Comparing Surveillance IR IlluminatorsBy John Honovich, Published Feb 27, 2011, 12:00am EST
Video quality at night can be very poor. Even cameras that rate their minimum illumination as .1 lux or less routinely display dark, noisy images at night. One of the most direct ways to rectify this problem is to add IR illuminators to provide artificial 'invisible' light.
In this report we examine add on IR illuminators to better understand the differences and trade-offs among the options available. We have concentrated our comparison and review on 3 commonly cited product offerings:
In the last year, a surge in IP camera manufacturers offering integrated IR illuminators - from Axis's dome IR accessory to Bosch's IR SMB series as well as Sony and Arecont's new megapixel series with integrated IR. Of course, these manufacturers are not alone. Many, if not most, Asian manufacturers have offered such products for years. The recent trend is primarily the rest of the world joining in.
In this report, we focus on the other side - the manufacturers who develop add on IR illuminators. We look at the distances achievable, power requirements, premium features, cost concerns and more.
This is part of our ongoing series of reports on low light surveillance. Here are other relevant reports and tests we have done in this area:
- How Exposure Impact Low Light Performance - 'regular' cameras can look great in extreme low light conditions if you use this common manufacturer trick but the downsides are severe
- IR Illuminator Performance Tested - examines image quality, issues with overexposure and limitations in IR bandwidth savings (contrary to vendor claims)
- Megapixel Camera with Integrated IR Tested - demonstrates the good and bad of using a camera with integrated IR
- Thermal Camera Tested (Axis) - shows the strengths and weaknesses of thermal as an alternative to using IR
- EMCCD (Super Low Light) Camera Reviewed - examines the potential of super low light color video from a specialized EMCCD camera
- Majority of IR illuminators are low-voltage
- Low-Voltage IR illumination reaches roughly 300 meters in today's market
- High-Voltage IR illuminators can deliver up to roughly 1000m
- PoE illuminators are now widely available and with stated distances up to 95 meters
- PoE illuminators are generally 'dumb' having no logical presence or controllability the network
- Bosch, Iluminar and Raytec likely source 'raw' LEDs from the same supplier
- All IR illuminators surveyed are well equipped for outdoor use with IP66 or better ratings
- Photocell sensitivity and LED power adjustments are standard features
- Telemetry control of IR on/off and D/N camera switching output present on majority of models (notably absent in Bosch's shorter ranging EX12LED series)
- Almost all models offer a 850m and 940nm covert option (850nm generally being the 'default' wavelength)
- Raytec offers the broadest product portfolio and largest number of features
- Raytec: RM25-F-50 [link no longer available] (list $369 online $330) 14 meters (50 deg)
- Iluminar: IR148-A60-24 (list $400) 19 meters (60 deg)
- Bosch: EX12LED-3BD-8W [link no longer available] (list $418 online $250) 15 meters (60 deg)
- Bosch: SLED10-8BD [link no longer available] - 320m/10 degree (List $2,744 online $1500)
- Raytec: RM200-F-AI-10 [link no longer available] - 300m/10 degree (List $2,004)
- Iluminar: IR919-A10-24 - 280m/10 degree (List $1,650)
- Output Power - Maximum IR light that can be generated by an LED (ranges from as low as 30mW to almost as high as 1000mW (or 1 W)
- Efficiency - how much of applied power is turned into IR light versus heat
- Control illuminator power using camera/VMS analytics (e.g., based on subject's location in near or far field)
- Control power and photocell sensitivity over a network or centrally
- Monitor performance and health of illuminators
- PoE standards for greater power (25.5W to PD)
- Higher LED efficiency
The surveyed manufacturers' IR illuminators are fundamentally similar in technology and pricing. Only modest differences exist among elements such as illumination distances and beam angles, LED source used, outdoor ratings, and pricing. As such, finding good price/performance in an IR illuminator for a given application warrants a low level examination into the technical distinctions across manufacturers and their models.
Below is a summary of notable survey findings:
If an application calls for IR illumination ranges beyond 300 to 400 meters, only high voltage options are available. Raytec is the only manufacturer offering add-on illuminators at these ranges while Bosch offers a 1200m integrated camera / IR illuminator system.
For short-range or narrow applications (e.g., <15m) built-in IR is going to be significantly cheaper than even the least expensive add-on IR illuminator from any of these 3 manufacturers. Pricing for the shortest ranging add-on IR illuminators from each manufacturer surveyed falls in around $400 (list) and offer distances averaging ~17 meters:
Based on online pricing, products costs will likely be around $250 to $330 for adding on an IR illuminator. Furthermore, additional installation/labor costs are necessary for an add on IR illuminator. By contrast, the premium for an IP camera with integrated IR illumination is generally not more than $100 or $150 over a 'regular' camera (see our list of ~60 IP cameras with integrated IR illuminators).
