The real truth about megapixels & HD

Learn more and bust through the myths

Megapixels, high-definition, aspect ratios, H.264, compression algorithms, lines of resolution, storage-it's enough to make a person's head spin. Coupled with all the other terminology and technology you need to learn to properly specify a video/IP/CCTV installation and you may feel like throwing in the towel.

That won't be necessary if you have an open mind and a willingness to learn. In fact, the recent mantra at the largest security show of the year, ISC West, was a battle cry by exhibitors who realize that this is the time when the systems integrators need their assistance big time-in the way of education, white papers, specifications and training to get their arms around it all.

We went to manufacturers and posed the following question: "what are one to two important distinctions integrators should know about megapixels and HD?" Here's what they said:

Sara Scroggins-Product Marketing Manager-Pelco (Schneider Electric), Clovis, Calif.

"Generally speaking, "high def" or HD imaging is considered to be video that has 1 million pixels-1 megapixel or 1MP-or more, but really can be anything above Standard Definition (SD). More pixels mean more clarity and the more detail within a given scene adds to the ability to identify people and other items of importance. For example, the ability to identify vehicle license plates could prove especially beneficial in certain situations.

HD gives customers more detail in order to digitally zoom in on video after footage has been taken while maintaining the ability to have clear images. This is possible without significantly degrading the image clarity as in the case of SD. The higher the resolution, the greater the detail you can achieve with digital zoom.

When we use the term HD imaging, what we are referring to are actually standards used within television broadcasting. Megapixel simply describes the total resolution of the capture system and has more latitude with regard to transmission, frame-rate and other specifications one might find in the strict definition of HD.

HD serves as a good definition in that it not only provides a resolution requirement but it also provides information regarding the frame rate and aspect ratios; whereas the term megapixel, which we also use in the security industry, simply describes the resolution size. So, in actuality you can have mixtures of both, where you may have megapixel resolution and HD, but when we talk about megapixel it is referring to the horizontal and vertical resolution."

Ed Thompson-Chief Technology Officer-DVTel Inc.-Ridgefield Park, N.J.

"It's important for systems integrators to know that generally all HD cameras qualify as megapixel cameras, however not all megapixel cameras support the HD standards. HD is standards based technology developed for motion pictures and HD broadcast while megapixel cameras only need to support more than 1 million pixels to qualify as an MP camera. The HD standard specifies the aspect ratio to be 16:9 wide screen vs. 4:3 used in legacy SD and megapixel cameras as well as color reproduction and encoding quality.

The advantage of HD is wide-screen capture, or wider field of view. This is a significant enhancement for numerous surveillance applications, because the typical camera captures a lot of sky and ceiling. With megapixel cameras, these images only get wider and wider, so incorporating HD standards in a megapixel camera helps to offset that fundamental issue.

Mark S. Wilson-Vice President, Marketing- Infinova, Monmouth Junction, N.J.

"Today, more and more end-users are asking for megapixel cameras and wanting H.264 compression. The verticals leading the charge into using megapixel and HD cameras are transportation hubs (especially on concourses), warehouses, all types of lobbies and other high-incident locales. Often, though, they do not realize the impact this will have on their systems. Megapixel cameras, including HD, have more than 1,000,000 pixels compared with analog cameras which have less than 400,000 pixels. There are three important factors to remember when considering the use of HD megapixel cameras:

1- H.264, a better compression technology, requires less bandwidth and storage capacity. That's good.
2- H. 264 requires more processing power. That's not so good.
3- Since H.264 has a higher resolution, it requires a higher resolution display. That's not a big issue unless you don't follow through.

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