systems may include a combination of both fixed and moving cameras.
The PTZ function on CCTV cameras allows the camera to be remotely controlled and set for the desired area. It can perform horizontal (right and left) or vertical (up and down) movement depending on PTZ angle.
IP ratings in cameras indicate the resistance of cameras in any environment against water, moisture, snow, dust, temperature impact, tampering, etc. Some outdoor cameras can operate at temperatures ranging from -40 to 50 ° C.
Hidden CCTV Camera
The hidden CCTV camera can be integrated into appropriate parts of any CCTV network and is often used by most businesses. Hidden cameras enable the recording of criminals looking for security cameras. Thus, they may be more effective in capturing video evidence, but they are not deterrent to traditional CCTV cameras because they do not appear. At the other end of the spectrum is a fake security camera. These cameras are low cost and deterrent devices that often look like a CCTV camera with flashing lights. Many small businesses include counterfeit cameras as additional security measures to their systems.
One of the most important components of the CCTV camera system is the monitors. CCTV screen sizes vary according to the CCTV room / area to be positioned and the number of cameras. The cameras can be black and white or color. Televisions with a scart connection can be used for small-scale applications. However, the monitors produced for CCTV camera systems are manufactured according to the 24/7 operating principle to meet the system requirements. Therefore, it is more expensive than a standard television but more profitable in terms of investment cost.
CCTV Recording DVR
Since it is impractical to play back images 24 hours a day, the image taken by the camera must be recorded on the CCTV recording medium for later viewing if necessary. The CCTV recorder can be analog (DVR) or digital (NVR). CCTV recording The DVR device stores images such as a computer on the hard disk. Thus, images can be easily searched by event, time and date.
Besides DVR / NVR, videos can be recorded over ethernet or cellular networks (3G, 4G and soon 5G). The visual data is sent to the cloud by an encoding visual network adapter (VNA). A cloud-based management system allows the playback of video in real time or using the Internet. VNAs can also record to digital media, such as SD cards, as a precaution to the possibility of loss of ethernet or WiFi signal.
In applications where multiple cameras are used, a video switcher is included in the system. With the CCTV switcher, any camera can be selected to be held on the screen, or automatically set to display sequentially between all cameras. The switcher units are available in different models allowing connection of 4 to 16 cameras. Advanced display units such as Quad, Multiplexer or Matrix Switches can also be used to view or record cameras on a single screen.