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Visual verification is becoming a ‘must’ throughout the security industry, with everyone steadily moving away from ‘blind’ intrusion alarm systems to ones that can be visually verified. While it is evident that cameras are essential to verify any alarm, the question is does it make the sensor redundant? Can the detection, lighting and visualisation be achieved by a single piece of equipment, and specifically the camera?

As much as camera technology and video algorithms have evolved, there is still both a risk and limitation in using a single technology to do everything. This is corroborated by leading cameras manufacturers investing in or acquiring sensor technologies as they understand the value of using a variety of technologies.

Detection in difficult lighting conditions

One of the benefits of modern sensor-led detection installations is that they don’t need light to perform. The same cannot be said for cameras.

By definition, a video device cannot process what it doesn’t see. Low-light cameras and video analytics featuring additional background filters improves the performance of video capture but camera manufacturers themselves warn against the limitation of detecting motion in difficult lighting conditions. This ranges from badly illuminated corners or areas on the scene, flashing/flickering lights, headlights, moving shadows etc all of which impact camera performance.

In an outdoor environment where lighting conditions are constantly changing, using physical sensors being a PIR, Active infrared, LiDAR, Radar or fibre optics device, will considerably reduce the risk of a false alarm or missed detection.

Detection speed

In simple terms, the more a device has to multitask the more time it takes to process a response. A camera has first to process a number of frames and pixels to be able to analyse the scene, filtering information, recognising and identifying shapes and their movement, all of which takes time.

Even with modern processors, the whole video image processing affects the speed and reliability of detection and some detection can be missed. For many customers, missing an event is considerably more dangerous than a nuisance alarm. The ideal scenario is to have no missed detection and no nuisance alarms.

Our sensors are using algorithms to process data and eliminate noise but without using any predictive elements which are sometimes used in cameras to reduce the processing time. This eliminates the risks associated with guess work and improves reliability.

Detection range

Detection range is a key element of system design as it determines the different alarm zones from pre-warning to critical. What is important is to make sure that the detection ranges are consistent throughout the day and weather conditions and that ability to detect is also consistent throughout the range.

If a detection range has been specified at 30m for instance, it is critical that detection is as accurate at 30m as it is at 2m or 15m.

Video devices will use depth of field and define how many pixels an object has within the ranged defined. In the last ten years, significant progress has been made on that front and higher-end cameras have the ability to be configured for variable object size depending on the distance. Mid- to low-range cameras usually don’t have this feature, and therefore don’t capture motion with accuracy at longer ranges. The depth of field can also be shortened by decreasing light intensity, cameras might not see as far at dusk as during daytime.

Our sensors are designed to capture motion consistently throughout the detection range

Benefits of sensor-led visual verification

The residential and light commercial markets are typically using mid- to low-range cameras, which will be more likely to trigger false alarms, especially if used in an outdoor environment. By adding a reliable outdoor sensor as a trigger to the camera, the level of nuisance alarms will drop dramatically.

It is a real opportunity with a very reasonable budget to improve the reliability of intrusion detection for that sector and also give the option to extend it to the outside of the building.

For commercial and higher security sites, not missing alarms is crucial, as well as keeping nuisance alarms as low as possible. Avoiding single points of failure and disruption caused by constantly having to reconfigure the systems to adapt to changing environments are also important factors that need to be assessed.

Using high-accuracy sensors together with good quality cameras managed by a high-performance video management system will give the best of breed to the end-users.

In the last few years we have worked in close cooperation with video manufacturers and we have seen the true value of bringing the two technologies together. It is now time that installers realised the benefits that such cooperation can bring to their business and their customers.