Round-the-clock monitoring is required for most CCTV applications. You can achieve this by installing a day/night IP camera and some form of infrared (IR) lighting to illuminate the scene. This combination enables continuous video surveillance in all lighting conditions, including total darkness.
When it comes to infrared illumination, there are two choices: internal (built-in) IR or external IR.
A day/night IP camera with integrated infrared LEDs has built-in or internal illumination for night vision. Using a separate IR lighting unit alongside your network camera is external infrared illumination.
To help you decide which to use for your application – read this summary of the pros and cons of each.
Internal IR
Cost-effective
By purchasing an IR IP camera, the infrared illumination is built in, so there’s no need for additional hardware. This also saves time as you will only need to install, configure and power a single unit.
Enhanced IR technology
Overexposure can be an issue when using infrared illumination, which can result in poor-quality, low-light video. To help deliver detail-packed footage in the dark, manufacturers have introduced advanced IR technologies into their product ranges.
For example, OptimizedIR technology allows Axis IP cameras to intelligently adapt the level of IR illumination to best suit the scene. This prevents overexposure and enables clear identification. Models with OptimizedIR and remote zoom are able to automatically adapt the angle of illumination to the zoom level set. This ensures an evenly illuminated scene at all times.
Easier to set up and configure
By receiving power and network connectivity via Power-over-Ethernet, the IP camera provides power to its built-in LEDs. This simplifies installation, as only one power supply is required. Having integrated IR LEDs means you can manage IR illumination via the camera’s web browser interface. This can make set-up and configuration a much more straightforward process.
Even illumination
IP cameras should have an IR illumination spread that matches its horizontal/vertical angle of view, out-of-the-box. This, in turn, should ensure the entire scene is sufficiently illuminated when IR is turned on.
Replacement costs
When compared to an external IR solution, internal IR looks to be the more cost-effective choice. However, in the event of a faulty LED, the entire IP camera would need to be replaced. Therefore, costs can start to rack up if there are ever any hardware issues.
Spiders and insects
IP cameras that emit infrared light also produce heat. This can attract insects and spiders, which can then reside on the lens and obstruct the camera’s view. IR rays reflecting off an insect and back onto the lens can also cause overexposed footage.
IR reflections
Built-in IR LEDs may produce glare or reflections when a reflective or bright object enters the scene. This could cause overexposure, making it difficult to identify objects such as number plates or individuals wearing hi-vis clothing. Using a suitable external infrared illuminator alters the angle of illumination and ensures the reflected light does not bounce back to the camera.
External IR
Flexibility
By separating your illuminator and your day/night IP camera, you have full flexibility when it comes to hardware placement. This flexibility enables you to tailor a solution to meet your specific requirements and also to potentially illuminate a wider scene than your camera’s default field of view, such as for an IR-sensitive PTZ camera.
No obstructions
By placing your IR illuminator and network camera apart, insects attracted to infrared light reside away from the lens and IR reflections from them will more rarely occur, reducing the chance of your camera view being obstructed.
This also helps to improve object detection and classification, decreasing the chance of overexposure and potential false alarms.
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.
The wide choice of lenses allows you to select the best lens for your lighting requirements. Keep in mind always that the lens with the widest IR spread will have the shortest coverage distance (inverse square law).
Lens choice makes external IR a very versatile solution.
PoE Support
The demand for networked IP devices has resulted in versatile IR illuminators that offer Power-over-Ethernet. This allows the units to be plugged directly into the network infrastructure and receive power via a standard ethernet cable. Manufacturers such as Raytec have introduced smarter network solutions – such as their Vario2 IP PoE models. Smart units are IP addressable and can be fully integrated into a security system and managed through software.
Cost implications
Buying a day/night IP camera and infrared illuminator separately typically costs more than a camera with IR capability. Also, purchasing multiple units, requires additional power supplies/switches, cabling and mounting accessories.
Longer installation time
With multiple units, comes a longer installation and configuration time. Something to keep in mind when designing your surveillance system. However, the trade-offs are beneficial.
“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. It reduces your maintenance/cleaning burden. An external illuminator usually gives you better light and more choice, covering more distance with more intensity. In short, they’re better at illuminating the subject you are monitoring.” Kevin Bowyer, Technical Director.
Conclusion
The choice between built-in IR and external lighting units comes down to your needs and budget.
To summarise, internal IR provides straightforward, affordable illumination that is an ideal choice for most small to medium-sized applications. Larger-scale or mission-critical applications that require higher levels of flexibility and reliability should instead consider external IR solutions.