Designs on domes

CCTV cameras are very MUCH IN THE frontline of the fight against crime. Whether they’re keeping an eye on staff pilfering in a retail environment or watching criminals attempting to break-in to a motor dealership under cover of darkness, those cameras also offer the most visible indication to potential offenders that a given area is being monitored.

Of late, dome cameras have been in the ascendancy in comparison with their more traditional monitoring cousins. Ask any security manager who visited this year’s IFSEC Exhibition at the NEC and they’ll surely concur. In the UK alone, the dome camera market is now said to be worth £90 million. Expectations are that this figure will increase by at least 10% per annum over the next four years.

The proliferation of PTZ and fixed domes has been driven by a number of factors, most notably their ability to be used covertly (particularly in the retail and leisure sectors where security managers will prefer a less obtrusive form of surveillance). Domes can also blend in with interior and exterior designs, to the extent that criminals aren’t necessarily aware they’re actually being monitored.

Most importantly, domes are now available at a price-to-performance benefit ratio that far outstrips the corresponding figures for conventional fixed cameras. That alone should interest many a security manager, and certainly those who are operating to tight budgets.

Turning domes inside out

The flexibility of specifying domes becomes increasingly apparent during the installation phase on site. The units may be recessed, surface-mounted or hung from the ceiling, mounted on internal and external walls or even fitted inside vehicles (as has been the case with several trial schemes involving local bus companies, for example). Some of the most common applications include banks, retail outlets and malls, as well as hotel reception areas. In fact, think of a location or a way to install a camera and, in all probability, there will be a dome that fits the bill.

Increasingly, dome cameras are being fitted not only as active surveillance tools but to help in securing premises against criminal attack. In practical terms, a single dome camera is able to provide 360 degree coverage of an area. This means that domes are seen as a cost-effective method of replacing perhaps four or five conventional cameras.

In the past, domes were largely restricted to indoor use, and many CCTV consultants wouldn’t specify them for external installations. That situation is changing, though. A drive through any business or technology park underlines the growing importance and number of exterior domes – mainly attributable to the now widespread availability of vandal and waterproofed models designed to the international IP66 standards (the latter a necessity given the unpredictable British climate).

The robust qualities of the latest domes – with the widespread adoption of materials such as polycarbonate for the camera ‘bubble’, locked to a die-cast aluminium outer housing – also makes them particularly attractive for exposed town centre environments where they’re likely to face tampering and attack courtesy of vandals. Some of the newer armoured domes have even been known to withstand blows from a sledgehammer!

As more and more domes are being adopted for external monitoring projects, it’s highly important that the camera units themselves can deliver effective performance in low light conditions (particularly where the uninterrupted security of a given building is of the utmost importance). This requirement is now being satisfied with the availability of specialised day/night cameras which are able to provide a low light monochrome image at night with sensitivities down to 0.1 lux – all thanks to the use of infrared technology.

Visual aspects of monitoring

Dome cameras have certainly revolutionised the aesthetic look of CCTV systems, being very much the preferred architectural surveillance solution. In the early days few security professionals would argue that CCTV cameras were in any way subtle. They adopted the familiar shoebox appearance, a shape driven more by necessity than aesthetics. The potential to hide such cameras was limited. Not surprisingly, their sheer bulk restricted where they could be successfully installed.

Thankfully, the advent of digital technology has meant that dome cameras are becoming more compact and visually appealing.

If there were to be a camera ‘beauty contest’ then low profile domes would surely win every time. They just look better, and are definitely not as intimidating or obtrusive as a fixed camera in a standard housing. These characteristics mean that they will not detract from the architecture or visual impact of a building (whether you’re talking about the entrance to a prestigious office development or the inside of a hotel lobby). Dome cameras also lend themselves to surveillance applications in conservation areas, where they easily blend into the background.

