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In the last few years, demand for the digital megapixel cameras has exploded. The trend started in the late 1990s with consumer digital still cameras and started to gain traction in the surveillance industry in 2002 with megapixel IP network cameras. Today, millions of consumer digital still cameras and tens of thousands of meapixel network cameras are being used every day.

Megapixel IP Cameras' image quality advantage

The picture quality advantages of megapixel network cameras benefited end-users in a couple of ways. In some applications, a mega-pixel network camera could cover the same area as a CCTV camera with an im-proved level of picture quality so you could actually identify people. We are all too familiar with images captured by CCTV systems where the quality was so poor little could be learned and often no positive identification possible. Megapixel network cameras solved this major disadvantage..

Standard CCTV Image

Megapixel CCTV Image

For other applications, megapixel meant covering a much wider area than CCTV cameras. Comparing apples-to-apples, a one megapixel network cameracan cover more than four times the area of a CCTV camera with the same resolution. This means you can replace four CCTV cameras with a single megpixel camera, or 10 CCTV cameras with one 3.1 megapixel camera. End-users embraced this new power and efficiency immediately and the migration from CCTV to megapixel network cameras has predictably accelerated.

Misconceptions about megapixel cameras

True or False? Megapixel network cameras can be less costly than CCTV cameras?

TRUE! There have been misrepresentations that megapixel network cameras cost more than CCTV cameras.The initial cost of a professional quality megapixel network camera may be higher than a CCTV camera.However, in a large majority of applications, the total cost of installing a system using megapixel network cameras is substantially lower, sometimes as much as 50% lower. If you are considering using a megapixel network cameras as a one-for-one replacement of a CCTV camera, and there is no established IP network mega-pixel may be more expensive than CCTV. But the only reason to ever consider swapping one-for-one is because the CCTV camera cannot deliver the image quality you need. Put another way, a tricycle is indeed cheaper than a Ferrair, but if you need to go 200 mph, try doing that on that nice cheap tricycle.

True or False? Megapixel network cameras use more bandwidth and storage than CCTV cameras.

False! Of course megapixel images are larger than CCTV images, but once again this is not an accurate or helpful comparison. If you want to replace CCTV cameras one-for-one with megapixel cameras, it is because the CCTV camera can not deliver the image quality your demand, Period! A more instructive and fair analysis is to compare the file sizes of four (4) 704 x 482 CCTV cameras against a single 1280 x 1024 megapixel image. If all cameras are configured the same, with the same compression, and are looking at the same scene at the same time you will find that a magapixel network camera actually uses less bandwidth and storage than the CCTV cameras combined. See below for an example.

4 Standard CCTV Cameras 704 x 482

1 Megapixel CCTV Camera 1280 x 1024

False! There is no delicate way to state it: this statement is absolutely, unequivocally false, false, false, false, false!

The area you can cover with reasonable detail (enough to recognize a face or license plate) does not depend on the lens, it depends on the number of pixels covering the scene. The best CCTV cameras have, at most, 704 x 480 pixels. As a general rule, 30 pixels/foot lets you recognize a face or read a license plate. So, the best CCTV camera can cover an area of 23 feet wide (704/30) and 16 feet high (640/30) for a total of 368 feet squared. Knowing that, you would need to select a lens that gives you, at most, a 23' wide field of view to get enough detail. Putting a wider lens on the camera will simply blur the image and putting a telephoto lens on the camera will get you a sharper picture but a much smaller coverage area. Alternatively, a 1280 x 1024 megapixel camera lets you cover a 43' x 34' area or 1462 feet squared (4x the coverage of the CCTV camera). A 3.1 megapixel camera, at 2048 x 1536, can cover 3450 feet squared or almost 10x the coverage of the CCTV camera. The lens simply determines how far away you want that level of detail. A wide angle lens can get the detail very close to the camera and a telephone lens can get the detail at a great distance from the camera, but neither gets you megapixel quality and area of coverage.

Whats the right technology for you?

So, how do you choose the right components to make sure you never miss a thing?

First, determine how wide an area you want to cover. For instance, if you want to cover a 10,000 square foot parking lot with license plate and/or facial detail. your choices are: 28 CCTV cameras, seven 1.3 megapixel cameras, or three 3.1 megapixel cameras.

Next, determine the camera to object distance. This is critical for selecting the right lens. Remember, the lens does not increase the resolution of the camera, it simply defines where you are focusing. Once you select the right focal length of the lens make sure the lens matches the camera quality. A lens does not increase the resolution of a camera but the wrong lens can absolutely hurt the resolution of the camera so while a plastic lens may suffice for a CCTV camera, a megapixel camera needs a mega-pixel quality lens.

Replacing several low-res cameras with a single multi-megapixel IQeye IP camera improves the viewing experience by eliminating the need for multiple monitors and complex, thumbnail multi-view screens.

The first step is to determine the type of video surveillance you want to do. For simplicity, we can narrow it down to three categories.

1.)General Surveillance. These are applications where you don’t need detail for live or recorded video. For instance, you may be watching a road and looking for traffic jams, but don’t need to read license plates. You may be looking to see what a crowd is doing, but don’t need to recognize faces. Or, you simply want to detect when someone is in a restricted area so you can respond immediately. Typical Applications – Traffic, City Centers, Arenas/Stadiums, Military, Shopping Malls

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 and identify perpetrators. Typical Applications – Schools, Airports, Retail, Banking, Tolls/Parking Lots, Casinos, Commercial/Industrial

3.)High Detail. These are applications where you want to be able to see a great deal of details, such as not just read a license plate, but also the model of the car. In a retail or banking context, you might want to clearly see the customer’s and employee’s faces, as well as identify the currency in their hands. Typical Applications– Cash Counting Rooms, Casino tables, Machine Vision

Determining Coverage

For this parking lot, let’s say you want forensic video surveillance. You want to be able to identify a perpetrator. Our next step is to determine what kind of coverage that requires. Coverage is the amount of area a camera “sees.” To determine coverage, you need to consider the appropriate pixels/foot for the desired surveillance quality. The following chart shows the pixels/foot required for good coverage for each category of surveillance.

Now let’s apply this to our parking lot. Let’s say you want to cover a parking lot that is 100 feet wide with forensic detail. When we do the math we find 100 feet x 40 pixels/foot = 4,000 pixels. This is the resolution you would need to be able to recognize detail like license plates and faces.

The next step is to determine what resolution cameras you want to use. You determine this by dividing the number of pixels you need (4,000) by the number of horizontal (columns) of pixels provided by your camera. In a 640 x 480 camera, the first number is the horizontal, the second number is the vertical.

Here are all the ways you could get the resolution for forensic detail in a 100-foot wide parking lot. We round up in cases when there’s a fraction of a camera. (There’s a handy calculator at www.BevanSecurity.com/PPFCalc.html

Note that just two 3-megapixel cameras can cover the same area as seven standard 640 x 480 cameras. This becomes more remarkable when you consider cost.

If we use 2008 prices taken from online sources, a high quality camera made by an established manufacturer that delivers a 640 x 480 image has an MSRP of about $350 (all dollars figures are USD). A high quality camera made by an established manufacturer that can deliver a 2048 x 1536 image has an MSRP of about $1249. In the following price comparison tables, we’ve priced the corresponding “extras” similarly for both camera types.

As you can see, the megapixel camera option is actually the lower cost solution in this case. While the individual cameras cost more, they also cover more area and in situations like this can save you money.

What about storage costs? Well, all things kept the same in terms of compression, two images from 3-megapixel cameras will typically take up less storage than seven images from the seven 640 x 480 cameras.