The security industry has long been synonymous with the term Closed Circuit Television (CCTV), but in fact the CCTV industry has been anything but ‘closed circuit’ for many years. For a long time now, analogue systems that use coaxial or twisted pair cable for transmission have benefitted from the ability to connect to networks via control equipment. Even with the most cost effective equipment, full viewing, control and administration of such a security system is possible via a PC connected to the Internet. However, the trend of plugging a surveillance camera directly into the network is one that continues to gather pace. As a result, IP and network security products are now the single largest contributors to the growth of the physical security market as new installations take full advantage of the benefits that operating over the network brings.
IP based surveillance systems allow users to gain maximum benefit from the latest generation of high resolution cameras that can deliver so much more than conventional analogue CCTV cameras, which typically generate images comprising of just 0.4m pixels. For example, depending on the field of view, a 1.3 megapixel camera can do the job of several analogue cameras as it can cover a wide area and then zoom in very close, to a distant object, without ‘pixilation’ appearing in the image.
It is perhaps worth defining the difference between the different types of high definition cameras. A megapixel camera is simply a camera capable of capturing an image at a resolution of 1 million pixels or more. 1.3 megapixel cameras are amongst the most common on the market and this figure equates to a resolution of 1280 by 1024 pixels. However, even though a camera may be able to capture images of 1 million pixels, it cannot be described as a true HD camera unless it complies with the widely accepted HD standard. This requires the camera to output resolutions of either 1920 by 1080 or 1280 by 720. Unlike standard CCTV cameras, an HD camera displays images in 16:9 format (widescreen) and has to be able to output images in realtime at 25 images per second. The 16:9 aspect ratio allows users to see a much wider field of view compared to the traditional 4:3 aspect ratio. In summary therefore, all HD cameras are megapixel but not all megapixel cameras can be described as HD.
HD megapixel cameras offer a lot more than just remarkable ‘evidence’ quality images and a helpful display aspect ratio. They also come with a range of other features which equip operators to respond more effectively to any suspicious activity or emergency. Most of these ‘added value’ features are likely to be incorporated into a camera’s DSP chipset. The Samsung WiseNetIand WiseNetII DSP chipsets, for example, have been designed specifically to allow users to gain maximum benefit from megapixel camera technology.
Although megapixel cameras can capture very detailed images, one of the benefits is that there is the option to simultaneously transmit images at lower resolutions, which include QVGA (320 by 240), VGA (640 by 480) and SVGA (800 by 600) and with multiple compression methods available, different authorised users are able to simultaneously monitor live images at one location, record video evidence at another or view live and recorded images on a smartphone.
At the same time, JPEG images of an incident can be attached to an alarm email notification with the additional facility of storing pre and post-alarm images on a camera’s internal SD memory card.
Of course, more often than not, users do not require the highest of resolutions across their entire site and it always comes back to understanding the operational requirement and then specifying cameras to match the specific requirements of the project. A security system will nearly always use HD megapixel cameras where they are required, coupled with standard resolution cameras for general overview purposes.
Intelligent video analytics
Another substantial benefit of most HD megapixel cameras is the use of Intelligent Video Analytics (IVA), which includes optical tripwire and enter/exit direction detection, as well as an appear/disappear function to detect the movement of objects. IVA also has a scene change tampering function which creates an alert if, for example, paint is sprayed on a camera lens or there is unauthorised movement of a camera away from its usual field of view.
If we look at the home and how the take-up of HD TV has gathered pace to the point that virtually every TV on sale is HD, I think we will see this trend in the security industry too. Average selling prices for HD megapixel cameras have reduced compared to last year alone, meaning more applications can benefit from higher quality images as the market gets more competitive. Samsung has recently introduced 4 and 16 channel NVRs capable of recording HD images, offering a cost effective solution for smaller IP based systems and the trend will continue down to smaller applications.
To read the full article download PDF