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Beyond the Datasheet: Internal VS External IR illumination

February 12th, 2018 by Bethanne Pugh

Which IR illumination method is most suited to your applications

The ability to monitor ’round-the-clock’ is a common requirement for CCTV applications. This can be easily achieved with the implementation of a day/night IP camera and some form of infrared (IR) illumination; which together, enable the continuous delivery of video surveillance – even in complete darkness.

When it comes to infrared illumination, you generally have two choices: internal or external IR. ‘Internal’ being a day/night IP camera that features integrated infrared LEDs, or ‘External’ meaning the use of a separate IR illuminator unit alongside your network camera. To help you decide which method is best suited to your requirements – we have done a quick run through of the pro’s and con’s that are associated with each solution.

Internal IR

green-tick Cost-effective – By purchasing a day/night IP camera with integrated infrared LEDs, your illumination solution is already built into the network camera – meaning there is no need to purchase any additional hardware. This is also a handy time-saver when it comes to set up, as you will only need to install and configure a single unit.

green-tick IR enhancement technologies – Overexposure can be an issue when using infrared illumination and results in poor quality, low-light video. To help combat this and deliver detail-packed footage in the dark, manufacturers have introduced advanced IR technologies into their product ranges – one of these being Axis’ OptimizedIR. This high-performance technology allows Axis IP cameras to intelligently adapt the level of IR illumination to best suit the scene – preventing overexposure and enabling clear identification. In addition, Axis models that feature OptimizedIR, as well as remote zoom are able to automatically adapt the angle of illumination to the zoom level set – ensuring an evenly illuminated scene at all times.

green-tick Straightforward set up and configuration – By receiving power and network connectivity via Power-over-Ethernet, the IP camera is able to provide power through to its built-in LEDs – simplifying installation, as only one power supply is required. In addition, the inclusion of integrated IR LEDs means that you can centrally manage both the IR illumination and viewing features of your IP camera via its web browser interface – making set up and configuration a much more straightforward process.

green-tick No black spots – IP cameras with infrared capability are designed so that their built-in LEDs will deliver an IR spread that ‘should’ match its horizontal/vertical angle of view – straight out-of-the-box. This helps to ensure that there are no black spots, meaning that the entire scene will be sufficiently illuminated when IR is switched on.

red-cross Costly replacement – When compared to an external IR solution, internal IR looks to be the more cost-effective choice between the two. However, in the event of a faulty LED, the entire IP camera would need to be replaced – meaning costs can start to rack up if there are ever any hardware issues.

red-cross Insects – IP cameras that emit infrared light also produce something else: heat. Both of these contribute towards the attraction of insects such as spiders, which will then reside on the lens cover and obstruct the camera’s view. In addition, this can also cause overexposure due to IR rays reflecting off the obstructing object back onto the lens.

Internal IR provides a straightforward and affordable illumination method that is an ideal choice for most small to medium-sized applications. However, larger-scale or mission critical applications that require higher levels of flexibility and reliability – should consider opting for an external IR solution.

External IR

green-tick Flexible choice – By choosing an ‘external’ solution that consists of an IR illuminator unit and a separate day/night IP camera, you have full flexibility when it comes to the placement of hardware – enabling you to completely tailor a solution to meet your specific requirements.

green-tick See the full picture – Unlike with an internal infrared solution, by placing your IR illuminator and network camera in different locations, any insects that are attracted to the illuminator’s infrared light will reside on the illuminator itself and not on the camera’s lens. This reduces the chance of your camera view being obstructed and also helps to reduce the number of false motion detection alarms – a common issue within security surveillance today.

green-tick Versatile illumination – Most IR illuminators on the market today will be supplied with a range of diverging lenses. These lenses are used to spread the infrared light and deliver alternative beam angles and illumination distances. This wide choice gives you the ability to select the best lens to suit your exact lighting requirements – making external IR a very versatile solution (bearing in mind always that the lens with the widest IR spread will have the shortest coverage distance).

green-tick PoE support – The IP industry’s high demand for networked IP devices has resulted in the release of versatile IR illuminators that offer handy features such as support for Power-over-Ethernet. This allows the units to be plugged directly into the network infrastructure and receive power via a standard Ethernet cable. On top of this, manufacturers such as Raytec are introducing smarter network solutions – such as their Vario2 IP PoE models. These smart units are IP addressable and can be fully integrated into an existing IP system, then managed via the handy Vario IP web interface.

red-cross Cost implications – It will often be the case that purchasing a day/night IP camera and infrared illuminator separately will result in a higher total cost than that of a single network camera featuring IR capability. Not to forget that, with the purchase of multiple units, you will also require additional power supplies / switches, cabling and mounting accessories.

red-cross Labour – With multiple units, comes longer time required for installation and configuration – always something to keep in mind when designing your surveillance system.

Kevin Bowyer – Technical Director at NW Security Group

Kevin Bowyer

“An extremely common problem we see in systems is insects causing view obstruction. This can be time-consuming and costly to remedy and vastly increases the amount of maintenance needed on cameras.

In our experience, cameras with built-in infrared illumination are useful indoors and in controlled environments only, and should not be used for general surveillance purposes. To get the best illumination at night – use an external illuminator. Not only will it reduce your maintenance/cleaning burden, but it will usually give you better illumination and more choice, covering more distance with more intensity and better illuminating the subject you are monitoring.”

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