What does the word CCTV mean and where did it come from?
Closed Circuit Television which means that a surveillance camera is connected to a cable (Coax cable) which in turn is connected to a Video Recorder unit (also known as a DVR/NVR/ Multiplexer) or Monitor. The connection between the camera and endpoint device such as a DVR or Monitor via the Coax cable completes a closed Circuit. This is where the closed-circuit (connections) with a Monitor/ Television abbreviates to the commonly known CCTV name.
Today, the term CCTV is globally used as a reference to a surveillance camera or system without highlighting specifically the technology used.
Although IP CCTV is most known to advertise IP surveillance cameras or systems, the term CCTV does not really apply as IP cameras use a Computer Network with CAT5 network cabling to transmit video images. The term CCTV is generally applied in the discussion topic regarding security surveillance.
To start with a CCTV camera today is vastly different than they were 40 or more years ago. Way back in the 1950’s CCTV camera tubes were devices based on the cathode ray tube that were built into CCTV cameras to capture video images. In the early 1960’s the CCD (charge-coupled device) or CHIP was introduced to CCTV, minimising the size of CCTV cameras by at least a 10 fold, with improved image quality and better manufacturing cost. The CCD based CCTV analogue cameras lifespan existed until the early 2000s. In the early 2000s the Industry saw its first IP CCTV cameras.
IP being the abbreviation for Internet Protocol and in everyday conversations, IP can refer to a computer Network or Network/Internet-related product. With the digital age coming into fruition from the late 1990’s and early 2000s, many IP based companies who also manufactured video imaging products saw opportunities to grow their businesses in the CCTV industry, constantly developing and evolving IP cameras (webcams) for the CCTV cameras to what we know them to be today. The IP surveillance technology has proved many advantages over the Analogue technology due to being able to use CAT5 computer cables and share the same transmission path/ Network as IT computer networks use.
Yet, Analogue CCTV has also evolved to ‘HD’ Analogue. In 2009 the Analogue CCTV industry saw the introductions of new ‘Analogue HD technologies called HD-SDI for CCTV which offered HD (1080P) video image based on the Television broadcast standard SMPTE292/M.
In 2012 three further and now dominant Analogue HD technologies called TVI, CVI and AHD were manufactured to offer equivalent “Analogue HD resolutions” (picture quality) to the IP Megapixel cameras available. At that time 720P (1.3MP) and 1080P (2MP) were the norm and equal in resolution to the 1080p or Full HD consumer Televisions sold by high street and online retailers.
CCTV Manufacturers are now often offering both IP CCTV and HD Analogue CCTV to gain both types of customers. Manufacturers also combine all 3 in TVI, CVI, AHD Analogue HD formats to make it simpler for Installers to use different products brands in one CCTV system to ensure that an end-users system can be upgraded with minimal technology restrictions.
While the aim of the blog is to highlight which technologies are best to choose from, CCTV image quality ranks as the most important requirement these days.
With the birth of Mobile phones becoming Camera phones and every 6 to 12 months, new Mega Pixel Mobile phones entering the market, mobile phone companies try to outdo their competitors with offerings of ever-larger Mega Pixel cameras and more camera features.
The CCTV manufacturers development of MegaPixel has been continuous although not at the same pace as Mobile phone cameras.
Starting the first manufactured batches in the early 2000s with 720P and 1080P (2MP) as their first HD promotions in Mega Pixels, since then resolutions have moved to 3MP,4MP,5MP,6MP 8MP (4K) and 12MP as the norm for security surveillance.
Some specialist CCTV camera manufacturers have ventured into the 10, 12, 16, 20 and 30 Mega Pixel cameras with most of them highly specialised to achieve wider field of view coverage, to save on the use of multiple cameras. Other manufacturers with higher MegaPixel cameras have specialised functions either in surveillance or in the other industries such as Machine vision.
With Mega Pixel cameras the higher the Mega Pixels the more quality an image can be achieved. However, not every camera view needs to have higher Megapixels.
If a camera position is required to view a closer scene within 10 metres for example, 1080P (also known as 2MP) would suffice quite happily within this close distance. The narrower the ‘field of view’, meaning the image, the more options the clients have, to choose from camera makes with 1080 / 2MP in the market today.
