[Editor's Note: This is the first in a series of three articles addressing the growing technology of megapixel video surveillance cameras. Upcoming installments (to be published on SecurityInfoWatch.com during March 2007) will cover topics of digital zoom versus mechanical pan/tilt/zoom, and the relationship between megapixel cameras and storage/bandwidth needs.]

Megapixel Surveillance Cameras: Worth the Price?

Why are so many end users switching to megapixel technology, or at least examining this technology at tradeshows and in project bids? The main reason is price. That probably sounds confusing since the conventional wisdom is that a reliable, industrial-quality megapixel network surveillance camera is three or even four times more expensive than comparable low resolution (4CIF) security cameras. How can the megapixel camera be cheaper?

Video Surveillance Goals

Before we take up price, let's first discuss why an end user would even consider megapixel? This is the most important question because in some instances megapixel cameras may not be appropriate. Before you look at any camera or NVR/DVR combination you have to initially define the goals for your video system. For simplicity, we narrow the security goals down to three categories:

1. General Surveillance: These are applications; often live viewing, where you don't need detail on recorded video. For instance, you may be watching a road and looking for traffic jams but do not need to read license plates. Or you may be looking to see what a crowd is doing but do not need to recognize faces. You may simply want to detect when someone is in a restricted area so you can respond immediately.

2. Forensic: These are applications where you need to see, record, and recognize images like license plates and faces, so you can go back "after the fact" and determine exactly what happened.

3. High Detail: Applications where you need to read a license plate but also read the model of the car. In a retail or banking context, you need to clearly see the customer's and employee's faces as well as identify the currency in their hands.

By assigning a category to your application you are, in fact, defining the resolution requirements. With older surveillance technology, resolution was defined by its TVL (television lines, a.k.a. total video lines). Over the last few years the market has evolved to defining resolution by the total number of pixels. This is more objective when comparing products that have different resolutions. So, when an image is 640 x 480, that is actually 640 (horizontal or columns) pixels x 480 (vertical or rows) pixels, for a total of 307,200 pixels, or approximately 0.31 of a megapixel (million pixels).