Pandith Jantakahalli of MindTree Ltd provides an overview of what needs to be taken into account when designing a surveillance system – and looks at the pros and cons of analytics and storage at the edge of a system, at the server, or distributed across both.
Security objectives, practical aspects, reliability aspects and costs are the key factors which will impact the architecture that will be chosen for a security system.
Examples of how security objectives determine the solution to be deployed, which in turn impacts the architecture, are listed below.
Prevent or respond to events as they happen. For example, send a security officer when someone jumps a fence, or recognition of the number plate of a car that has been parked in a no parking area.
Deploy video analytics to identify and isolate events of interest.
Complexity of video analytics will dictate where the video analytics will be deployed. For example, high complexity video analytics is usually run on the server as there are not many choices available today for running complex video analytics at the edge.
Providing evidence for only what happened. For example, provide video evidence that a person has stolen a particular asset.
Record only events of interest.
This enables greater flexibility in deciding the architecture. For example, a camera with on-board video analytics and storage can be considered.
Providing evidence for what did NOT happen. For example, provide video evidence that somebody did not slip and fall within the establishment’s premises.
Record on a continuous basis and retain recording for the required duration.
This limits the choice of architecture as the camera will not have the required storage capacity especially if the video feeds needs to stored for long duration (more than six months).
Providing evidence that is acceptable in the court of law.
Careful camera placement, appropriate selection of resolution and frame rate for recording.
Storing videos with high frame rate (more than 15 fps) and resolution D1 or greater will impact storage capacity to be deployed and hence the architecture. Current option available for storage capacity on the camera is in the range of 500GB.
Need to view video feeds simultaneously at the security control room and remote locations.
Provision for enough bandwidth based on the number of video feeds that need to be viewed, recorded and analysed.
Bandwidth requirements will limit the choice of architecture. For example, if the bandwidth requirement is high, a wireless based networking solution may not be possible.
Examples of how practical aspects determine the solution to be deployed which in turn impacts the architecture are listed below:
Need to protect investments in deployed solutions. For example, an establishment already has invested in analogue cameras and DVRs.
It may be more appropriate to use video encoder to convert analogue video feeds into IP instead of replacing the cameras.
It may not be possible to embed analytics on the existing cameras. Adding storage at the edge may be limited to the storage capacity available on the encoder.
Time taken to detect a security breach or incident.
Retain recorded video based on time taken to detect previous incidents.
Storage requirements will limit the choice of architecture.
Business needs may dictate the architecture. For example, a bank may need to place multiple cameras in each of its branches/ATMs across different locations in a city.
Provide as much information and control at the branch, while allowing for centralized / remote monitoring.
A distributed architecture with centralised monitoring may be the most appropriate architecture.
Area that needs to be monitored is spread over a large area and it is not possible to have Ethernet / Fibre networks.
Explore wireless alternatives.
Architecture will get driven by bandwidth constraints.
While all security systems must operate at a very high level of reliability, expectations on how much downtime can be tolerated will impact the architecture decision as well:
Availability of budgets to meet the security objectives is a crucial element in determining the architecture: