CCTV Systems

What is CCTV?

Closed Circuit Television (CCTV) is a system in which all elements – from the cameras to the recording devices – are directly connected in order to keep the video from being broadcast over public airwaves and on a closed circuit (hence the name). Since its development in 1942, CCTV has undergone drastic changes. The technology once only showed live footage. It soon evolved into a recording system that let users view and save data. This made it the ultimate security technology. Today, property owners everywhere utilize CCTV technology to build simple to comprehensive security camera systems for their safety and peace of mind.

Types of CCTV Systems

Analog – Use Bayonet Neill-Concelman (BNC) connectors on coaxial cables to transmit continuous video signals. They are relatively low resolution but cheap and effective. There are more peripherals in an analog system, e.g., standard coaxial cables do not usually transmit audio. Analog signals can be digitized, making it more cost-effective to go digital even with older equipment. The images require a video capture card and can be stored on a PC or tape recorder. A step up, analog HD enables increased resolution over traditional systems (1080 pixels) and are backwards compatible with analog cameras and BNC.

Network or IP – Used with analog or digital cameras, these systems utilize a video server to stream footage over the internet. The advantages include Wi-Fi and audio support. It also offers Distributed Artificial Intelligence (DAI) for image analysis, remote access, Power over Ethernet (PoE), and higher resolution.

How does CCTV work?

Analog and digital systems work quite differently but modern CCTV networks use conversion software and hardware to convert analog to digital. This process is called retrofitting. A traditional CCTV system comprises of:

• One or more cameras (analog or digital), each with a lens equipped with an image sensor
• A recorder – Either a standard video tape recorder for analog systems, or a Direct Video Recorder (DVR) or Network Video Recorder (NVR) for digital systems
• Cables – Either RJ45 for digital or coaxial for analog
• One or more monitors to which the images are transmitted

A CCTV system works as follows:

1. A camera records images through the lens using image sensors.
2. These images (and often audio too) are transmitted to the recorder or tape, either wirelessly or by cable. Recorders use analytical software and smart technologies to scan data. They send automated alerts to humans or connected systems and devices. This Video Management Software (VMS) records, stores and analyses video feeds. The software is often self-learning, using machine learning (ML) algorithms that utilize functionality like motion detection, face recognition, people counting, etc.
3. Monitor(s) can be passively (through software) or actively (by people) monitored. CCTV networks can, and should, themselves be monitored.

CCTV Applications

Crime Management

CCTV surveillance can deter potential criminals. When a crime does occur, video footage can help law enforcement to investigate and later provide evidence for prosecution in a court of law. Combined with CCTV, audio, thermal, and other sensors can alert officials to unusual events such as fires or gunshots. For businesses, CCTV cameras can detect and monitor in-house criminal activities. Prisons may use video surveillance to prevent drones delivering drugs and other contraband to prisoners. Cameras are able to monitor areas that are not easily accessible, e.g., roof tops.

Disaster Management

CCTV cameras let emergency workers assess and monitor events in real time. They can relay live video to disaster management teams from inside a burning building, a cave, or a helicopter flying over the scene.

City and Community Traffic Monitoring

Law enforcement agencies use security cameras to monitor traffic at intersections and on busy roads. An officer can view the footage anytime. It helps law enforcement identify drivers who run red lights, speed, or drive recklessly. They can then penalize these drivers and focus on preventing more serious crimes elsewhere.

Medical Monitoring and Diagnosis

There are about 43 facial muscles that express people’s thoughts and feelings. Smart software can identify these expressions, e.g., pain or anxiety, from images more easily that people can. CCTV cameras can monitor patients such as children or older people. They help detect medical emergencies like strokes, epileptic seizures, or asthma attacks.

Behavioural Research

CCTV used to research suicide found that 83 percent of people attempting to throw themselves in front of a train showed specific behaviours. These were later analysed from CCTV footage and are now used to alert monitor watchers to potential suicides. Surveillance networks are also used by researchers to record crowd activities in public places and prevent anti-social behaviours. For instance, cameras have been used at schools for security, and to record bullying or playground incidents.

Retail Intelligence

Video surveillance provides market intelligence that helps analyse customer buying trends. It reveals how people shop, which aisles they visit most, and how they respond to calls to action in different store layouts. Heat maps highlight areas with high and low shopper traffic, showing peak buying times and preferred promotions. This data helps stores plan staffing and improve strategies during busy shopping periods.

