Using budget IR illuminators without getting a hot spot

[CCTVguru]

As more and more retail shops sell budget video cameras, the level of specialized information given to the client is becoming less leading to an increase of almost worthless coverage.
Many low cost video cameras now have built-in Infrared lamps located in a band around the lens, which probably appears to be an excellent idea as these cameras can see after dark. In fact some give a specification of 0 lux. While it is true that they can work with total darkness (0 lux), what's not mentioned is in what distance. From the shot shown here, it is easy to see clearly that it is a garden path but see the severe variation in the light. At around 3-4 metres the light is so bright that the bush on the left of the pathway is washed out. The very same would occur to a person standing on the path. Around two mtrs of that, we have almost no light, causing the surveillance camera to not give a good even differentiation across the image.

As a result of this, I do not recommend working with video cameras with in-built Infrared because they cause a bright spot in the centre of the picture and not much towards the edges, causing an over exposed part of the picture in the middle, making a person impossible to recognize.

This isn't limited to infra red lighting as very much the same results take place under normal white light as can be observed from this illustration showing poor lighting in a shopping center. Also this link on lighting for

Infra red illumination is a wonderful tool to the security industry because it permits a surveillance camera to see in total darkness as though it was day time. I have been inside sites where I was not even game to walk for fear of tripping while in the darkness yet the surveillance camera could see clearly. This is using a reasonable quality of surveillance camera and Infrared light source. If you ask me, typically budget security cameras have Infrared coverage for a few mtr's and as can be seen in this picture, give you a very grainy finish outside of the Infrared hot spot. Better outcomes are possible by using a reflected or indirect IR light source as I will show you next.

First a few clarifications about IR illumination.

* For IR to end up being useful to a camera, you need the camera to run in B&W .
Most of the less expensive surveillance cameras claim they can do this but are in fact always in colour setting. They simply shut off the part of the video signal that produces the colour, known as the colour burst. A proper day & night camera has something called an IR cut or sweep filter, which during the day cuts out all IR light from hitting the CCD or CMOS sensor.
Why would we want to do this? Due to the fact Infrared light combined with color light will cause a couple of challenges. The foremost is very hot materials show up grey because they're emitting infra red energy. So a black street in the hot months appears gray. The other is because white or visible light possesses a different wavelength to IR, they need to be focused differently on the image sensor, causing the scene not to be sharp. This is well documented within one of the best books about video surveillance, simply titled '' by Vlado Damjanovski.


* IR Illumination isn't visible with the human eye when cast over a surface. However a number of illuminators can give off a dull red light when you look directly at them. These are working in the 840-880nm wavelength (Defined by the particular LED model you select), which is in the higher edge of what the human eye is able to see. If you are using IR LED's in higher wavelengths close to 940nm, no visible light is visible but not all cameras are as responsive to this wavelength.

Moving on to making use of Infrared lighting whilst not creating bright spots in the scene.

The ideal option is don’t work with a low cost IR light but I appreciate that many of my subscribers are working in the value conscious end of the market. However for interest sakes, a high quality IR illuminator very much like those I have used in prisons can be purchased from vendors including Rayled & Microlight, that have some terrific advice on their sites. Several low cost products including the IR110 will offer decent outcomes when following the tips down the page.

The best way to avert any spot from your budget IR illuminator is not to point it straight at what you wish to see. More advanced illuminators spread out the light more consistently and also over a much wider region so may be pointed directly at the area while not producing a hot spot. As an alternative make use of reflected light by means of an adjoining surface area like a wall structure or roof. By using an Infrared lamp separate to the camera and pointing it on a forty five degree towards the roof or off an adjoining wall reflects the light much more consistently across the scene but it does lower the length of coverage.

I've used this method extensively in compact areas as well as prison cells but nearly as good outcomes can be had externally or even in halls where there is often a surface alongside the camera. Basically any surface apart from the location where the camera is protecting is fine.

Remember that the IR light does not need to be right next to the surveillance camera either. If your camera will be viewing an object ten mtrs away, place the illuminator closer to the location so a larger level of light is thrown exactly where it really is needed. Light brightness gets the inverse sq . law used on it as detailed in the previously referred to CCTV book. Essentially, if your illuminator is 10 mtrs away from the object being covered by the camera, it's going to provide ¼ as much light as it will when installed five metres away.

