IRE and Lux Light Levels

January 12th, 2009

IRE for CCTV Lux

What does IRE mean when quoted with Lux light levels for CCTV cameras?

We’ve noticed that many people seem to be a little baffled by this mysterious occasional mention of the term IRE, so we thought we’d just write a quick article to explain it in lay terms for you.

There is a good technical explanation over on Wikipedia, but as often happens it is a bit too technical if you are starting from the point of having no idea!

IRE stands for Institute of Radio Engineers, but that’s not important, you want to know what it means.

Well, keeping this within terms easily understood by lay-men:

The squiggly line above represents a composite video signal.

We refer to a good signal as being 1 volt peak-to-peak.

The Institute of Radio Engineers came up with the term IRE to represent the composite video signal in percentage terms i.e. 100IRE equals 100%, a full (good) signal.

Now the buyer beware bit. Just about the only time you see IRE quoted is when a manufacturer is trying to apply specmanship i.e. they are claiming that their camera can ‘see’ in very low light levels, but in fact it only does so poorly, and produces a less than good composite video signal.

For example 0.05 Lux (30IRE) means that in light levels measured at 0.05 Lux the camera will produce an image, but it’ll be a poor one, with a composite video signal level at only about 30% of what it should be. Effectively this would be a fairly useless image, and perhaps the camera is only really useful down to a higher lux level of say 0.5 Lux …

Of course, due to our human tendency to ignore the bits we don’t understand, it makes for quite clever marketing really; most folk just read the specification, see the incredible ‘see-in-the-dark’ capability indicated by the very low lux light level claimed in the specification and proceed to buy the camera.

To gain a better understanding of relative lux light levels take a look at our free chart.

Theia wide-angle CCTV lens demo images

January 12th, 2009

Theia wide-angle CCTV lensesTheia’s rectilinear lenses allow you to monitor a wide-angle field of view without any fish-eye distortion at the edges.

Over at his new blog Nick St Clair has posted some useful demo reference images captured using Theia lenses which provide picture proof of their effectiveness. Click the images to enlarge and see full megapixel detail.

Theia wide-angle CCTV lenses are available from our UK IP CCTV web shop.

Hard Disc Drive Storage for CCTV Surveillance

January 10th, 2009

veracity logo

Veracity mentioned this article on their website in an email I received recently; it’s a good write-up on the use of hard disc drives in modern CCTV video storage. The article isn’t new but it provides a lot of useful information and we think it’s worth pointing it out to you:

The most obvious current trend in video surveillance is the slow evolution from analogue cameras to IP cameras. Industry vendors of recording systems appear to be divided into two camps : the sceptics, who are wondering when the IP video revolution is really going to take hold, and the informed, who know it is already here and are just getting on with it.

Although the IP video segment of the UK market is currently only around 15%, it is growing rapidly. In Europe, where analogue CCTV cameras are not so entrenched, the growth rate is even steeper.

One of the things that has held back IP video systems up to now is the lack of any real reason for users to switch, even for new installs. What would they have gained, bar a little increased flexibility ? Now, in 2007, the story is quite different : most well-designed IP cameras are progressive scan, at long last leaving behind the problematic interlaced image legacy of the broadcast TV standard. Further, and more importantly, mega-pixel cameras (with resolutions way beyond HD TV) are now here and affordable. At long last, mega-pixel cameras provide the compelling reason to switch to IP-based systems. The improvement in image quality offered by high-quality mega-pixel cameras in nothing short of dramatic, even breathtaking. Another problem which has held back adoption of IP cameras is the vast amount of legacy co-axial cabling installed in existing systems. However, several vendors are now offering Ethernet over-coax solutions, so this is no longer a barrier at all.

Well worth a read, to aid your understanding of the use of big HDDs, RAID storage and potentially high disk failure rates.

2TB SDXC Cards – Coming Soon!

January 9th, 2009

Two TeraBytes on an SD card!SDXC Card

That’s incredible.

Spotted over at ZDnet as just another new gadget announcement from the CES show in Las Vegas this week.

The SD Association have announced a new SD XC format which will be capable of storing up to 2 TB (a TeraByte is 1,000 Gigabytes).

What’s more, read/write speeds of up to 300 Mbits/second are on the product roadmap.

From the SD Association website:

A 2 TB SDXC memory card can store 100 HD movies, 480 hours of HD recording or 136,000 fine-grade photos. Faster bus speeds will enable professional-level recording in compact consumer camcorders and increase the number of frames shot in a second with SDXC cameras.

Put one of these in the back of a surveillance camera and you’ve got yourself a built-in 20-day HD Digital Video Recorder!

There’s a good write-up over at the CES Show site.

We shall have to wait and see how long before any manufacturer actually releases a product that can live up to the potential in this new specification – product being; either SDXC cards with the above capability OR devices able to utilise it …

7-megapixel, 180-degree HD network camera

January 9th, 2009

'Digital Window' D7 Camera from Scallop Imaging

HD Network Camera delivering 180° seven megapixel images!

We found this over at

The D7 is a 7 megapixel camera capable of processing 100 megapixels of information per second. It also doesn’t have just one lens, instead incorporating 5 separate lenses allowing for a full 180-degree capture at 15fps.

As well as the high resolution capture, the camera doesn’t need a connection to a power point as it is powered over Ethernet. That means with a single cable you can have a very wide-angled security camera capturing HD footage.

Great for wide-angle CCTV surveillance!

Scallop’s Press Release says:

A single 180° Digital Window camera feeding into one DVR port can replace multiple conventional cameras for most security applications, enabling significant cost savings and faster ROI upon deployment. Customers benefit from an extraordinary increase in capability, at lower cost and lower bandwidth requirements than present IP camera solutions. The Digital Window camera delivers a down-sampled 180° situational awareness view simultaneously with a full resolution zoom window.

Digital Window also offers:
• Excellent facial recognition, in place of existing wide angle solutions that produce only a blur;
• Instant pan and zoom, with no camera movement;
• No fisheye distortion or blind spots;
• paired units can provide a 360° field of view;
• Compatible with video analytics software;
• Power over Ethernet (PoE);
• H.264 image compression; and
• 15 fps video streaming with seven megapixels of detail over standard 10/100 Ethernet networks.

Visit the Scallop Imaging website

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