My home has recently had a technological upgrade/addition in the form of a new CCTV system being installed. Just as my previous networking experience was shared here, the same treatment births this topical writing.
In this first article I will introduce the basics of the technology which will then conclude with the reasoning behind my product selection. As part of planning out the series, the second article will cover the next intermediary phase of installation design and planning before the final article documents the installation experience itself.
- CCTV #1: Technology Basics (this article)
- CCTV #2: Selection Process
- CCTV #2: Installation Design & Planning
- CCTV #3: Installation Experience
Context & Industry Trend
CCTV stands for closed-circuit television. Whilst the true technology pioneers have been around for several decades, it is fair to say that the context here is all about home security. Commercially, businesses have been reliant on CCTV technologies since the 1980s when video recording first went mainstream in the form of the VHS vs beta format wars. As of early 2017, the time when this article has been written, there is a clear uptake trend for CCTV deployments in home settings. In part, I believe the instability and increasing crime from recent years is a trigger and cause for homeowners desiring to arm themselves and invest in more security.
The consumer/home user audience for CCTV is naturally at the lower end of the market so the technologies made available are low-cost. To help reduce costs for both consumers and the suppliers, bundling up the components is one strategy that manufacturers have pursued. This makes it easy for home-owners to buy everything in one go. Typically, the product range at this end of the spectrum leverages wireless connectivity for the cameras, since they are generally cheaper and easier to install. The only implication with the wireless type of camera end-point is that each camera needs a power source, which can complicate installations where an electrician may be required to add power-points to the various locations where cameras are to be mounted.
Camera Protection Rating
Whilst CCTV cameras can be used in both indoor and outdoor environments, the more basic models tend to cater for indoor environments, where the quality of their finish lacks the IP67 standard for weather-proofing and basic water-resistance. IP67 is a code within a wider system known as International Protection marking. The rating/code always comprises two numbers. The first number represents the degree of protection provided against the entry of foreign solid objects, such as fingers or dust. These protection levels range from 0 to 6, as sourced from Wikipedia:
- 0: No protection against contact and ingress of objects
- 1: Effective against foreign solid objects under 50 mm. Any large surface of the body, such as the back of a hand, but no protection against deliberate contact with a body part
- 2: Effective against foreign solid objects under 12.5 mm. Fingers or similar objects
- 3: Effective against foreign solid objects under 2.5 mm. Tools, thick wires, etc.
- 4: Effective against foreign solid objects under 1 mm. Most wires, slender screws, large ants etc.
- 5: Effective against dust. Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment.
- 6: Dust tight. No ingress of dust; complete protection against contact (dust tight). A vacuum must be applied. Test duration of up to 8 hours based on air flow.
The second digit indicates the level of protection that the enclosure provides against harmful ingress of water:
- 0: No protection
- 1: Protected against dripping water
- 2: Protected against dripping water when tilted at 15 degrees
- 3: Protected against spraying water
- 4: Protected against splashing water
- 5: Protected against water projected by a nozzle (6.3mm) (equivalent of our layman understanding: water resistant)
- 6: Protected against water projected by powerful jets (12.5mm nozzles)
- 7: Protected against water immersion, up to 1m depth (equivalent of water proof)
- 8: Protected against water immersion beyond 1m depth
In this way, IP67 technically means the product is effectively dust tight with a vacuum seal and able to withstand water immersion of up to 1m depth. The cheaper alternate commonly found is IP54 which offers limited protection against dust and water splashing. I think one simplified way to understand this product attribute is that IP54 products are highly suitable for indoor use whereas IP67 products are better adapted to outdoor conditions, particularly if they are subjected to rainy conditions.
Wired vs Wireless
Wireless cameras are obviously the easiest and most flexible in terms of installing, and thus can be placed in more positions compared to a fixed wired camera. However, for a wireless camera to provide continuous monitoring, a source of power needs to be provided for each camera. This implication can constrain placement and positioning, or require an electrician to add new power-points around a house. Inversely, a wired camera, whilst requiring careful planning for its positioning, has the ability for its power-source to originate from the central recorder/system.
Whilst both wireless and wired solutions are secure, wireless devices are inherently susceptible to signal interference and blocking (in the worse case). Wired solutions can also have their signalling impaired, but the fact that the video and power signalling traverses a dedicated wire, means that a much more visible event has to be triggered in order for impairment of the signal to be experienced – i.e. physically cutting the wired connection, which invariably means someone has physically accessed the wiring and cut it.
There is greater flexibility and scalability with an Ethernet wired solution; assuming the central Network Video Recorder (NVR) has the capacity. In the older analog system, which invariably utilised a BNC cable standard, each camera end-point must be connected to the central Digital Video Recorder (DVR), which is basically the BNC version of an NVR. In contrast, large scale CCTV systems with IP-based PoE cameras can leverage PoE switches that help simplify the physical cabling. In these situations, typically relevant for businesses more so that home environments, where cameras are located in the one close geographic area, a single PoE switch can be used to minimise and reduce cabling. This is important in larger scale projects where the cost of labour and installation time can become the largest cost factor.
