What's meant by 'edge-based' surveillance, and what benefits can it deliver? Read on to find out.

What exactly is meant by 'the edge'?

'The edge' is an IT infrastructure phrase used to describe a situation where data is processed and/or stored at the periphery of a network rather than centrally. In a surveillance context, the terminology has evolved to focus on capabilities at the camera end rather than at the 'head end,' such as the NVR or video management system (VMS) server. It can also refer to any device used as a potential data source as part of the system, for instance, sensors or access control readers.

What surveillance functions can be done at the edge?

Several essential functions can now be carried out at the camera end. However, the two most notable relate to analytics and storage.

Why should I consider edge-based analytics?

Most VMS systems available today will offer built-in analytics or integrate with third-party analytics software or a mixture of both – as with Synergy. For example, algorithms are applied to footage to count people, detect when specific objects or people are present, set virtual tripwires, and detect movement hotspots.

But transmitting the volume and quality of video footage needed for effective analytics from camera to VMS can take up a lot of bandwidth. Using analytics-enabled cameras can help with this by:

  • Only transmitting footage when a specific event is detected e.g. a virtual tripwire is triggered; or
  • Recording and transmitting at a lower resolution as standard, only switching to a higher resolution when a specific event is detected.

Moving analytical processing to the edge makes it possible to reduce server and network infrastructure requirements and, therefore, potential maintenance costs.

Are there any important considerations with edge-based analytics?

A combination of server-based and camera-based analytics is often preferable. Especially if advanced analytics algorithms that harness deep learning or artificial intelligence are required, as these can demand processing power that isn't yet suited to in-camera analytics.

It is also essential to think about recording environments. For example, adverse conditions that impact lighting and camera motion may cause some cameras with analytics capabilities to generate false alerts or miss events. In these situations, it may be advisable to use hazardous-area cameras with analytic capabilities, such as cameras designed for demanding environments or choose a server-based solution.

Why should I consider edge-based storage?

Edge-based recording using IP cameras has been around for some time. It gives the ability to record directly to the camera's SD card rather than centrally. However, the most valuable – and most common – application is as a redundancy measure for IP-based surveillance solutions.

In the event of a network outage, writing to a camera's SD card ensures no data is lost. H.265 compression capabilities coupled with advances in technology also mean more data can be stored on SD cards than was previously possible.

If cameras only record to the SD card and do so all the time, this can still mean cards have to be replaced with great frequency. For large networks with significant camera counts, this can get very expensive very quickly.

Is there an alternative to relying on the SD card as an edge-based storage redundancy measure?

Solutions like Synectics Intelligent Edge Recording (SIER) can help extend camera SD card life by reducing write cycles. SIER mitigates the risk of footage loss by using the in-built camera memory to store a cache of video footage. The SD card is only used if the Synectics IP camera cannot connect to networked storage hardware. Once the network is available, Synergy's backfilling functionality automatically retrieves the data and restores it to the server once available.

As well as guaranteeing uninterrupted footage access, SIER also avoids potential issues such as SD card malfunction or data loss due to overwriting. It also reduces the maintenance burden and cost of replacement SD cards, making it a cost-effective solution.