David Hammond, Samsung Techwin’s European Sales Manager, has worked within the electronic security industry for over 24 years. His career has developed alongside major advances in CCTV technology. In this article he puts forward a view that one particularly significant development – day/night camera technology – is now at a stage where it should be treated as an opportunity and not just a problem solver for difficult installations.

Visual information is invaluable in a wide range of applications and the positive elements of using CCTV i.e. the ability to remotely observe buildings, grounds, people, public areas, is widely understood. However, one element which is necessary for visual information to be gathered is light, and a lack of the required level of light can be disastrous for even the most advanced CCTV system.

CCTV systems ultimately face restrictions. They lack the huge intelligent processing capability of the human brain, and the advanced mechanics of the human eye. Surveillance equipment is also built to a cost, meaning that even if such capabilities could be replicated, the cost could turn out to be higher than the CCTV industry would accept. However, by using what technology we have in the industry, steps can - and have - been taken to ensure that usable video images are obtainable in low light environments.

Day/Night cameras have been used for some years to overcome the problem of varying light conditions. Most of these types of cameras use a switchable IR cut-filter in the camera to give best possible colour images during the day and maximum IR sensitivity at night.

However, when you look at images that are captured in very low light situations, what usually makes the picture unsuitable is the amount of “noise” that it carries. Noise occurs when AGC (Automatic Gain Control) attempts to compensate if the video signal is weak, but it is usually the graininess and snow-type effects that render an image unusable before the actual darkness does.

Noise in CCTV images is one of the most common causes of video material being considered as unreliable evidence, particularly in low light environments. Noise manifests itself as static or moving grain, and can render CCTV images useless long before they become too dark to be of any genuine value. Sens-Up or Frame Integration processing works on a similar principle to slow shutter speed photography, combining a number of scans of the image in order to gain greater light exposure. This is fine for static subjects, but any movement within the image will result in what is referred to as ‘ghosting’. Here, variations of movement can render an extremely blurred image.

If this noise can be removed, the images will still be usable even at very low light levels. This is the thought behind the development of SSNR, Samsung’s Super Noise Reduction. The SSNR technology makes images cleaner and sharper, eliminating the high levels of noise without creating ghosting or motion blur. Independent tests have shown that colour images with SSNR applied stay sharp and clean, even after colour information is lost due to a lack of light. This shows that SSNR reduces noise in colour images that are well below the usual standard signal strength of 1V peak to peak without the pictures becoming unusable for CCTV purposes. The technology is even more impressive when the camera is in monochrome mode.

Financial Benefits –

On large CCTV systems, a major part of the cost is attributed to the provision of hard disc storage and associated equipment. A requirement to store large amounts of video therefore creates an equivalent need for a large floor area to accommodate the recording element of a CCTV system, possibly within a security monitoring room. Extra costs are also incurred to provide power, ventilation, and ergonomics for operators and annual maintenance costs.

Cameras equipped with SSNR can therefore offer a substantial additional financial benefit. By reducing the noise from an image, the recorded file size becomes significantly less by up to 70%, when using MPEG-4 compression and 40% when using JPEG thereby reducing the size of hard disc required. With MPEG-4 this is the equivalent of recording up to three times more on a hard disc compared to a camera which is not equipped with SSNR.

When used in larger CCTV systems this could deliver an overall reduction of a project by 25%

The Opportunities -

With the cost/performance ration of day/night cameras dramatically improved, we at Samsung Techwin feel that these types of cameras no longer have to be seen as a problem solver. We believe they can be seen in a more positive light i.e. the ability to site cameras in locations where previously it would have been too expensive to do so because of the need to install supplementary lighting.

One example of this is in the use of domes. Conventional domes cannot effectively use IR technology as it is hard to get the IR to follow the camera’s direction and zoom. Domes that utilise SSNR reduce dependency on IR lighting....... The Samsung Techwin SPD-3300 dome can, for example, capture clear crisp colour images without the need for IR lighting and is therefore suitable for a wide range of applications such as car parks, industrial estates, retail business parks and airports.

Customers expectations in respect of the performance of CCTV cameras continue to grow, regardless of the application. With noise reduction techniques such as SSNR, you can now create CCTV systems which give excellent recorded results, even in the poorest level of illumination whilst maximising the storage capacity of your DVRs.