The wider the image or longer distance covered field of view, such as car park spaces, the more Mega Pixels can be considered to keep resolution in line with a wide field of image.
With Fixed position cameras, these come with 3 types of lenses. Fixed, varifocal or zoom. Most fixed lens cameras should be used in ‘close range’ to keep the high definition. Varifocal is a lens that can be manually zoomed in or out. One could say an ‘all-rounder’ that is useful when wanting to change the angle of view when on site. Mega Pixel Zoom lens cameras offer the best option where distance to view is required. Zoom lenses are electronically controlled, so if the client wishes to see a wider angle or fully zoomed image to its maximum distance, these cameras can be controlled by a joystick or software or App.
With PTZ (pan, tilt and zoom) cameras it has always been our opinion that 2 Mega Pixel cameras are the most versatile in resolution versus cost. When a PTZ camera zooms in, at the maximum zoom the PTZ camera’s image sensor views the zoomed image at 2 Megapixels as it also does when it is fully zoomed out. So whether you have the widest view for general observation of a car park at 2 Megapixel or a fully zoomed image of the entrance gate at 2 Mega Pixel.
Of course, if the client requires ‘more detail’ in the image at maximum zoom, the client then needs to consider higher Megapixel zoom PTZ cameras.
Image quality in terms of Mega Pixels is probably the highest-ranking consideration amongst clients and image quality detail is very important but we also recommend that clients look at the camera’s lighting capabilities.
As with any ‘camera’ today, whether a Digital SLR zoom camera, mobile phone, CCTV, or cameras that feature ‘low light’ capabilities, low light is highly regarded in assisting the camera’s overall image quality.
CCTV manufacturers have drastically improved the ‘low light’ performance and even basic entry-level cameras now come with some ‘night vision’ capabilities.
The top manufacturer’s vast investment into ‘low light’ has benefitted end users greatly, as low light cameras can now see clear CCTV images in near-dark conditions and some ‘low light’ technologies need no ambient lighting at all to give clear coloured night-time images and thereby record coloured images.
‘Some ‘low light’ technologies need no ambient lighting at all to give clear coloured night-time images.’
The low light-coloured images create cleaner and more detailed images, ultimately assisting end-users in reviewing video footage and placing more concentrated efforts on detail in the video evidence.
We would advise any end-user to get a demonstration of ‘low light’ cameras and night-time video recording examples to help their decision-making process as there are many manufacturers, distributors and resellers claiming to sell some models of CCTV cameras with ‘low light’ performance, yet their low light specification and real-life performance are not on par with the market-leading manufacturers.
There are also many different form factor cameras, often referred to as Dome, Turret, Bullet or PTZ cameras.
Dome cameras have a half-sphere clear see-through dome bubble and were an industry-leading form factor. It allowed installers to mount the cameras in all types of environments and move the internal ball-type CCTV camera into any angle. While these have been sold in millions, there have been in 2 inherent issues with Dome cameras.
1- If dome cameras were exposed to rainfall, the rain could often settle on the dome and directly in front of the lens, thereby making the view out of focus and ‘blind’ to some extent.
2 – With a clear bubble Dome, natural sunlight could often be reflected due to the nature of the curved clear dome and the distance to the camera lens. Through time, installers have learned to observe the sun travelling from East to West as well as mounting the Dome camera horizontally to minimise or eradicate the reflection issue.
Turret Cameras were introduced in the last 10 years and are a good alternative to using Dome bubble cameras. Turret cameras still have the manoeuvrability as a Dome bubble camera to achieve the same viewing angles required, but Turret cameras have a flat glass lens which does not suffer from light stream intrusion.
Bullet cameras like Turret cameras have a flat glass lens but their form factor is that of a tube with a bracket on the end. These Bullet cameras were introduced as fixed cameras with zoom lenses but over the years have been made to offer fixed and varifocal lenses as well. With Bullet cameras offering a fixed position and zooming capabilities are often a cheaper alternative to a PTZ camera which is larger in size and mechanical hardware and larger zoom lenses. While bullet cameras are more budget-friendly compared to PTZ cameras, there are distinct advantages and disadvantages to be considered.
