In our previous article we showed why Hikvision and Dahua are the brands that you want to focus on when choosing the best CCTV camera for your home.
But choosing an actual camera from their various models, is just as daunting a task, given the wide variety of features and technical considerations. In this article we outline, everything you need to consider in making your choice.
In industrial applications we talk about “Operational Requirements” as a first step in selecting a CCTV camera for an application. I feel that that the OR approach, will also serve residential customers well.
The best CCTV camera for your home is going to be the camera that is able to achieve your operational requirement the best.
Once you have defined your operational requirement, it is possible to determine a technical specification from this requirement. Basically a technical requirement will define the specifications of a camera that will meet your requirements.
What after all is the point of buying a camera, because it’s cheap – if it doesn’t actually do what you want it to do. The lowest priced CCTV camera in south Africa, also won’t necessarily be capable of meeting the operational requirement.
Matching technical specifications to an operational requirement, demands a comprehensive understanding of the technical performance features of a CCTV camera. Not everyone who claims to know how to install, or who offers a CCTV camera for sale – has this detail of technical knowledge about the camera. I am confident that once you have been through this article, you will have enough information to be able to make this choice yourself.
An article that attempts to answer this question would give a short answer of “it depends on the operational requirement and the environmental conditions under which the camera will operate” But that’s not likely an answer that would be very helpful – so we have to present a longer form, of more detail to address the issue.
THE FIRST STEP
Deciding what you want to achieve.
The first step in this process is to state the problem that you wish the CCTV Camera to address. It should be immediately noticed that a CCTV Camera on it’s own, cannot solve a problem. It solves the problem as a component of a CCTV or surveillance system. – but let’s try to pursue this in simplistic terms.
e.g 1. I want to detect an intruder (who/what) climbing over the perimeter wall (what/where) during the day and in the night (when) to commit crime on the premises.
e.g 2. I want to be able to see who it is that has stopped at my driveway gate.(what/where) at any time of the day (when)
The next question is then. Who is affected by this requirement. Am I the only person who wants to see the person at the gate? Do other people need to see the visitor?
We need to define a success factor. If the camera does record an intruder climbing over the wall, but he still gets away with the R20,000 of household goods – that is not success.
On the other hand , if the camera detects the intruder, sends us a notification, and we respond by chasing off the intruder before he can steal anything – then that would be success.
So we rephrase our operational requirement slightly.
e.g 1. I want to detect and get early warning of an intruder (who/what) climbing over the perimeter wall (what/where) during the day and in the night (when) to commit crime on the premises, (why) so that I can activate my armed response company, or chase off the intruder before he steals my household property.
How can the problem be solved?
Perhaps there are other solutions that might work better than CCTV. Maybe CCTV cannot even solve the problem.
If you determine that a CCTV camera will be an effective solution to the problem, you need to move on to evaluating the environment, and the technical features required from the camera. Then you will be able to find the best camera for the objective, at a reasonable price based on your risk assessment.
NEXT STEP
Determining technical specifications – what must the CCTV camera be able to do?
DORI – what level of detail must the camera capture?
The first technical determination is derived from what we in the CCTV Industry know as DORI.
DORI is basically a measure for the size of a target object on a display screen, that is sufficiently large to achieve the required objective. DORI is dependant upon the size of your camera lens and the distance or angle of view that is to be observed by the camera.
We categorise DORI as follows;
Detection – which provides enough detail to ascertain with a high degree of certainty, that a person is present in the image.
Observation (Monitor and Control) At this level, we should be able to monitor the number of people detected, the direction and the speed of their movement.
Recognition – The observer can say with a high degree of certainty that the detected target is someone they have seen before.
Identification – The captured image will be good enough to establish the identify of any person beyond a reasonable doubt.
Note, that not all cameras are able to achieve all the DORI levels of performance. Some cameras can monitor wide areas, only for detection or Observation. These wide area views may not provide enough detail for Recognition or Identification of a target. Other cameras may monitor smaller areas in a telephoto view, in order to provide higher detail for recognition or identification.
Less cameras may be required to detect or observe an area, than will be required for recognition or identification of the target in an area.
