The new Redvision X-SERIES™ Dual Light dome / ball PTZ camera, which combines IR and white light LED illumination, has shown exceptional performance results in night-time tests. In this article, Paul Hucker, Managing Director of the UK-based CCTV manufacturer explains how recent developments in “Super-Efficient” LED lighting technology now enable 100m illumination ranges in IR or white light LEDs.
The test results demonstrated that, in total darkness, the Dual Light white-light LEDs enable successful facial identification, in full colour, from as far away as 40m away. Even when using the industry-standard NORMAN target from Tavcom Training, all details and colours are accurately rendered at 30m.
Both IR and White light LED technologies have developed dramatically to make this level of lighting performance possible. The new, super-efficient LEDs transfer a far higher proportion of their energy consumption to light, with far less lost as heat. Previously, large heat sinks were necessary to keep the LEDs cool and illumination levels high. Super-efficient LEDs need far smaller heat-sinks, meaning products or enclosures can be much smaller whilst having greater illumination capability at lower operating temperatures. This has had a significant impact on product design and development. We have been able to combine white-light and IR into a single product, sharing the same heat sink. Previously, this simply was not practical or even possible.
The Dual Light toggles between lighting modes automatically to suit ambient lighting conditions. In IR mode, the Dual Light operates in black and white and in white light mode it switches to colour. Super-efficient LEDs turn on immediately, with almost no latency. This has enabled the instant switching between IR and white-light modes necessary for PTZ dome applications. Toggling also has the added benefit of extending the operating life of LEDs because they are only on for half the time!
Light mode selection is as much about the deterrent effect of white light and its effectiveness in warning away intruders, as it is about producing high-quality colour images in poor ambient lighting conditions. A product that combines both lighting technologies is of far greater value in CCTV applications than separate units. Specific IR and white light settings can be designated to each of the Dual Light’s 100 presets, whether in night-time, day-time or weekend modes. This means, for example, we can avoid dazzling drivers in public space applications by using IR light, yet can illuminate would-be intruders in white light mode to prevent a break-in. It is important that users are fully aware of the potential hazards of white light, such as risk of dazzling, as well as the benefits. To this end, we have developed a “dark-zone” feature to define specific areas where the white light LEDs are deactivated to prevent nuisance or hazardous operation.
All LEDs degrade over time. The lifecycle of super-efficient LEDs is usually quoted as 50,000 hours, which is almost 6 years of continuous operation. There is an initial ‘BURN IN’, where the LED is brightest, but this brightness fades, before a far slower fading takes place over the rest of its life. This early brightness can be offset by reducing power to the LEDs. Power can then be slightly increased over time to keep LED performance consistent. The latest super-efficient LEDs we use have almost no burn-in, keeping power consumption to the absolute minimum.
The ability to adjust LED brightness to suit the environmental conditions and scene view is important. We reduce illumination levels to avoid flooding a camera scene with light and we use a number of LEDs to create an even spread of light across the scene, avoiding any spot-light or “port-holing” effects. Brightness is also adjusted in relation to camera zoom and scene content, with zoomed in scenes typically requiring less light than zoomed out, distant scenes.
Super-efficient LED technology is a revolution in night-time surveillance. Our cameras can produce evidential quality images in either white-light or IR light modes for scenes of up to 100m with facial identification at 40m. This level of performance was simply not possible as recently as 2 years ago.
Contact Redvision on 01420 448 448 or visit redvisioncctv.com for more information.