Advantage – A bullet camera is a fixed position camera, usually lower cost compared to a PTZ while still being able to zoom long distances.
Disadvantage – A bullet camera being a fixed position camera can only view wide-angle images straight in front of it or fully zoomed directly in front of it, whereas a PTZ is a moveable camera and can change its view when a client requires to change the CCTV view at times, with most PTZ also offering pre-programmed Tours to view as much of the available views possible.
PTZ or Pan Tilt & Zoom camera’s main advantage is that the camera can move to any point in its viewing range and either zoom out, partially or fully zoom in. The PTZ camera’s internal functions allow it to move if an ‘alarm trigger’ from another area/zone is pre-programmed. A PTZ camera can cover vast areas on the premises over and above several fixed cameras.
Coax Cabled CCTV Recorders
Having chosen your Megapixel cameras, whether they are fixed lens, varifocal or zoom lens types, with low light capabilities for night time and which Megapixel quality, the CCTV video images need to be recorded onto a Digital Video recorder to keep the evidence for when video evidence needs to be found and archived for later use.
Since the early 2000s, CCTV recorders have become digital. By that, we mean that a recorder is recording CCTV footage onto a Hard disc drive. The first Digital Video Recorders (DVRs) recorded camera images from Coax cabled cameras and recorded images directly onto their hard drive rather than old-fashioned tape.
Early DVRs were marketed with new Terminologies to promote their capabilities and these were known as Simplex, Duplex or Triplex DVR’s and while these terms are not often used any more, it is worth understanding the terms. There are DVR’s in the market which are simplex or Duplex in operation, more likely at the budget end. So ensure to ask for clarification if your chosen DVR is a Simplex, Duplex or Triplex capable machine.
Simplex DVR’s allowed you to record video but not playback/ watch recorded images or archive video at the same time. Simplex machine recordings had to be stopped to allow an end-user to playback video. Furthermore, you had to write down the time, date and camera number manually to stop playback to use the archiving functions. Simplex was or is simple and therefore an entry-level price CCTV DVR for a reason.
With further development, manufacturers brought out Duplex DVR’s which offered both recording and video playback simultaneously. Duplex machines offered Archiving as a separate function and meant that you could not record or playback while archiving.
The last of the developed entries of DVR’s were the Triplex DVR’s which featured live playback, recording and archiving of Video images all at the same time. Triplex capability can be found in most DVR’s today but these terms are not often referred to any more. For that reason, it is worth checking the specifications or asking the Integrator or supplier which type DVR has been offered.
DVR’s for coax cabled cameras have improved year on year, bringing more features into them and more comprehensive evidence search functions. DVR’s in the market today offer analytical features such as tripwires, zone intrusion, objects left or objects removed, face recognition, power over Coax and Megapixel resolutions to suit the specification of your camera just to name a few.
A tripwire is marked in the DVR’s menu section, with a sample video image of the camera in question. For example, the boundary (perimeter) or entrance, a coloured line denotes the tripwire and will record video on its hard drive as an ‘alarmed’ video footage when that boundary has been crossed over. This tripwire can be manually drawn with a mouse and re-configured to suit the end-users requirement on the perimeter. These tripwires can also have additional functions such as ignoring traffic from the left and recording traffic from the right.
If the client has a zone within that scene that is out of bounds and requires highly important video images to be recorded then the Zone intrusion not only records video footage but also adds alarm output features, enabling security engineers to fit Sounders, visible alarm Beacons etc. This function is very useful where Health and safety on the site requires a Zone to be out of bounds for personnel.
With the advent of Facial recognition development in Access Control Systems and Video analytics, ‘Face recognition’ was also introduced into DVR’s. It is worth noting that most DVR’s to do not recognise a face against a database to confirm the same person. Most DVR’s have algorithms to identify a head & face within the CCTV cameras view and storing that separately as ‘face recognition’.
Objects left or removed are self-explanatory by recording ‘alarmed video’ if an object has been highlighted when an object has been placed into the area or an object being removed. The DVR will take a reference picture in its menu settings and always compare the reference image against the actual scene.