Your best CCTV camera will need to have a DORI distance capability that matches your desired objective at the distance and angle of view from the scene.
How will the camera display the scene – so you can watch it?
Now, it’s all very well to have the camera observing the scene, but how will you or the assigned person actually view the camera image? Live or by viewing recorded footage?
Do you want to detect the intruder during any time of the day? Just during the night? Or would you prefer to come back and replay the footage to see what happened earlier on?
Where and on what device must you be able to see the image? A cellphone? A display monitor in the kitchen?
Who will be available to watch the display device or view the cellphone footage? Do you have the time to watch replays of hours and hours of video footage?
What will be that person’s response, when they detect the event that is being planned for?
If there isn’t going to be any-one to monitor the display most of the time, then you might not need a display monitor at all. It’s not going to be effective if you only view the display now and again. Believe me – very few of us have the time to come back home and replay 8 hours of video for each camera we have on site. In this case, smart phone notifications and viewing may be all that you need.
Keep in mind that viewing a lot of cameras on a cell phone screen, will mean that each image will be very small. Cell phone viewing is most effective for receiving notifications and viewing one camera at a time. If you want to view multiple cameras, simultaneously, you will need a bigger display screen in a location where you can monitor it.
Responding to the CCTV footage- how will the camera alert you?
By considering these questions you then determine whether the CCTV camera must be able to give visual alerts or notifications when it detects the event.
What display screens will be used – cell phone, tablet, computer or monitor?
How many monitors will be required? And what size must they be?
Must the camera be able to record the footage, and for how long must the footage be retained?
How will you extract the footage if needed and how will you securely distribute it?
What form should the alerts take?
A simple audible beep on the site, activation of a siren or flashing light, a text message, Push notification and image to a key-holder, a relay sent to an armed response CCTV monitoring centre, a recording of the event, or display the event on a monitor or TV?
Do you need a record of the event to be logged?
It is important that you pre-plan your response to receiving a notification from the CCTV camera? What action will you take?
How CCTV cameras detect events – Is the detection accurate and reliable?
CCTV cameras use different methods to detect an event. Some cameras use simple pixel changes to detect motion. These cannot really distinguish between sources of motion, and they may constantly alert for insignificant reasons, such as shadows, changes in light, leaves blowing in the wind, dogs or cats. These are often termed as false positives. A camera with a high rate of false positives has limited effect in crime prevention scenario’s.
Yet other cameras employ artificial intelligence. Using algorithms these systems are able to determine with a higher level of certainty whether a human, vehicle or some other object has caused the motion. This type of camera produces more reliable notifications and event alerts.
What maintenance and repairs will the camera require?
What about the maintenance requirements for the camera? How and when must it be cleaned? Can it be upgraded? What warranty is required on the camera, and how long must the camera remain relevant before it is viewed as obsolete or outdated equipment.
Let’s consider some issues related to the vendor of the camera. If the camera requires repairs or warranty replacement, what is the turnaround time for dismantling the camera, sending it for testing, having it repaired or replaced? Who will handle this task, and will a replacement unit be available while the camera is off-site?
What Frame Rate should the camera be capable of recording?
Now we want to look at how fast the target that we want to observe, will be moving.
Usually in a residential setting we are concerned with slow to medium moving targets, and the scene activity is not usually very busy. This allows us to specify lower frame rate cameras, so we don’t need a camera or system that must record a fast moving target or very busy scene at high frame rates per second.
Usually 7fps to 15fps will be adequate for a residential surveillance system. Real Time recording at 25 or 30fps usually just represents an unnecessary expenditure in a residential system. Most entry level CCTV cameras will be suitable for this frame rate.
How will the camera store or record the video – and how long will it retain it for?
Another consideration of the camera is how long it must retain the stored video for? How long after an event will it be determined that footage of the event might be required?
Do you need to watch the replay of a single camera, or do you need a synchronised replay of multiple cameras?
For short retention periods, and single camera playback – some cameras are fitted with on-board SD cards for storage. The SD cards can be limited to 128GB or 256GB and at low frame rates and low quality might be abe to record continous high resolution video for 7 days at a time.
