In this, the first of several educational articles, the Detektor Security Academy, sponsored by Axis Communications, will explain how to get an optimal image quality and a cost-effective video surveillance solution for different video surveillance applications.
Image Quality - a matter of usability
– how to get the best, and most cost-effective video surveillance results
In recent years megapixel cameras have often been mentioned as the key to solve the problem of poor image quality in video surveillance systems. That is not really true. There are many factors to take into consideration in order to obtain an optimal image quality. First of all the term “image quality” needs to be defined. The usability, for the end user, is probably the best reference when measuring image quality.
By Johan Paulsson,
Global recession notwithstanding, video surveillance has been the fastest-growing sector in the security industry for nearly a decade, with both private and governmental organisations around the world investing large sums of money.
Several factors drive the explosive growth, and they hinge just as often on cost controls and cost-effective management as they do on the public need for a greater sense of safety in the post-9/11 world. A far cry from the days of closed analogue CCTV systems, today’s digital video surveillance cameras operate over flexible, easily scalable IP networks that authorised users can access in real time from just about anywhere. Using industry-standard, reliable, vendor-independent technology, they are easy and cost-effective to integrate. In today’s network video systems, intelligence resides throughout the system, not least at “the edge” (i.e. in the camera or video encoder) itself, which enables it to determine when and where to send video, at what frame rate and resolution, and when to alert a specific operator for monitoring and/or response. The result: surveillance systems that are cost-effective, future-proof and adaptable to the evolving needs of the installations they serve.
It is, of course, the digital revolution that makes this all possible. And, just as newer, more powerful, more feature-loaded cameras, laptops and mobile phones constantly tempt today’s consumer, the network video market is regularly bombarded with new product offerings that promise ever-greater benefits for the user.
Only by carefully analysing your video surveillance goals can you define the right requirements for your installation.
Taking the user-centric view
Image quality is often foremost among the touted benefits. Just like their counterparts in the consumer goods market, many of today’s surveillance camera manufacturers are in a race to deliver product with higher and higher image resolution. The supposition is: the higher the number, the sharper the image and the greater the satisfaction for the end-user.
What this approach roundly ignores is the actual needs of the application. Do you want overview surveillance, or detailed images? Will video be viewed live, or logged and stored for months – or even years? IP networks must be able to handle the traffic load of high-resolution video, and storage requirements can quickly expand to terabytes, so these are critical considerations.
Six steps
There are six simple, sequential steps to creating a successful video surveillance solution for the end-user. The first two should precede any equipment, software or systems decisions. The third and fourth should fulfill the decisions made, and the last two take place during the commissioning of the customer’s video surveillance system. The consultant’s or integrator’s professional expertise will determine if everything is done right, and is a valuable safeguard for a cost-effective life-cycle video surveillance investment.
It all starts with a thorough analysis of actual user needs.
1. Goal definition
Only by carefully analysing your video surveillance goals can you define the right requirements for your installation.Before selecting equipment or systems, the first step is to define how the results will be used. Do you need a general overview of an area or people’s movements, or high detail (facial- or license plate recognition, for example)? Complete installations often include both, so it is important to consider each in its own context to achieve the most effective solution.
No single type of camera is optimal for every application. The best solution often combines HDTV network cameras, megapixel network cameras and standard resolution network cameras that are optimised for different needs – such as pan/tilt/zoom, extreme light sensitivity or cost-efficiency.
To optimise an installation you must also consider the whole system, not just the cameras, because factors like video management software, network capacity and video storage requirements often set limits for image resolution and frame rate.
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