Burglary, shoplifting, internal theft, collusion, credit card fraud, ram raiding and violence against staff are among the challenges of retail security managers, writes CCTV manufacturer Samsung Techwin.
CCTV has consistently proven to be a tool for security managers. The good news is that CCTV technology is continuing to advance at a dramatic rate. In fact, security managers, borrowing the famous words of Harold Macmillan (in another context) ‘have never had it so good’when it comes to choice of CCTV available. You could in fact feel swamped by the seemingly endless choice of cameras as there seems to be so much available. Using a sporting analogy, you may be allowed to use up to 18 golf clubs but it would be much easier if you could achieve that perfect round of golf if you only had to decide which to use from a handful of clubs. Fortunately if you are into "one stop shopping" manufacturers such as Samsung Techwin can provide the solution for any application by the use of just a handful of cameras. And your caddy (your installer) will be more efficient as he will have less spares to carry or cameras to service and maintain. We have come a long way from the days when all that was available were expensive monochrome cameras which produced grainy images. Since then major CCTV manufacturers have invested in R & D and the results have been major advancements in the quality of CCTV cameras. Initially these advancements offered increased functionality by mechanical means. More recently the digital revolution has allowed a dramatic improvement in the functionality of CCTV cameras to provide a high quality solution for any application.
Lighting
One of the biggest improvements in CCTV camera technology has been in the understanding of how to deal with variable lighting conditions. How well for example will a camera perform when pointing at a store entrance and exposed to direct sunlight? Back light compensation and auto white balance are just two of the functions that are available today that overcome this particular type of problem. However the biggest challenge facing CCTV manufacturers has been how to deal with poor lighting conditions. How well will a camera perform at night when the store is closed or where a car park is poorly lit? As retailers aspire to achieve a higher level of performance from their CCTV systems, it is not surprising that a camera’s ability to deliver high quality images in low light has become an important aspect of CCTV system’s specification. So what advantages does all this advanced technology offer retailers? Retail come in many shapes and sizes, each with their own methods of operation, each with their own security problems. However a common problem is theft from storerooms, warehouses and distribution centres. At night when staffing levels are low a dishonest employee on their own or in collusion with others has an opportunity to help themselves to valuable stock. They may do so under the impression that CCTV cameras are unlikely to produce recognisable images when the area is in darkness. The introduction of technology such as SSNR (Super Noise Reduction) SV III technology as well as Wide Dynamic Range capability ensures that with correct placement of cameras retailers can identify the culprit and eliminate the opportunity for "back door" theft. There are variations and options to each camera such as the choice of lens and power but essentially you need only to select from only three different cameras to find a match to your specific requirements.
Physics
The reflection and refraction of light are basics of physics. Without some level of light we would be unable to define any objects or activity visually. Without being artificially created, there are very few places on earth that have no light whatsoever and that is why we can often see in very low light, once we have become accustomed to the dark. Unfortunately, CCTV devices do not have the phenomenal processing power of the human brain! However, usable video images are obtainable in low light environments. For an effective choice of camera for 24-hour CCTV, there are many factors: first, the objectives of the system. What quality recording is required? In many systems, the recording system will denigrate the image quality available from the camera because archiving is required for 31 days, so resolution and frame rate levels are compromised. It is thus essential to get the best possible image to start with. Technology such as SSNR (Samsung Super Noise Reduction) will help by filtering the image to provide cleaner images with smaller file sizes and optimise capacity of DVRs. The camera that can give perfect, noise-free images in pitch darkness is not yet commercially available for day to day security systems, so light sources that are available at night, if any, in addition to moonlight and starlight, will dictate the type of camera used. Common light sources such as low-pressure sodium (street lights), Tungsten-halogen (flood lights) and Infra-red lamps, can all be used to balance light pollution with available camera technology, to meet the system objectives.
CCD chip
There are two main objectives when considering creating a CCTV system for low light environments. First, to try and channel as much light as possible onto the CCTV camera’s CCD chip. Second, to minimise the negative effects created if sufficient light does not actually reach the Charge Coupled Device (CCD). The vast majority of modern CCTV cameras use a CCD chip to produce the images that are viewed on the monitor screen or recorded on a DVR. The technology used by CCDs has been developed over many years, and manufacturers of chips such as ourselves are still looking for new ways to make the chipsets deliver better performance, especially where lighting is not consistent or guaranteed.
Noise nuisance
Noise occurs when AGC (Automatic Gain Control) attempts to compensate when 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. If the noise could be removed, the image would still be usable. This is the thought behind the development of SSNR. The 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. If a CCTV system is surveying an area where crisp, clean and detailed images are required in all types of illumination, cameras with technology such as SSNR can solve many problems that standard cameras will struggle to overcome. The SSNR (Samsung Super Noise Reduction) technology is now in its second generation and comes as a standard feature in a wide range of Samsung Techwin’s CCTV cameras. Regardless of the make or specification of the DVR installed, the SSNR technology will improve the quality of the recorded images by significantly removing both random and fixed noise from images.
Change cameras, not DVR
In real terms this means the image that you are recording is clearer, sharper and retains more detail. By reducing the noise from the image, the recorded file size is significantly less, reducing the required hard drive capacity by up to 70 per cent when using MPEG compression and 40 per cent when using JPEG compression, thus enabling you to increase archive time, improve your compression quality and increase frame rates without changing your DVR. It is perhaps worth clarifying the actual function of some popular names for different low light camera types, in order to specify the right camera type with the right type of ancillary lighting.
Day-night
Colour-mono cameras switch between colour mode and monochrome mode and have been used for quite some time to provide 24 hour surveillance. They have often given poor colour rendition because the sensitivity of the CCD sensor to infra-red (IR) affected the colour image, even though IR response is reduced. Day-night cameras are similar to colour-mono but use a switchable IR cut-filter in the camera to give best possible colour images in the day and maximum IR sensitivity at night. These cameras, such as the Samsung Techwin SDN-721A offer the best of both worlds without compromising performance. They can be used with any common light source and are normally suitable for use with IR lamps up to 900nM. An important element when selecting the appropriate camera is the spectral range of the camera and how it matches the wavelength of the light source. If there is IR lighting on site, it is essential to ascertain the light wavelength of the lamps and check that it is within the spectral range of the chosen camera.
Day-night CCTV cameras have been available for some years but have been considered too expensive for most CCTV installations particularly when a large number of cameras are required. The makers of the recently launched SDC-415 camera claim to be the first day-night camera to be affordable for virtually any application. The SDC-415 produces colour images during the day but when lighting levels fall below 0.3 lux it switches to night mode to deliver ultra clear monochrome images. At the heart of the SDC-415 is SV III, a new image processing chip that analyses images captured by the camera and by taking into account the prevailing lighting ensures that quality images can be displayed and recorded at all times.
Despite its low price the SDC-415 will provide a solution for 80pc of applications, it is claimed. It is however limited in its ability to cope with infra-red light and so where that is important we would recommend our SHC-721A, a Wide Dynamic Range Day/Night colour camera. Although a little more expensive than the SDC-415, its performs extremely well when working with Infra-red lighting. And when you require a colour camera to work at very low light levels without the use of any artificial lighting, the SHC-730, a Wide Dynamic Range Day/Night camera that incorporates SSNR and SV III produce superb quality images (in sens-up mode) down to an incredibly 0.0004 lux– a camera that literally "sees in the dark".
So with all this technology at your disposal, perhaps now there is time to achieve that perfect round of golf!
