Knowing When to Use IP
You checked the latest RFP, and a local government organization—let's say a school district—wants to install surveillance cameras in its facilities, and they're accepting proposals that specify either IP cameras or analog cameras. Which should you use?
The answer really depends on several things.
Notably, you need to know:
- How many cameras are required
- What image quality is needed
- Where the cameras need to be
These are the key factors in determining whether an IP solution is right for your customer.
Modern structures are often strung with a reasonably high quantity and quality of CAT-5 cable (or even fiber-optic) in order to support the IT requirements of business taking place inside of them. And much of the time, the amount of cable in place is far greater than the customer's IT department ever anticipated needing for itself.
So you may be able to piggyback off of this infrastructure to install IP cameras without having to run BNC cables. The more cameras you're installing in a situation like this, the more attractive IP surveillance becomes. It's simple enough; IP cameras are more expensive than analog cameras, but the costs of supplying and running hundreds of yards of cable are significant. Aside from the cost of materials, you have to include the cost of labor in your bid. If there are enough cameras involved in a project, this can actually make IP cameras cheaper than analog units.
Another point to consider is the image definition needed to accomplish your customer's stated objectives. If the customer has asked for systems capable of recording recognizable footage of a specific individual, analog cameras may not be the answer. At 540 TV lines of resolution, even a high-end analog surveillance camera offers no more than about 800 x 500 pixels per frame.
That's significant because the ability to recognize fine detail, like facial features or license plates, requires enough pixel density to catch those details. To resolve a license plate well enough to read it, you'll need at around 40 pixels to cover the plate. Facial details are even smaller. With an 800 x 500 viewing window, you can expect that level of pixel density in an area about 20 feet wide.
Pixel density at or above 40 per objective foot is hard to get at long ranges unless you use a lens with a long focal length (and hence, a narrow field of view). Since a narrower field of view means less light coming through the lens, you'll also have to contend with reduced performance in low light compared to the same camera with a shorter lens.
An ordinary IP camera actually won't help with this challenge, but the highest performance in the IP surveillance world is offered by megapixel cameras. These devices offer image definition at 1200 x 1080 pixels or greater—about three times what an analog camera provides—and hence they allow your system to resolve much finer details.
The last question, where you're putting these cameras, is partly a function of the camera's capabilities. The further away from the objective, the better the camera has to be to provide a designated standard of image quality. But sometimes a better camera, even a megapixel camera with a telephoto lens, simply won't be able to resolve a clear image unless you get it closer to the action. The problem is that it can be really tricky to string transmission cables. This is a challenge that faces integrators using both analog and IP cameras, but IP-based products have an edge because some are capable of transmitting a signal over WIFI. There's a premium on camera units with this functionality . . . but when the alternative is to have no camera in a key location that premium is worth the money.