Despite the few hundred dollar cost premium, reasons to select an add on IR illuminator include (1) choosing a specific angle of illumination (almost always fixed for integrated IR, (2) placing the illuminator away from the camera (not possible with integrated IR illuminators), (3) concerns about image quality issues and (4) concerns about IR durability / reliability. As we examine in the IR LEDs section, all 3 of the add on IR illuminator manufacturers use high end LEDs. Cameras with integrated IR illuminators generally use lower quality IR LEDs (though determining which ones specifically is difficult).
For longer range or wider area applications, add on IR illuminators are necessary (presuming you do not elect for much more expensive thermal or EMCCD options). Of the long range IR illuminators, the lowest cost options are offered by Iluminar. Bosch MSRP is the highest but they appear to have the 'deepest' discount structure, as opposed to Raytec which may use a 'shallower' IT type discount structure. As such, Raytec may be the most expensive of the three (at least in this category). Here's a breakdown of the 3 manufacturer's longest ranging low-voltage IR illuminators:
LED reliability and proper exposure are two other notable areas. Below, we overview some key points and then expand later on this in the strengths and weaknesses section.
If it is important to maintain the maximum illumination distance over the life of the illuminator, Bosch's 'Constant Light' feature appears specifically designed to deliver this requirement. However, the additional cost premium for Bosch's illuminators can be a discouraging factor. Another option is to over-spec the distance for Iluminar illuminators and lower the LED power setting on initial deployment. This will create an artificial reserve capacity that can be 'tapped' as the LEDs lose distance over time. Keep in mind that this work around does not address 'acute' temperature related fluxes in LED output.
Surveillance applications where subjects of interest can occur through a wide range of depths within a scene are more susceptible to problems with over/under exposure. I.e., subjects close to camera/illuminator tend to be over-exposed, while subjects far from camera/illuminator tend to be under-exposed. In such cases, consider Bosch's line which features '3D Diffuser' (formerly 'Black Diamond') technology. This is the most purposeful and explicit enhancement dealing with such situations and involves lens properties which distribute light more evenly between foreground and background.
IR LEDs play an important role in overall IR illuminator performance. While significant differences exist among IR LEDs available in the market, our findings indicate that Bosch, Raytec, and Iluminar likely source their LEDs from the same manufacturer OSRAM [link no longer available]. In this section, we examine the options available and the offerings of OSRAM.
Two common options are available for IR LEDs: (1) through-hole (radial) LEDs and (2) Surface Mount Technology (SMT) LEDs. Through-hole varieties are generally cheaper, they are less efficient and produce less power than SMT LEDs. Power output is key as a strong relationship exists between LED power output and illumination distance. Through-hole LEDs are frequently used in less expensive offerings such as cameras with integrated IR. However, SMT LEDs are superior in many ways to through-hole LEDs, and are commonly used in add on IR illuminators.
Two key LED performance metrics should be noted:
The opto-semiconductor company OSRAM purports to offer some of the highest output IR LEDs available in the marketplace. The latest Platinum Dragon SFH4232 [link no longer available] LED has a stated power output of 530mW. To put this power output in perspective, OSRAM claims that through-hole (radial) competitors can only provide roughly 35mW in their best IR LEDs.
OSRAM attributes their better than 10x industry performance (in power output) to their ability to scale 'chip' sizes to 1mm x 1mm. Other LED manufacturers apparently are unable to scale from the smaller, more common 0.3mm x 0.3mm chip sizes to larger ones without incurring critical performance losses.
OSRAM also has a Platinum Dragon SFH4235 [link no longer available] LED, which has an output power of 950mW or nearly twice the output power of the SFH4232. OSRAM accomplishes this by 'stacking' two 1mm x 1mm LEDs into one package.
OSRAM also offers smaller, less powerful LEDs called TOPLED. OSRAM's TOPLED (SFH4258 [link no longer available]/SFH4259 [link no longer available]) LEDs are based on a smaller 0.3mm x 0.3mm chip size, and have a stated output power of 50mW.
Determining IR LED Type
While the type or IR LED used is quite important, determining what type is used is difficult. Rarely is this disclosed on data sheets and it is not simple to verify by looking at a product picture. Moreover, some vendors will attempt to obscure or hide their sources.
Strengths and Weaknesses to Consider
The following are a number of product differences we identified that might impact product selection:
High Voltage / Raytec Options
Regardless of vendor, the majority of illuminators surveyed are powered through low-voltage. In fact, both the Bosch and Iluminar IR products surveyed are exclusively low-voltage. While, only Raytec offers high voltage models. Raytec's use of high-voltage allows them to offer the greatest illumination distance of 1000 meters (5 degree beam). (Note it requires two units of RM300-PLT-AI-05 [link no longer available]).
Raytec adds notable features built into the power supplies of high-voltage units. Features such as pulsing, remote dimming, power boost, and timer control provide various levels of utility in certain applications. For more information, see Raytec's Pro Series PSU datasheet [link no longer available] and our section below on dynamic power adjustments.
