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CCTV stands for closed-circuit television. It is a video surveillance system that uses cameras to transfer a signal to a particular place on a finite set of monitors. CCTV systems are used in various applications, including security, traffic monitoring, and retail loss prevention.
As you might know, CCTV cameras are typically mounted in public areas, such as streets, stores, and parking lots. They can also be used in private settings like homes and businesses. CCTV cameras come in various sizes and shapes and can be analogue or digital.
Well, there is still a lot to know about CCTV cameras, and I’ll help you learn everything you should be aware of. From the actual working procedure of a CCTV camera to its major types, a lot needs to be uncovered. Be with me in this guide to learn more about CCTV cameras!
For your information, the exact way that CCTV cameras work can vary depending on the camera type and the system it is part of. However, the basic principles are typically the same.
The primary objective of a CCTV camera is to capture light and recast it into a video signal. A CCTV camera captures a series of frames and then sends those shots to a monitor or recorder. The camera uses a lens to focus light onto a sensor, which transforms the light into electrical signals.
These signals are then handled by the camera’s electronics and converted into digital images. The images are then transmitted to the monitor or recorder, which can be viewed in real-time or stored for later playback.
CCTV cameras have several components that work together to capture, process, and transmit video footage. Typically, a CCTV camera comprises a camera lens, image sensor, digital signal processor (DSP), encoder, transmission medium, monitor, recording device, and power supply.
The following is a comprehensive recap of all the most common CCTV camera components.
The camera lens specifies the focal length, field of view, and depth of field of the camera. Different lenses can be used to achieve specific angles of view, such as wide-angle lenses for broader coverage or zoom lenses for adjustable focal lengths.
The image sensor captures the video images and sends the electrical signals for further processing. The two most common types of image sensors used in CCTV cameras are Charge-Coupled Devices (CCDs) and Complementary Metal-Oxide-Semiconductor (CMOS) sensors.
The DSP enhances the image quality, adjusts parameters like brightness, contrast, and colour, and applies other image processing algorithms to optimise the video output.
The encoder compresses the processed video signal into a specific format, such as H.264 or MJPEG. Compression reduces the file size of the video footage, making it easier to store and transmit over networks.
CCTV cameras use either wired or wireless transmission methods to transmit the video signal. Wired transmission typically involves coaxial cables or Ethernet cables, while wireless transmission utilises technologies like Wi-Fi or radio frequency (RF) signals.
The monitor displays the live video feed from the CCTV camera. It allows real-time monitoring and observation of the surveillance area. Monitors can be standalone displays or integrated into a control room or security centre setup.
The recording device captures and stores the video footage for later review or analysis. It can be a Network Video Recorder (NVR) or a Digital Video Recorder (DVR).
DVRs typically use hard disk drives (HDDs) to store the recorded footage locally, while NVRs store the data on network-attached storage (NAS) or cloud-based storage.
CCTV cameras need a power source to operate. They are usually powered by electrical outlets or, in some cases, by batteries or Power over Ethernet (PoE) technology.
The key differences between analogue and digital IP network cameras lie in how the signals are processed and transmitted. In analogue systems, the conversion from analogue to digital occurs at the DVR stage, while digital IP cameras convert the signal within the camera itself.
Additionally, digital IP cameras offer higher resolution and utilise Ethernet cables for network connectivity, whereas analogue systems rely on coaxial cables. Both systems have their advantages and are suited for different surveillance needs.
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 | Analogue Camera System | Digital IP Network Camera |
Signal Conversion | Analogue signal converted to digital at the DVR stage | Analogue signal converted to digital within the camera |
Transmission | Transferred via coaxial cable | Transmitted over a LAN using Ethernet cables |
Recording | Stored on a hard drive within the DVR | Recorded onto a Network Video Recorder (NVR) |
Resolution | Lower resolution compared to digital IP cameras | Higher resolution for good image quality |
Network Usage | Efficient use of network resources with a single IP address for all cameras | Each camera has its own IP address and data stream |
Remote Viewing | Can be viewed on monitors connected to the DVR or remotely on a computer screen via a network | Can be accessed remotely over the LAN or the internet for viewing |
Connectivity | Relies on coaxial cables for signal transmission | Utilises Ethernet cables (e.g., Cat5e) for network connectivity |
Flexibility | Limited scalability and flexibility in system expansion | Scalable system with the ability to add cameras easily |
PTZ cameras are commonly used in large areas or locations with potential blind spots. These cameras have the ability to pan (move from side to side), tilt (move up and down), and zoom in and out. This functionality helps identify the cause of an alarm activation by providing comprehensive coverage and flexibility.
Night vision cameras are effective deterrents for sites and properties left unoccupied at night. They can record the finest footage even in total darkness with infrared LEDs to illuminate the area. Many companies use night vision CCTV to enhance security during nighttime or outside operating hours.
Day/night CCTV cameras are designed to perform well in any lighting condition. They use extra-sensitive imaging chips to ensure clear footage, whether in bright sunshine or the darkest night.
These cameras are ideal for premises that require continuous surveillance without the need to switch between cameras or compromise image quality.
Dome cameras acquire their name from the dome-shaped case they have. They are commonly used in public transport and other locations. The dome design allows operators to discreetly point the camera in any direction without the subject being familiar.
These cameras can rotate 360 degrees, providing comprehensive coverage, and their high fixing location makes them difficult to tamper with.
Bullet cameras are instantly recognisable as CCTV security systems. They are resistant to dirt, water, and dust, so they are well-suited for outdoor positioning.
Bullet cameras serve as a perceptible deterrent, showcasing that the sites are under lookout. They can capture footage over long distances and are designed to operate in challenging weather conditions.
C-Mount cameras are similar to bullet cameras but have detachable lenses, allowing for adaptability in monitoring different areas and distances.
They are commonly used in the construction industry to monitor access points and roads. C-Mount cameras have weatherproof casings that can withstand extremely cold conditions.
IP CCTV cameras are linked via the internet, enabling remote access from anywhere. The video footage is compressed to limit bandwidth usage and ensure uninterrupted streaming. The recorded video is generally stored in the cloud for future access or on Network Video Recorders (NVRs).
Wireless CCTV cameras are convenient options for fast installation or security in remote areas without access to mains cabling or the internet.
These systems are quick to install, do not require drilling or piping, and allow for secure internet transmissions for remote management.
HD cameras address the issue of poor video quality found in cheap, low-quality CCTV systems. They offer crisp and clear recording resolutions, ranging from 720p to 4k. HD cameras provide detailed footage, allowing for better identification of faces, number plates, or actions.
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