From a practical standpoint, domes are better suited to covert surveillance and tracking than are more conventional cameras. Not only is the dome less obvious than a ‘boxed’ camera, it’s also difficult for observers to determine where the camera is pointing at any one time, giving the impression of a much wider surveillance coverage. Users can also see areas which they would not have been able to see without a number of conventional cameras.

From a practical standpoint, domes are better suited to covert surveillance and tracking than are more conventional cameras. Not only is the dome less obvious than a ‘boxed’ camera, it’s also rather difficult for observers to determine where the camera is pointing at any one time

Obviously, issues associated with the privacy of individuals can and will crop up in mixed commercial/urban environments. The Human Rights Act may come into play. Manufacturers have addressed this ‘problem’ on behalf of end users through the introduction of programmable privacy zones (typically there are 24 or more of these on the higher specification dome units) which protect innocent members of the public by partially – or totally – blocking out specific areas in an image. Once these distinct sections of the image are obscured, it’s obviously important that they remain in proportion to the zoom ratio of a camera otherwise critical areas of surveillance may inadvertently be obscured.

Faster speeds, more angles

The latest domes move faster and through more camera angles than traditional PTZs. To set this in context, the rotational speed range of a high end dome is variable, from around 0.05 to 330 degrees per second, with a 90 degrees per second tilt (IMS Research, 2003). This means that PTZ domes are capable of delivering pretty much unlimited tracking possibilities for operators in pursuit of a suspicious character in a town centre, car park or in the vicinity of a business premises.

Indeed, the most advanced domes incorporate an auto-flip facility such that the camera module is automatically rotated through 180 degrees as the dome tracks objects passing directly underneath. This ensures that the image rendered always remains the right way up.

As users demand that domes are able to cover wider areas, this places ever-increasing demands on manufacturers to ensure that their cameras can accommodate these changing requirements. Positional accuracy based on a reliable mechanism has become a critical issue, even more so with the high optical zoom levels which result in a much narrower field of view at full zoom.

This requirement is also underlined by the number of predetermined positions or pre-sets (sometimes as many as 250) now available on certain cameras, with models having to repeat positions down to an accuracy of 0.1 degrees to be truly effective.

To address this requirement, some dome manufacturers have developed ultra-rigid, die-cast aluminium mechanisms. They offer greater precision and repeatability than cheaper products based on plastic materials which are more prone to distortion through general wear-and-tear, etc.

Obviously, the growing number of dome camera installations will impact upon other elements of security. Domes may be integrated with alarms controlling pre-sets, making rapid reaction to incidents a reality. A good example of this is remotely-monitored CCTV, whereupon on-site cameras are linked – typically via an ISDN line – to a Remote Video Response Centre (RVRC). Here, trained operators provide event-driven monitoring of a specified area, alert the relevant authorities of any incidents that should occur and then issue verbal warnings to intruders.

When applied correctly, this type of security set-up has the potential to prevent criminal damage and minimise disruption to business. Dome cameras have certainly excelled in such integrated security projects. In practice, external alarms from PIRs and beams instantly move the dome camera to survey the area where the alarm has occurred. This method of moving to a pre-set position means that an incident being relayed to the RVRC shows exactly what happened during an alarm incident, the dome camera(s) having captured the relevant images.

With a number of conventional cameras, the operator may have searched many areas before apprehending the culprit. An operator at a RVRC can take advantage of these pre-sets, rapidly searching the key areas that a dome covers in a fraction of a second.

If you’re talking about dome cameras with pre-sets, in a detector-activated CCTV environment it’s vital that the latest BS 8418 Code of Practice is brought into play. Such domes should be seen to be multi-positional fixed cameras, and have separate detector indicators (to signal back to the control equipment for each pre-set, for instance).

One eye on the future

Looking to the future, dome cameras are certainly here to stay. As has been proven time and time again, the beauty of these cameras is definitely more than skin deep.

The reality of the situation – with the technology applied to domes constantly being subject to revision in order to enhance positional accuracy, low light performance and durability – is that such cameras are more than capable of delivering cost-effective security solutions in a multitude of environments.