If you need longer retention periods, and synchronous replay of cameras, it might be better to connect the camera to a recorder which accommodates large capacity hard drives.
Generally residential users will need shorter retention periods, and single camera playback should suffice. However if AI cameras are being used, or continuous recording is selected rather than just recording motion – additional metadata needs to be recorded alongside the video.
Generally we recommend continuous recording for security systems in preference over motion detection recording only. MD only recording can result in missed footage.
Most CCTV cameras offer easy extraction of the recorded data by downloading it over a network, transferring it to a USB drive, or simply reading the SD card in a SD card reader.
Extracting video in a residential setting rarely requires specialised technology to watermark, or protect images against tampering.
Can the CCTV Camera see in the dark?
You are rarely going to have well lit areas all over the yard. The camera needs to have some ability to see in the dark at the distance to the target scene, or you have to provision additional lighting to aid the camera in seeing at night.
Infra-Red
Many cameras are equipped with infra-red lamps that produce a spectrum of light that enables the camera to see in the dark. Infra-Red cameras will display black and white images at night. These images can be very crisp and clear with a good quality camera.
Infra-Red cameras will be rated in terms of meters for IR vision. Generally these cameras start at a 20 meter night vision range.
Consider that many of these cameras aren’t capable of the rated ranges in wide open areas, outdoors. These cameras often require surfaces to absorb and reflect the light. In a wide open area with no trees and objects, a 20m camera may actually only see about 8m at night. Generally we try to get a camera rated at double the IR range that we need to the specific target – outdoors.
Full Colour
The trend these days is to get white light cameras. These cameras activate lamps at night that act just like a spot-light. These full colour cameras provide colour images at night.
These cameras tend to work well in narrow scenes and short distances. In wide scenes and longer areas the fringes of the image will tend to be dark, and will conceal the detail on the fringes of the image.
Full colour cameras may also annoy occupants if they are installed in-doors and don’t have the function to disable the white light, in favour of IR.
Contrasting Light Levels.
Another issue that a CCTV Camera must deal with is contrasting light levels in a scene. For scene’s of high and low light level contrasts, the camera must be equipped with features that can compensate for the poor image that might result. When cameras are facing strong sunlight, observing an entrance or opening that is very bright compared to the interior, looking out of a window, or down a dark corridor with a window at the end – the image will be overexposed, silhouette, or dark.
Cameras feature Wide Dynamic Range (WDR) Back-light Compensation (BLC) and other to deal with this.
Viewing Number Plates.
Another instance where camera performance may disappoint, is when you expect to be able to see number plate characters.
Most cameras will not be effective at discerning these characters, unless you have matched the camera DORI to this objective – and then only in the day, or when you have a full colour night camera that isn’t reflecting light off the number plate.
An Infra-Red camera will normally overexpose the number plate at night.
If the vehicles headlights are on, the camera will be blinded and unable to see the number plate.
Recording number plate information requires a dedicated, and very expensive camera to achieve that requirement.
What size lens does the camera need to meet the DORI objective?
Cameras are equipped with lenses of different sizes. The Field Of View (FOV) or angle of view is dependant upon the lens size.
Very small lens measurements like 1.4mm or 2.8mm will provide a wide area of coverage, while larger lens sizes such as 12.5mm and 30mm will provide telephoto or tunnel vision angles of coverage.
Wide angles of coverage will not render high resolution detail in the scene at anything more than a few meters in front of the camera, while telephoto coverage will deliver higher resolution detail, at longer ranges from the camera.
When choosing the best CCTV camera for your home, you need to measure out the area that you plan to cover and the level of detail required at the target. Now you can measure the angle required to cover the scene and match a camera with a relative lens size to the scene.
For detail at longer distances, you will usually have larger lenses and will need more cameras to cover an equivalent area – while achieving the desired DORI objective.
Unfortunately, when home owners shop online they tend to purchase a set of cameras all with the same 2.8mm lens size. This is also common when poorly qualified people are engaged to install a CCTV system. Often this specification does not suit all the scenes to be covered at the home. Camera FOV must be matched to each scene required to be covered.