Power over Coax is one of the latest technological advances brought out by manufacturers on their DVR’s. Usually a Camera is powered locally, requiring a mains power outlet to provide power for a camera power supply unit at the camera location. Power over coax provides the camera’s power over the same video cable from the DVR. This feature reduces the installation cost at the various camera locations due do not requiring local power installations. While this technology is relatively new, it is recommended for an end-user to seek Integrators feedback on the suitability of power over coax for their site. Often an Integrator will not use existing old coax as power over coax would not be guaranteed due to the existing coax age or degradation.
Most DVR’s allow for simultaneous recording of different Coax technologies, meaning that existing TVI technology cameras, as well as CVI, AHD and even CVBS (original analogue), can all be connected to the same DVR.
DVRs have always been sold with specific ‘inputs’. Inputs are the physical camera connections into the DVR. 4, 8 and 16-camera input DVRs are the norm and for larger sites, 32 and 64-camera DVRs are also common. We would also recommend splitting the total amount of cameras over several DVRs.
For example, if your site had 128 cameras, we would recommend 4x 32 Camera DVRs. Should the unfortunate happen and a DVR break down, your 3 remaining DVRs are still operational and recording. A DVR with 4, 6 or 8 Hard drives spread over 4x DVRs offers more storage capacity compared to using a 128 input DVR with 10 or max 16 Hard drives. So spreading the risk and performance over several DVRs may seem over the top in hardware installed but offers less risk and more options for archiving.
Almost every DVR sold today has Network capabilities, enabling the video to be exported to other external Hard disc drives, sending live or playback images to mobile phone CCTV Apps, Tablet Apps or web browser/video management software.
Where end-users need to get clarity on, is the DVR’s overall performance capabilities to suit their camera’s performances. If the client has 8MP (4K) CCTV cameras, then the DVR needs to be able to record the same 8MP onto its HDD.
Some DVRs are being advertised as 5MP,6MP and 8MP (4K) recorders but be aware that some DVRs do not make it clear as to how many inputs can record these higher Megapixel cameras at the same time while having lower resolution cameras connected also. While DVRs are advertised as 4K DVRs, it may be that only 2 or 4 out of a total of 8 inputs of a DVR can record 8MP (4K) and may also have slower video speed (frames per second) to record for the 8MP cameras.
Advertising can be misleading, and some 4K (8MP) DVRs allow for the recording of the 8MP (4K) cameras, yet the DVR lets itself down by only outputting 2MP monitor resolutions. These DVR brands could argue that you can zoom into the recorded 8MP (4K)image, but if you have an 8MP camera, why would you not want to see the full 8MP on a full-screen playback?
Checking spec sheets for Megapixel recording and playback capabilities should be one of the important facts to check first and foremost.
At the same time other DVR models with true 4K (8MP) Monitor output, show the complete 8MP camera resolutions in full-screen mode. There are just as many true 8MP (4K) DVRs with 4K Monitor output to give the full
Mega Pixel and max recording resolution.
There are now just as many DVR versions as there are cameras, as the Far Eastern manufacturers can easily manufacture different performance versions for every budget.
Sure, there are many clients for whom the technical specifications, performance differences and limitations can be too much to see through to get a clear decision but there is professional advice at hand.
A reputable Integrator will be able to advise on which Mega Pixel resolutions are suitable for which areas of your premises, where ‘low light’ cameras would be recommended to suit dark areas or camera locations that do not have any ambient lighting in the scene.
The Integrator should also be recommending the correct DVR with the correct Mega Pixel recording and playback capabilities as the client is considering.
Network Video Recorders
The IP CCTV industry has developed from a Virgin territory from the late ’90s and is now a first choice CCTV technology for many upgrades and in most cases for new projects. Like an IT computer network, the interconnected cabling structures of a computer network so IP CCTV flourished due to an existing network technology to transport CCTV video images.
Similar to Coax cameras, IP security cameras have been developed with the same basic features, however, being in a digital age, new uses in IP cameras have been developed. IP ANPR cameras are automatic number plate recognition cameras with built-in algorithms to calculate the shapes of letterings into recognisable number plates that are then transferred into a database for correlation. Facial recognition cameras, where the visual video image of a face is analysed using algorithms and correlated with databases for identification.