Maximum Distances Claimed
All three manufacturers claimed a similar maximum distance for their longest ranging low-voltage model. Namely, Bosch's SLED10-8BD [link no longer available] claims 320m, Iluminar's IR919-A10-24 claims 280m, and Raytec's RM200-F-AI-10 [link no longer available] claims 300m (all distances for 10 degree). However, two of Iluminar's IR919 can be bracketed together to deliver a claimed 392m. While it appears Iluminar provides the greatest range on a low-voltage unit, lack of standard methods to determine illumination distances across vendors, make it difficult to judge 'real' differences.
Somewhat surprisingly, PoE models are not offered by all three of the manufacturers surveyed. PoE models, are available in Iluminar and Raytec portfolios. Whereas, PoE is not available within the Bosch line. Iluminar's IR312-A10-PoE and Raytec's RM50-10-IP [link no longer available] represent the longest ranging PoE IR illuminators from their respective companies (both models require PoE+ or 802.3at). Max illumination ranges are 95m for Iluminar's IR312-A10-PoE and 60m for Raytec's RM50-10-IP.
LED Life / Reliability
Maximizing LED life is an important but contested aspect of IR illuminators.
Bosch claims their feedback circuit compensates for LED output losses over time by increasing input power. Bosch uses feedback circuitry to monitor LED power output and increase input power, if needed, to maintain a relatively constant illumination distance.
However, Raytec claims that their elaborate heat management techniques are actually more effective than Bosch's overall. Raytec reports that all of their units are current controlled (rather than Bosch's power output controlled). Their LEDs are mounted to a metal clad substrate which they claim is the best heat transmission material available. They argue that Bosch's technique actually promotes LED degradation by 'driving' LED power output higher (causing increased current/heat).
Interestingly, Iluminar suggests that LED degradation is over-hyped and less of a concern given the improvements in LED technology and performance lifetimes, alluding to OSRAM performance tests.
We cannot assess these claims fully as testing this would be difficult and perhaps unrealistic given the long time frames involved in this aspect of performance.
Near Field / Far Field Exposure Levels
Given that IR is light, IR illuminated scenes can be overexposed (i.e., washed out). This is generally a problem when subjects are closer to the camera (as IR illumination levels will be higher closer).
Only Bosch claims an enhancement that explicitly deals with minimizing problems with near-field/far-field exposure levels. The technology is based on special lens (optical) properties. Essentially, IR is distributed more evenly between near and far field. Iluminar and Raytec do not offer a speciailized strategy to deal with this type of situation.
Certifications (e.g., UL, FCC, CE etc.) by 3rd party organizations provide unbiased, and standard methods to assess a product's safety, electrical and other conformances. Of the three manufacturers, we've found that only Bosch, and Iluminar list product certifications on data/technical sheets. Certifications are often preferred by any customer for any given application; moreover, in certain customer environments e.g., government, military, transportation,industrial etc. explicit certification requirements will likely be specified.
Raytec's Adaptive Illumination feature allows finer control of illuminator beam-angles and can thus be better optimized for varying camera FoVs. A specialized bracket with two or three illuminators enables this functionality on Raytec SKUs containing the 'AI' designation (majority of IR illuminators). In contrast, Bosch and Iluminar units are generally sold as single panel, fixed beam angle illuminators. Fixed angle illuminators do not offer the 'in-field' adjustability or ability to re-purpose illuminators for narrower/wider FoV applications.
Note that Raytec's Adaptive Illumination technique does not appear to address over/under exposure issues in deeper field surveillance applications. In contrast, Bosch's '3D Diffuser' technology is claimed to be an explicit approach to dealing with issues regarding near-field/far-field exposure levels.
Intelligence / Dynamic Adjustments
Raytec provides the most options to dynamically control LED on/off and power output levels. While all three manufacturers generally provide telemetry and D/N switch capabilities in their low-voltage offerings, these are merely on/off controls. On the other hand, Raytec's high-voltage Pro Series PSU can be equipped with additional modules to provide added 'intelligence' to an illuminator. One interesting feature, Power Boost, claims to allow a 50% increase in power output to temporarily illuminate areas 'normally' out of range of the illuminator. It can be triggered, e.g., when a subject triggers a PIR or other sensor positioned at the far reaches of a monitored area. Other features the Pro Series PSU provides are Perma-light, remote dimming, deterrent light, and timer control.
Note that Pro Series PSU is limited to Raytec's high-voltage line.
Currently all PoE illuminators surveyed do not support management capabilities, and no IP address is assigned to the unit. PoE units with management features could be a future development to watch. Theoretically, data connections over an IP network could be used to provide more 'intelligent' features or software integrations between illuminators and cameras/VMSes.
'Intelligent' Illuminators might provide the following advantages:
The drawback is that these features will not be available on longer ranging illuminators requiring more than the maximum 25.5W the 802.3at standard provides. The pace of future developments in both LED and PoE technology will likely increase the range of PoE illuminators, but to what degree is uncertain. Currently max PoE distances are roughly 3 to 4 times less that of max low-voltage ranges.
Developments leading to greater PoE illumination distances:
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