Is a fixed view camera or one that pans and tilts best?
In residential applications usually fixed view cameras are best. Pan, Tilt and Zoom (PT Z) cameras are active surveillance cameras.
PTZ cameras are effective when there is a dedicated operator manning the camera – it has a low probability of detecting an event if there is no operator behind it.
Bullet, Dome, Turret or PTZ – Which type of camera is best?
Bullet cameras are usually employed outdoors and are intended for longer range video. Dome cameras are usually deployed indoors and intended for shorter distances but wider angled scenes. Bullet cameras are now available with 1.4mm and 2.8mm FOV providing short range, wider angled video outdoors. These are suitable in a limited number of cases.
Turret Cameras are basically dome cameras. The turret camera is generally more flexible in being able to pivot in any direction inside it’s socket mount. Standard dome cameras are not as flexible in the direction of view.
Dome cameras also come in heavy metal versions, and may be marketed as vandal proof.
What resolution is best for a home CCTV camera.
We can use the example of home television to demonstrate this point. In the early days of High Definition television, households would buy HD ready television sets, these usually produced 720p or around 1 megapixel of resolution, then we upgraded to 1080p or Full HD television sets producing around 2 Megapixel. Currently it is the current standard to have 4K television sets. A 4K UHD television set produces images of 8.3 Megapixels.
What is the motivation for continually upgrading the television standard?
Simply – the higher the resolution of the television set, the more detail it is able to display. Your movies and TV shows will look better.
The price of a CCTV camera is heavily dependant on the resolution it is able to display.
720P cameras are relatively inexpensive and you can get them for around R200, while 8MP CCTV cameras are generally not within the average home budget. Like the television standard, 4K and 5 Megapixel resolution cameras have become the standard.
The best resolution for your camera is matched to your surveillance objective.
If you simply want to detect or monitor an area, you might not need a high resolution camera. Although a higher resolution camera can have a wider FOV than a lower resolution camera. You may need more low resolution cameras to cover the same area that a single High Resolution camera may be able to cover.
If the detail in the scene is important for recognition or identification, or deciphering characters or lines, then higher resolution cameras are required. This can also be achieved by using lower resolution cameras, but will only be effective at very short ranges.
Wired, Wireless, Analogue or IP Cameras – which is the best?
In this section we are concerned with how the camera will transmit it’s video image for viewing, and how the camera will receive power to operate.
HD Analogue Camera.
Analogue Cameras generally will rely on a cable with connectors to send analogue video signals to the monitor, and will also receive power along a copper conductor pair of wires.
The cable is readily available and usually the video and power transmission cable is all contained with a fused twin cable.
Most Analogue Cameras are currently HD capable and will be seen on the market as HDCVI, HDTVI, or AHD camera notations.
Generally HD Analogue cameras must be coupled to a recorder, or a monitor for the video to be viewed. The recorders represent additional costs, and their function is usually limited by the low powered processors and GPU’s used in their construction.
These type of cameras also require additional external power supplies to power them.
Wireless Camera
Wireless Cameras are not always actually free of wire. The wireless simply refers to the transmission of the video through the air using digital signals, gsm, Bluetooth or other radio communication. Most of these cameras still need cable to provide them with power.
Wireless Cameras with Lithium Batteries are now emerging. In some cases a single battery charge could last for 6 months.
Another recent trend is the provision of small solar panels for connection to these cameras. The camera can be powered by solar power or the solar panel keeps the built in battery fully charged.
There is currently a proliferation of cheap gimmicky cameras of this type on the market.
Wireless cameras are very dependant on strong signal coverage at the place of installation.
Home WiFi usually requires WiFi extenders and repeaters to provide strong signals to these cameras. Loss of connectivity is common with these cameras when signal strength is low.
Wireless Cameras , like IP cameras do not need to be connected back to a recorder for viewing. The data is transmitted via the Wireless Network and can be viewed on cell phones or computers with the relevant software app.
The video can be recorded directly to the viewing device, or to a built-in SD card contained on the camera.
