Video surveillance is a dynamic market, constantly growing and changing. Currently, we're observing a transition from analog to digital solutions. Benefits of that shift are obvious for key players on the market. But what are the benefits for installers and end users? Let me explain; I'll focus on the core of PC-based CCTV systems, because these systems offer the most benefits for the installer and for end users.
PC-Based CCTV Systems
These are applications that manage, record, and transmit video streams. Take the Net Station IP—based Network Video Surveillance System as an example. Most advanced systems that are available on today's market consist of two modules. The first of these is an application module, which has to be installed on a server that meets the following standards requirements:
- Intel processor (Pentium 4 3.0 Ghz (HT) or higher/Pentium D 2.8 Ghz or higher)
- Main board based on Intel chipset (models from i845 and higher)
- Min 512MB of RAM
- 85MB of free hard disk space for software
- Free hard disk space for storing video archives (min. 40GB)
- Microsoft WindowsXP Professional SP2 OS
Cameras are connected to the server through a Local Area Network (LAN). If there are both network and analog cameras connected to this computer through frame-grabbing boards, the system's considered to be a hybrid. Hybrid systems are common for applications that were sustainably developed to manage the work of frame-grabbing boards. If there are only network cameras, then the system is considered to be a fully digital one.
The second module is usually called a client application. Client applications are programs designed to allow users to connect remotely, using a network or UMTS/GSM/GPRS conection in conjunction with the server application. Systems that use both of these modules are either Network Video Recorders (NVRs), or—if they combine network and analog cameras—Hybrid Network Video Recorders (HNVRs).
Mature client applications offer the opportunity to store archives remotely, and in many locations. Clients can be installed on PCs, laptops, pocket PCs, or even PDAs and mobile phones. Archived storage would obviously be very limited in that last case.
On one PC, you can install many different client applications. The end user, being of primary importance, gets the most benefit from these systems. For example, many CCTV installations can be viewed remotely from one computer—such as a laptop—while the data is stored on another one (server). For safety reasons, and to avoid loss, archived data can be stored remotely on many sites, such as on the server site as well as on the clients' sites.
Megapixel cameras produce large amount of data, which is problem when transmitted through low bandwith media like UMTS, GSM, or GPRS; they also consume a lot of hard drive space. As a way to combat the disk space problem, the most advanced surveillance systems offer an option to record movement only. These higher-end systems also use special compression formats.
The data is compressed using one of two types of frames:
- Key frames—large frames that are viewed periodicaly; and
- Motion compensated frames—frames that make use of the difference between the current frame being processed and a previous frame of video
Motion compressed frames ensure that informaton which doesn't change, e.g. a static background, isn't transmitted repeatedly. Different codec can be selected for viewing, for recording, to transmit video, and can be used for each camera separately.
The end users benefit from longer periods of archival storage without the need to increase the size of their hard drives, plus they'll enjoy exceptional quality of live video on their mobile phones. For installers, the most important thing is that the system cooperates with a wide range of cameras available by today's leading manufacturers.
Capacity to Act and React
Official government statistics report that security guards pick up approximately 4% of events as they occur. If a security guard's on his post and being alerted to events in real-time, he's picking up closer to 100% of this activity. Therefore, the leading CCTV system has to be capable of indicating alerts and react.
Alerts can be activated by motion detection in particular areas on each camera separately; this can be accomplished through sound detection or by closing electrical circuits that are connected to system inputs, i.e. integration with access control. If alerted, the system can set outputs such as lights, sending alerts via e-mail, adding bookmarks to archives, or by connecting with client applications.
Triggering tasks may be dependent on assigned time bars in the system's scheduling interface. This may also be dependent on input activity, or integration with access control. If a system's set to record only during movement, options for image buffering and alerts that are based upon sound detection ensure that the entire event will be recorded.
The system's archives are searchable according to each camera time bar; you can also search by movement in targeted areas. For example, an item disapears. The user flags the area where the object's located, in the system's archives. The archives will be displayed until system detects motion in the targeted area.
Recorded events that are signed by a watermark that's specific to a system's digital dongle, and its licence number, is admissible as evidence in a court of law. This, in many cases, makes the surveillance system practically independent on the guards' activity. Integration with access control and a scheduler guarantees that the system will act only when it should, providing a secure environment for people and enhancing the safety of the facility.
User Identity and Permissions
Users of the system are categorized. Administrators may posess all rights, whereas the utser may posses only the right to log in to the system. Keep in mind that any user or administrative permissions on the system are configurable, as well.