How many times have you seen an image of a suspected criminal flash across your television screen along with the question, "Have you seen this man?" Perhaps your response, verbalized or not, was "That was a man?"
Why does this happen?
Surveillance Cameras and Recorders are highly specialized devices. As such, they accomplish very specific tasks. In the above scenario, it is clear that a camera designed for one purpose was used in an area that required a camera designed for a different purpose. A competent system designer can help you avoid the pitfalls by matching the right equipment with your purpose.
In any system, there are generally only TWO considerations which govern the decision of what equipment to install. The two factors are simply: Observation and Identification. A system designer must balance each component in the system so that the goal of observing or identifying can be acomplished most efficiently and economically.
Identifying an individual on a video recording requires a varying amount of detail. For example, identifying a person known to you is easier than an unknown person. Some might think that simply installing a "higher resolution" camera will do the trick, but other factors go in to capturing an image of sufficient quality to identify. Having the proper lighting conditions, lenses, and even the correct recorder can all come into play.
Let's look at lighting, for instance. Perhaps you want to capture pictures of individuals entering your retail establishment - clearly they are unknown people. We'll assume that they enter the doorway between the hours of 11:00 a.m. and 11:00 p.m. What are your lighting conditions? Well, a good amount of outdoor light is present from 11:00 a.m until sunset. What if the door is facing west? That means that at sunset a very bright light is directly behind people as they enter. After sunset, only interior light is present at the entryway. And finally, what if there wre a break-in after hours when no lights are on in that part of the building?
As you can see, simply selecting a camera with "higher resolution" is really a blind guess as to what image you'll end up with. In fact, even with the highest resolution cameras, you may be unable to see any image at all in certain lighting conditions!
Not all cameras need to be defined as "identification" cameras. For instance, in a large parking lot, installing cameras sufficient to see a detailed image of every person in the lot at all times can become very costly. More often than not a camera that simply observes - for example, the person in the green shirt and blue jeans that got into the red pickup truck - may be all that is needed. Why? If the truck must come through a single entry or exit point, "identification" can be made there - perhaps getting an image of the person's face as they pay the parking fee, or capturing the license plate number on the truck.
An experienced system designer will also look at the overall traffic flow of any location, and then fits each specialized camera to each very specific task to ensure you get the most cost-effective solution to your surveillance needs.