| Migrating from analogue to HD surveillance solutions |
Globally, the video surveillance market has been slow to move beyond its analogue origins. Many analogue technologies or first generation network video management systems installed in the last decade are now aging, becoming less reliable and unable to deliver the quality and coverage most security professionals demand. Increasing video quality using these older solutions requires an unmanageably large number of surveillance cameras and results in marginal forensic detail, making successful investigations difficult. As a result, we are now seeing a push beyond analogue into the world of high definition (HD) as security professionals begin to look for better video and greater resolution to lead to more successful investigations and higher rates of conviction.
Network surveillance and HD technology – the way forward
A network approach to surveillance, including high definition IP cameras, has proven to be the best way to deliver the extra resolution needed for improved video quality and overall security. HD technology can enhance security and reduce investigation times by capturing video that provides rapid, actionable evidence in place of the blurry, low quality images to which the industry was previously accustomed to.
In this article Rick Ramsay, Product Manager of Avigilon, describes five key design considerations to help security professionals successfully migrate or upgrade their surveillance systems to high definition as cost-effectively as possible.
1 - Address the core of the surveillance system First
Taking the POT approach to system design, security professionals can significantly reduce overall surveillance camera count while still achieving the best level of detail |
Many organisations begin their upgrade initiative by replacing their cameras, but this is not necessarily the right place to start. Conventional systems that archive video from VGA cameras compromise quality because excessive compression eliminates detail, meaning that security professionals cannot recover visually lossless video.
Instead of trying to replace existing surveillance cameras, system designers should first find a compression and transmission software “engines” that maximizes the performance of existing VGA cameras and lowers costs. This approach, in combination with analogue to digital encoders, allows system designers to preserve assets while improving video quality – without re-cabling new cameras. Complement the existing camera network by designing a hybrid system complete with HD cameras at high traffic areas and protect critical views to the extent budget allows. By doing so, system designers can scale and add HD capability over time.
| Image showing the different levels of coverage in specific pixel resolutions |
|
|
2 - Define the video quality required using “Pixels on Target”
With megapixel surveillance cameras, users can define the video quality required to capture the desired forensic detail by using the new industry “pixels on target” (POT) metric. Commercial, off-the-shelf megapixel cameras are available today in one to 16 megapixels, allowing designers to build a fit-to-purpose system. A one megapixel camera delivers 327 percent more pixels than VGA while a sixteen megapixel camera delivers over 5000 percent more! POT is calculated by dividing the width of the scene covered by the horizontal resolution of the camera. A 1000 pixel wide camera covering 10 feet provides a POT of 100 pixels per foot.
To positively identify a human face, a POT of 40 pixels per foot is required. A single 16 megapixel camera can cover scenes up to 120 feet wide and capture 40 pixels per foot. In comparison, to achieve the same level of detail would require 50 or more conventional surveillance cameras. Taking the POT approach to system design, security professionals can significantly reduce overall camera count while still achieving the best level of detail required for each situation, thereby lowering costs while enhancing overall surveillance. And, the improved video detail available will result in a higher percentage of successful investigations and speed deployment for first responders.
3 - Reduce bandwidth requirements for video transmission
Perhaps the most crucial task for an HD surveillance system is to manage the transmission and display of visual information on monitoring workstations and shared remotely by associated decision makers or other agencies. The benefit of the additional detail provided by HD can be wasted by the inability of the system to transmit, process, or manage it properly.
Intelligent HD platforms use data management software to manage transmission and display using a progressive compression method. An HD data file is a deep three-dimensional stream that provides high forensic video value, archived and processed at the edge of a network. However, an investigator monitoring or calling up information will only view a portion of the file at any given time. By sending only the requested pixels and not the entire data stream, the monitor workstation does not become overwhelmed with processing unnecessary pixels or data. This design produces immediate savings in bandwidth for transmission and requires less processing power at the workstation level.
View larger image Blurry image of stadium | View larger image Clear image of stadium |
4 - Improve video storage and retrieval
More pixels, more evidence, and more detail all result in the need for more storage. An effective video storage management system offers advanced tools that enable security professionals to manage available storage, including per camera data aging, maximum retention time, and scheduled online backups, also taking advantage of network design. Intelligent data aging allows organizations to retain recent footage at the original highest frame rate and then after a set time, store footage trimmed to half the original frame rate and at a further point in time, at one quarter the original frame rate for improved storage efficiency. System designers should look for a video storage management system that can set this standard on a camera-by-camera basis to achieve precise control of data quality and retention periods for each camera.
Once a robust, underlying data gathering, transmission, and management system is in place, the real worth of a HD digital surveillance system becomes clear |
5 - Take advantage of real time video analytics
Once a robust, underlying data gathering, transmission, and management system is in place, the real worth of an HD digital surveillance system becomes clear: it can be digitally monitored to immediately and irrefutably detect unusual situations and associated detail, and can even perform accurate facial detail validation. Advanced video surveillance software can more effectively monitor real-time surveillance information gathered by cameras. When the software detects an event, it can alarm and alert security professionals for immediate investigation of the situation. Since HD video detail is far greater, judgments are more rapid and accurate; resulting in potentially reduced and resolved crises.
If the megapixel surveillance camera is equivalent to the eye, then recording, transmitting, storing, and monitoring solutions can be considered the brains behind an HD surveillance system. By specifying a software “engine” that can handle the transmission, recording, and analytics, security professionals can incrementally migrate from analogue to digital HD systems more easily.
| Rick Ramsay Product Manager Avigilon |