Security in 3D: a closer look at “Time of Flight” technology

In this article we examine a promising new technology known as “Time of Flight” (TOF) 3D imaging technology and how it can be used to improve the capabilities of your security system.

What is “time of flight” imaging technology?

TOF cameras generate three dimensional images of environments by shining lasers on objects within an environment and analyzing the reflected light. The name "time of flight" is used because the camera measures the difference between the time that individual particles are reflected back to the camera and use this data to construct a full 3D picture of an object using computer software. Because TOF cameras can generate up to 100 images each second, they are also able to track the movement of three dimensional objects through space with extreme accuracy.


Versions of this technology have already attracted mainstream attention, such as the popular “Kinect” device developed by Microsoft for their Xbox games console. However, 3D imaging technology is potentially a highly useful addition to the security systems of organizations in a variety of sectors as well.


How can TOF cameras improve security?

TOF cameras appear to have significant advantages over traditional surveillance cameras and video analytics in several ways, especially for areas where it is important to track the movement of people and objects accurately. This is because surveillance cameras only record visual data in 2D, which limits the accuracy and potential sophistication of video analysis software.


In contrast, TOF cameras process visual data in three dimensions. This means that TOF cameras can theoretically track the movement and location of objects and people with unprecedented precision, including subtle movement changes and even changes to the shape of a monitored object. For this reason, TOF cameras are potentially capable of performing people counting, anti-tailgating, people tracking and valuable goods monitoring functions much more effectively than traditional surveillance cameras and video analytics.


Let’s look at some of the possible security applications of TOF cameras:

Monitoring valuable Items

Using TOF cameras, security staff can monitor not only when a valuable item is moved, but also monitor a three dimensional space around the object. In this way, they can receive an alarm notification even before the object is tampered with or removed.


With this virtual 3D perimeter around an object, valuable items can also be displayed without the need for glass cabinets, thereby enhancing the visual impact of the display. Security staff for luxury retail stores, museums and other sites that display valuable items in public may therefore want to consider whether to incorporate TOF cameras into their surveillance systems.


People counting

Because TOF cameras should be able to detect the precise shape of the human body using 3D imaging, they have the potential to perform a highly effective people counting function. Providers of TOF camera systems claim that the technology can be used perform real time people counting, people behavior analysis (movement trajectories and loitering etc.), monitoring of entrance into unauthorized areas and many more.


This function may be highly useful to shopping malls, retail outlets, museums, entertainment venues and any other site with a high visitor volume.


Tailgating is when an intruder follows another person who has been granted access to the premises and enters the site after they are granted access before the access controlled door closes in time. This is a major security concern for high security sites such as R&D centers, data centers, prisons and bank buildings.


Again, TOF cameras may be able monitor and prevent tailgating activity with a high degree of accuracy. They are also potentially able to monitor alert security teams to other undesirable behaviors. For example, by monitoring 3D space around a turnstile, TOF camera systems could detect when an intruder jumps over a turnstile barrier, rather than passing through the gate in the authorized way.


The last word – are time of flight cameras the right choice for my security system?

ICD sees considerable potential in time of flight technology and we anticipate that its applications for security operations will continue to develop in the near future. The effectiveness of the systems currently available on the market will depend on the exact purpose and environment that you plan to use them for. Current systems typically have a height range of around 2.5-3 meters monitoring an area in the region of 1.5 x2.5m and so may not be suitable for certain sites.


Another concern is the ability of the analysis software to identify different types of object. For example, anti-tailgating systems that use TOF technology may not be able to distinguish between people pulling large luggage items through a monitored area and people being followed by a genuine intruder. Moreover, the dimensions and the objects of the environment for which the cameras are used will influence not only their effectiveness but how they are installed.


For this reason it will be essential for anyone considering this technology to consult with an experienced systems integrator to decide whether the technology is the correct choice for their business and how it should be integrated into their existing security system.


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