Analog CCTV vs. Digital (IP) CCTV Systems

Analog Security Cameras

Advantages

• Cost: Analog cameras tend to cost less, sometimes even a lot less, than their digital counterparts on a per camera basis.
• Simplicity: DVR is easier to set up and understand for most. It is one unit with one cost, and the installation is a bit more straightforward.
• Lower Bandwidth Requirements: Analog video files are smaller and use coax cables to send data to the DVR instead of a LAN. This setup uses less bandwidth and puts less strain on your network. DVRs also send data only when someone views the video, not continuously.
• More Design Options: With a wider variety of analog camera designs, you may have an easier time finding a camera model with all of the features you need at a lower cost.

 Disadvantages

• Cabling: The cameras need connections for both power and the DVR, so you deal with a lot of wiring. Even bundled video and power cables don’t reduce it much. Furthermore, coax cables are usually more expensive on their own than the Cat 5 or 6 counterparts used for digital systems.
• Image Quality: The image quality on analog cameras is pretty low. Most smartphones today have higher resolution. As a result, details at a distance may be grainy, making it difficult to identify potential suspects in an incident with a high degree of confidence. Moreover, there’s no digital zoom. If you try to zoom in on something on analog video, you’ll likely get an image that is even more blurred and grainy.
• Coverage Area: Typically, analog surveillance cameras have a much narrower field of view than their digital counterparts, so you may need more of them to cover the area you need.

More disadvantage’s

• Positioning Limitations: Cameras only need a LAN connection to link to your NVR. This setup removes distance limits between the cameras and the recorder. As a result, you become more limited on where you can place your cameras.
• Port Limitations: DVRs have only so many ports on them, so you can only connect a limited number of cameras to them. If you want to exceed this number, you’ll probably have to get a second DVR.
• Wireless Capability (or Lack Thereof): The reality is that analog wireless systems don’t work very well due to government regulations regarding analog frequencies and signal strength. As a result, other wireless devices and even fluorescent lighting can interfere with and distort the video signal.
• Encryption: Analog signals can’t be encrypted, typically speaking, meaning that it could be easier to for unwanted eyes to view the signal.

Digital Security Camera Systems

Advantages

• Image Quality: The image quality from digital security cameras is significantly higher than analog, with many cameras capable of recording and transmitting high-definition video. Plus, digital cameras are more likely to have digital zoom features, which can have zoom distances over 100ft.
• Coverage Area: A single digital camera can cover an area that would require three or even four of its analog counterparts. As a result, you may require fewer cameras and be able to maintain security surveillance over a wider area.
• Fewer Cables Needed: Instead of individually wiring each camera with power and then cabling each camera to the DVR, digital systems can have multiple cameras connected to a switch, and then all of those cameras on the switch can be connected to the NVR with a single cable.
• Positioning or Port Limitations: Because cameras merely need to be connected to your LAN network in order to connect to your NVR, you are no longer limited by the distance between cameras and the video recorder. As the NVR is software-based and does not have ports, you also eliminate that limitation as well.
• Power over Ethernet (PoE): Power over Ethernet switches enable your signal cables to provide power to the cameras as well, reducing the need for those additional cables.
• Wireless Capability: Digital security camera systems are very good at operating within a wireless network. Digital signals avoid analog interference. You can easily view a live feed from remote locations.
• Encryption: A lot of digital security cameras have encryption built in, so your data is safer from the beginning of its journey to its end.

 Disadvantages

• Setup Complications: You may not have the network or switches set up. This can increase your CCTV installation cost and labor. You will still use fewer cables overall.
• Higher Initial Cost: The cameras and equipment usually cost more than analog ones. However, you might need fewer devices, which can balance the overall cost.
• High Bandwidth Requirements: IP security camera systems usually require a lot more bandwidth than analog ones. Between the higher resolution and higher frame rate, even with compression, you’re looking at around 720Kbps, and that’s before considering the newer cameras that have megapixel resolution. As a result, this could drive your costs up.
• Storage Requirements: Higher resolution and higher frame rates mean larger files, so you’ll need a lot more storage space on your hard drive to accommodate them.

Related articles;

Understanding Different Types of Security Cameras

Essential Tips for Choosing an IP Camera Supplier

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