Analog versus Digital (IP PoE)
In basic terms, the world of cameras are split between digital and analog. Whilst digital is the long-term future, analog remains cheaper and currently more prevalent. Digital signals are typically IP-based, and the signal can be thought of just another form of data which traverses the same network cabling like any other modern generation of computing devices.
This consideration also is the key difference in explaining analog signalling makes use of a DVR, whereas digital signalling has an NVR. As the terms suggest, both are video recorders and their functions are identical except for the physical connectivity at the rear of each device: analog has BNC ports whereas digital NVRs have the more familiar Ethernet ports.
From a technical standpoint, the two recorders differ in where the video footage is actually processed. In an analog set-up, a DVR is responsible for this, while in an IP set-up this is done in-camera and then streamed to the NVR. In actuality, an NVR is more or less a software program, and while it is usually run on a dedicated, standalone device, there are pure software NVR options available.
NVRs are typically designed to cater for both home, small business and enterprise markets. At the top end of the market, the NVR is rack-mountable and fits into a corporate communication set-up.
System Throughput (Footage Quality)
When selecting a video recorder (DVR or NVR), pay attention to the throughput attribute. Throughput is the standard for determining system performance, as measured in megabits per second (Mbps). The higher the throughout, the more bandwidth a video recorder is capable of handling. At the source end, each camera will send through data which is calculated to consume bandwidth according to:
1. Resolution: The term resolution is more widely understood in today’s modern world given the amount of education that televisions have introduced. The higher the resolution, the clearer a picture is because more pixels, or image dots, are defined for the viewing space. Standard resolutions applicable to CCTV camera systems are:
- Full HD / 1080p: 1080 x 1920
- HD / 720p: 1280 x 720
- 960H: 960 x 480
- D1: 704 x 480
- CIF: 352 x 240
2. Frame rate: The number of frames of images sent by the camera. At its core, video is a whole lot of frrames of images shown sequentially. The higher frame rates, the more frames the video is displaying every second. Thus, higher frame rates provide a smoother image, which becomes more noticeable in action movies. The following Youtube clip gives you a real-life experience of the various frame rates compared and the effect on image/video quality:
Other Camera Attributes
- Night-time visibility: this is measured by the infrared capability of a camera. The current standard technology for enabling night-time vision, is the use of infra-red LEDs.
- Illumination: The use of the measure for degrees of illumination is common to most cameras and we see the metric of lux. The lower the lux value, the better the the camera can detect images and movement in the dark. For a camera that operates in total darkness, look for 0 lux with built-in IR illuminators.
There are four general categories of CCTV cameras:
- Box cameras: This camera is ideal for scenarios where you have a small, specific focal point. The camera is unidirectional and in ther most basic of models, without a lens.
- Bullet cameras: A bullet camera can be adjusted to point at a specific focal point. They improve on box cameras by having a better viewing range/angle, and zoom capabilities. The biggest drawback is that they are visually indiscreet and can stand out. A bullet camera, like a box camera makes it fairly obvious where it is pointing, unlike a dome camera.
- Dome cameras: The featured dome offers a natural protection for the camera lens and makes it less obvious where the camera is facing. Where the capability is built-in, manual adjustment of angles may be possible.
- Point-tilt-zoom (PTZ) cameras: These are the top-end of cameras in that have remote-controlled movement, allowing the camera to follow and track movement. Naturally, these cameras are expensive and their total casing requires them to be physically installed in raised locations, safe from tampering or vandalism.
Positioning of each CCTV camera is a critical consideration for the overall solution. In order to determine the best positioning, the system should be connected up in a basic fashion so that each screen/camera zone can be seen for real. Nothing beats the reality of seeing first-hand what the camera footage/viewing experience will be. With the system bundle that I purchased, we considered briefly whether the base four cameras would suffice. Whilst we had an approximate idea of the areas we wanted monitoring, our theories were adjusted the moment we started working out exact positioning, which was only achieved when we powered up and tested the cameras. More commentary on this will be shared in the installation article.
- I have a strong personal preference for Power-over-Ethernet (PoE) as a cabling standard/option. As the term suggests, the electrical powering of each camera end-point is centrally controlled. The standard of Ethernet cabling means the data signal sent from each camera is IP based. IP standards for Internet Protocol. The versatility of IP technology and relative compatibility with a whole raft of IP-based solutions gives this form of technology a greater opportunity for reuse.
- My previous personal experience with home networking and cabling of Cat 6 cables gave me great insight into the complexity of running wires throughout my own home. To me, adding more cables into the house was worth the effort.
- Choosing a system which allows for expansion makes sense. You cannot really know for sure, beforehand, how many cameras is enough. Some systems combine to provide a combination of wired and wireless cameras.
Given all of these factors, the scene is set for CCTV #2: Selection Process