[MegapixelMan]

HI Tim,

Great information and it good to see people are looking the right solution not just the right price. I use RAYLED illuminators from and find them to be excellent for customers that need Illuminators in most cases I still prefer customer to increase lighting if possible.

What most poeple arn't aware of is that the camera plays the biggest part of IR Illumination as most cameras with IR spec a lux level of .0 but the actual IRE level of the camera is alot worse then that.

I only use quality proven cameras for low light situations..

Bosch Dinion 2X is a great Camera low light with WDR
Sony SSCG923 is another great low light camera with WDR.

For a cheaper Alternative the KOBI cameras are good for the price.

CAM98TWD and CAM38TWD and well priced with a 3 year warranty and Sony Effio Chipset.

Keep up the good work Guru.

[CCTVguru]

Sound like you have a good understanding of cameras.
Just don't mention Kobi around me please.

[MegapixelMan]

I know what you mean years ago I would have not touched KOBI as I had issues with DVR's and the KOBI ( Crow Panels ) well say not more....

Now I have to admit that KOBI ( now called Video Security Products ) has come of age...

I deal with Dan at the QLD office and he is very good with IP and they have a massive range including SONY IPELA, RAYLED, MESSOA, QNAP, EXACQ and a deccent Analogue Range.

Not blowing their trumpet to much but companies all go through bad times and I recommend you try them especially in IP.. Make sure you speak with Dan though as he is the most knowlegable.

Where abouts are you based ?

Jamie

[Privatteer]

They have picked up Exacq?
Have to remember that liked the system, didn't like the importer I brought it off.

One thing to mention that many people miss. Some of the cheaper IR lights, including inbuilt in cameras are only rated for a low number of hours before they start failing.

[intelliGEORGE]

Some of the cheaper IR lights, including inbuilt in cameras are only rated for a low number of hours before they start failing.

That's exactly right. Also, the term "Sony CCD" gets used far too often which I personally believe they should change.

Sony has 5 grades of CCD's. The first grade is generally reserved only for Sony professional CCTV cameras. The lowest of all can be found in you run of the mill eBay kits.

[CCTVguru]

One thing to mention that many people miss. Some of the cheaper IR lights, including inbuilt in cameras are only rated for a low number of hours before they start failing.

Do you have any info on the number of hours for the different brands ?

[MegapixelMan]

Hi,

On the Specs sheets of most cameras it will tell you the hours of usage and many are rated about 8000 hours at 12 hours a night and 365 days a year is about 4380 hours per year.. So you get aboiut 2 years life...

Personally I have find the after about 2-3 years you will lose a percentage of LEDS depending on the camera manufactuer.


EXACQ Software

This is cross platform for MAC's and Windows also now looking at the blog have added Sentry360 Cameras so the software must dewarp the images.. NICE..

Privatteer I can recommend Video Security Products as a supplier as they are helpful, well priced and now have a wide selection including Sentry360, Korenix, Exacq, and SONY !!!! I like eeeeee

[Drift]

That's exactly right. Also, the term "Sony CCD" gets used far too often which I personally believe they should change.

Sony has 5 grades of CCD's. The first grade is generally reserved only for Sony professional CCTV cameras. The lowest of all can be found in you run of the mill eBay kits.

This may be the case, however with Sony sensors typically providing better image quality than their competitors (provided of course the back electronics is up to scratch) it's a fair point to advertise.

Sony of course could release an accredited dealer/partner program the likes of which would ensure strict standards pertaining to the use of their products are adhered to, but China being the worlds copy greatest copy machine would soon ensure the trade marks/seals of such a program adorned anything that loosely resembled accredited product.

But I digress.

A lot of the built in IR illuminators (and stand alone for that matter) suffer from poor design in their driver circuit. Some with no driver circuit at all, simply relying on a resistor to limit current, thus controlling brightness. The problem with this is that in an attempt to eek every last mm of range from their devices, manufacturers are running their LEDs well outside of the component manufacturers specifications thus significantly reducing the life of the device. The typical MTBF of a good quality and correctly utilised high intensity IR LED ranges from 20000 to 50000 hours depending on the manufacturer. However, as a result of the markets thirst for 'cheap and cheerful' product, this is often not the case in that, as mentioned above, a significant number of devices are failing exceptionally prematurely.

Until such time as the majourity of the market in AU, that being domestic and SME, shifts their motivation from price to quality, this is unfortunately just another small area of the industry set to continue to suffer.