Network Video recorders again, operate with similar features as their DVR coax-based counterparts, yet offer more IT functionality and possibilities such as video storage transfer to multiple hard disc locations, if needed.
Network video recorders are the go-to product, where a network exists between buildings, allowing the computer network connectivity to provide the transport between IP CCTV camera and Network video recorder.
PoE-enabled IP cameras can be powered by the Network video recorder (NVR) power supply and is referred to as PoE (Power over Ethernet) for both cameras and NVRs. IP CCTV has long since taken technologies from its IT Industry friends and further developed these IT functions into the IP CCTV world.
As with any IP-based technology, PoE has been developed further in providing ePoE technology that uses advanced modulation to transmit video, data, and power up to 800 up to 10 Mbps on a single CAT5E cable between an IP camera and a PoE switch.
These improvements allow for greater escalation of CCTV IP cameras being deployed on-site, yet being powered by NVRs with ePoE, or CCTV IP ePoE network switches minimising the need for localised power distribution to localised cameras.
The overall benefit of IP Network video recorders over Coax DVRs is that these can communicate anywhere in the world, between and with each other as well as other devices to give greater intelligence to suit their industry and video evidence.
What system? – Coax-based CCTV or IP-based CCTV for my site?
If the client is looking to upgrade an existing CCTV system, then keeping to the same technology most often is the most logical and economical. There are not many benefits in building an IP system on an existing coax-cabled system. Even with today’s market where video transmission equipment varieties can transmit IP camera video over existing Coax cable and vice versa.
The upgrading costs are best applied to the same technologies, to provide valuable additions rather than more expensive integration equipment add-ons to utilise two completely different technologies
Coax-based systems are ideal for small to large camera sites where coax cables can run to 500 metres between cameras and DVR. Even with multiple sites being installed with coax-based systems a client can monitor various site DVRs or cameras from sites via the brand’s dedicated video management software or other 3rd party multi-site software packages.
Where Coax-based cameras are less attractive in applications, is where camera intelligence is required or on-camera feature changes can be controlled.
Coax cable-based Megapixel image quality is just as good as IP video cameras with equivalent resolution.
IP CCTV cameras can range vastly in their technical features, giving greater choice to clients’ operational or functional needs. IP cameras can be accessed anywhere in the world and changes applied remotely, making maintenance/software upgrades easier and more cost-effective.
A few specialised IP camera manufacturers have built their video recorders into the camera, being controlled and monitored via a web browser or management software. This benefits end-users who only need a single camera and have the ‘NVR’ built inside the IP camera.
Again, some of these special surveillance IP CCTV cameras are manufactured with Face recognition or ANPR functionality offering further value with its ‘features’ and onboard recording.
IP cameras and NVRs have a greater Mega Pixel range with manufacturers concentrating on IP-based Mega Pixel growth. IP-based video technologies from broadcasting, machine vision, robotics etc. bring opportunities to the IP CCTV / IP security camera markets, often sharing ‘open’ technologies to improve the future where IoT or the Internet of things are concerned.
Bringing in a CCTV specialised Integrator provides the end-user with greater advice and choices of technologies and a large pool of specialised CCTV equipment options.
Making key decisions is vital for the business or residential homeowner as any CCTV security budget is likely to be spent to either secure, prevent accidents, keep health and safety procedures up to date or provide suitable evidence against theft or provide a deterrent against theft.
Understanding a little more as to what CCTV technologies are out there may well help the client in deciding whether to upgrade or start with a new system and get the best out of their spending budget.
A good Security Integrator will have experience in guiding the right CCTV technology to the client’s needs and the client’s requirements. Additionally, Integrators will be aware of the latest technology features from different brands which would ultimately serve the end-user best.
Related to post: Best CCTV Camera for office CCTV camera types and features IP surveillance camera system Network maintenance services Questions to ask about CCTV Cabling Infrastructure Design Specification for New Buildings CCTV system – technical design CCTV Technology Handbook