There is another emerging type of wireless camera, which is the lighbulb camera.
These cameras can replace your home lighting by screwing directly into the light socket, or with a socket adaptor. The cameras get power directly through the light socket.
Once again there are currently a number of these cameras on the market, supplied by small manufacturers, and many of them are just gimmicks.
We do see a lot of potential for such cameras, especially when coupled with solar power – to simplify the cable labour required in CCTV installations.
IP Camera
IP cameras can best be viewed as stand alone mini-computers. Each camera is wired back to the local network, and can receive power from a suitable network port. Most residential homes won’t have this type of network switch available though. Power over Ethernet switches would need to be provided at the home, or additional external power supplies will be required to power the camera.
The advantage of an IP camera, like wireless cameras, is that it does not need to be connected to a recorder. The number of IP cameras that can be deployed is therefore not limited by the number of connectors available on a recorder. Video storage is usually achieved with a Storage media attached to the network or solid state memory cards or drives built into the camera.
Video can be viewed over the network on smart devices or computers.
Another advantage of an IP camera is that it only has to handle digital processing and computing activity for a single video stream. It is equipped with a CPU and GPU, and other chips that are powerful enough to handle that amount of processing.
These cameras are able to handle more advanced Artificial Intelligence algorithms and compute processes, to produce better quality images and more accurate and complex event detection notifications.
The HD Analogue camera system is constrained by the processing power of the recorder, which has to handle multiple video streams.
Although the IP camera does not require to be connected to a recorder, virtually every installation of IP cameras that I have seen, employs a Network Video Recorder as well. There is only one reason for this. It is not desirable to have your video surveillance and general network data on the same network. A single network will suffer from performance issues and creates an insecure network.
Network Video Recorder.
The Network Video Recorder is intended to create a separate network for your security system.
It also creates a network that would not be available in a standard home. Additional network switches, Power over Ethernet switches, Managed Switches and network attached storage devices are common in corporate and industrial sites – but not in the average home. The NVR is such a network in a box.
Virtually every IP camera installation, that I have seen in homes is deployed poorly.
The very purpose of providing a recorder is to create a separate network. The installers though will directly connect the NVR, or PoE switches to the unmanaged home broadband router. No network segmentation and there is then no benefit obtained from the IP camera system. Incidentally IP camera systems cost about 60% more than HD Analogue systems, and deployed in this way might just represent fruitless expenditure.
How much storage will the camera need?
HD Analogue Recorders and IP cameras employ video compression methods to reduce the amount of storage space required to store the video.
Hard Drive storage is quite expensive – so the type of compression supported by the system is important.
Current standards are H.265+.
Older methods like Mpeg, M jpeg or H.264 amongst others, will require increased expenditure for adequate hard drive space.
What is the price of CCTV – are you paying too much or too little?
Risk assessment is the most reliable method to determine what is a reasonable price to pay for your CCTV camera.
Using our objective above, we do a simple risk assessment.
How often do intruders climb over our wall, walls in the neighbourhood, walls in our city?
What do they do when the climb over the walls? What is the likely consequence of those actions?
What losses can we experience if they climb over the wall.
Now all we need to do is multiply the number of times for such an event over a fixed period – say five years, by the monetary loss that we might experience each time they do this.
e.g. We have had information of 5 perimeter intrusions in our neighbourhood over the past five years, in each case the victims lost about R20,000. So 5 x R20,000 is R100,000 – this is the monetary risk involved in the problem.
This monetary risk value helps us to establish a reasonable cost for the CCTV camera or system, once we have assessed the total risk for each of the problems we are trying to solve..
- Generally we can use a value of R3 million rand for loss of a life, if that is a credible risk.
In this article we have aimed to assist you in selecting the best CCTV camera for your home, and provided a very simplistic approach to determining what type of camera you need.
There is a perception that cctv cameras can be bought from online vendors, who have no experience with the actual installation of cctv cameras – at a cheaper cctv price.
We invite you to check out our online cctv purchasing system here : Gentech Ecommerce – Tech For Life
Alternatively, book a consultation with Gensix Technology: Book A Consultation – Gensix Technology
