As video camera and storage prices continue to decline, the scale of video surveillance systems grows. Not so long ago, a system with hundreds of cameras was considered significant. Now, systems containing thousands of cameras are not a rare case. Many of them (and most of the largest ones) are distributed across multiple sites. So, organizations increasingly face the task of unifying dispersed surveillance installations.
The Reason for Unification
A reasonable question is, why unify? Why not let the systems at different facilities work independently, employing local operators to monitor and manage each one? There may be various causes for unification, and here are some of the most common examples:
· Certain businesses, such as some retail chains, have multiple small to mid-size facilities with a few cameras, and having an operator at each facility is economically impractical. Moreover, some facilities, such as cell towers, cannot allocate space for the operator.
· Many tasks, e.g., incident investigations or business process monitoring, are more appropriate to handle at the level of the organization, not a single facility.
· Critical facilities may require centralized command and control and local monitoring rooms for maximum security.
Unification Tasks
What capabilities should a unified video surveillance system deliver to ensure efficient monitoring and swift response to alarms? Remote viewing of live and recorded videos (from one site at a time) is only an essential function that doesn’t require unification. Different cameras in various locations must be viewed simultaneously when setting up monitoring centers.
The same applies to alarms: an operator must be able to receive alarm events and related videos from multiple sites in a synchronized manner without the need to switch. An advanced feature of unified systems is multilevel alarm management used when establishing a hierarchical structure of monitoring centers, for instance, for state-wide gas stations or retail chains. This functionality provides such capabilities as escalating critical alarms to a higher level and reports on alarm processing to monitor the quality of operators’ work.
Real-time health monitoring that alerts of any hardware, software, or network issues is crucial for large installations, especially when there is no constant staff presence at every facility (like cell towers). Centralized reporting based on system health parameters and video analytics data (alarms, visitor count, queue lengths, etc.) is essential for optimizing business processes, as well as the operation and maintenance of the system itself. Finally, when multiple users work with different cameras, reports, and other functionalities, it is imperative to have flexible user rights management and store individual user settings.
Let’s consider how several distributed video surveillance systems can be technically unified.
Technical Implementation — Cloud
The approaches to deploying video surveillance solutions may be split into two major categories: on-premises systems and cloud-based systems or video surveillance as a service (VSaaS). VSaaS systems are distributed and unified by nature. Video and metadata are streamed directly from cameras or via bridge appliances to the cloud, where all the data is processed and stored. No matter where cameras are located, the only requirement is a stable internet connection with sufficient bandwidth. Users connect to the cloud via the internet to view videos, mainly web browsers and mobile apps. Most cloud services provide alarm notifications. Some offer health monitoring that is typically limited to alerting upon losing a video feed. Depending on the provider, VSaaS may also deliver user rights management, video analytics, and reporting.
While cloud-based video surveillance is quite a convenient solution for most SMB and home users and the easiest way to monitor multiple distributed sites, it has significant limitations for enterprise applications. Camera numbers at the sites are limited by upstream internet bandwidth. Health monitoring is usually essential and can hardly help recognize the cause of a failure; it also cannot monitor the complete set of parameters and resource utilization in real-time and does not provide the corresponding reports.
User rights management is not designed to handle hundreds of users with different access levels. Finally, video analytics, even when using advanced technologies like AI, is very limited in customization, as are the reports. It’s also worth noting that many large enterprises impose strict security requirements, implying that video surveillance works over closed-circuit networks, which makes VSaaS not applicable.
Technical Implementation — On-Premises
On-premises video surveillance systems employ servers with installed video management software (VMS) or network video recorders (NVR) that receive, process, and store video and metadata from cameras. Several VMS servers can be joined into a single system with a single database for events, users, settings, etc., in various ways, depending on the VMS developer. For example, each server may have its copy of the database, which can be synchronized with the other server’s peer-to-peer or via a synchronization server. Also, a dedicated server (group of servers) may be allocated to store the database. In any case, a stable network connection between servers is necessary to transmit events and sync databases.
When the VMS servers are in different remote facilities, with no dedicated communication lines between them, all the servers can't operate. Any network issues may cause system malfunctioning, and problems may occur when increasing the number of servers to high values.
A Combined Approach
Is there a solution for unifying large, distributed, on-premises video surveillance systems? Yes, and this is a combined approach. This approach implies that the systems at different facilities are independent and unified, with a single database, local monitoring, etc. A dedicated software suite usually hosted in the monitoring hub handles all the aforementioned unification tasks. It stores user settings, implements user rights management, provides user connections to remote systems, and centrally collects health/alarm monitoring and reporting data. These functionalities may also be orchestrated via a hybrid cloud, combining on-premises servers with a private cloud-based monitoring service.
This approach brings multiple benefits. It offers easy access to any site combined with the security, control, and resource customization of on-premises infrastructure. Various client applications are available to users, including desktop clients with all their advanced features. Any number of users can work with the system using individual GUI settings and in accordance with their access levels. The solution can work over private networks (virtual or physical), while video footage is stored on-premises. This is crucial for organizations with strict security standards. Bandwidth limitations between the sites and the monitoring center and possible network issues do not affect the operation of local systems. Finally, such solutions are primarily developed for enterprise-scale applications. Therefore, they provide a flexible combination of local and central comprehensive monitoring, customizable reporting, advanced alarm handling, and, optionally, specifically designed user interfaces for convenient work with large systems.
The Conclusions
In today’s world, more and more businesses and public institutions take advantage of the unification of distributed video surveillance systems. Central real-time monitoring and investigations are often profitable in ensuring security, operational efficiency, and cost-effectiveness. Increasingly popular cloud-based solutions (VSaaS) offer a convenient way to get many unification benefits. However, a lot of large organizations still prefer on-premises systems that better comply with their security policies and customization requirements. Purpose-built software suites provided by enterprise-level VMS developers and hosted on-premises or in the private cloud help such organizations obtain high-scale video surveillance solutions that meet their needs.
