As in the consumer market, prices for flat-screen monitors for security applications continue to fall dramatically. If CRT monitors haven’t disappeared completely, then that day will come soon. Propose using CRT monitors in an application and see how long it takes your customer to burst out laughing. People just expect flat screens. That CRTs also take up more space and are less energy-efficient only serve to underscore their coming demise.

In the world of flat-screen monitors, LCD monitors appear to have taken the lead over other technologies. Advances in the technology have resulted in monitors that offer improved image quality, truer color reproduction, increased clarity and better contrast — all factors that are crucial in security applications where life-or-death isn’t just a saying.

All LCD monitors, however, are not created equal. For example, do you know the difference between an A-grade and B-grade LCD panel? (B-grade panels use backlighting, rather than LEDs, and may include “used” LCD.)

So what are the criteria for selecting a quality monitor or display? And which, if any, are more crucial than others? For answers to these questions and more, read on.

The ‘Big 3’

While the final decision on monitors and displays will come down to the particulars of the specific situation, there are three major factors that have to be considered. Opinions on the order of importance may vary, says Gary Perlin, director of CCTV products for Tri-Ed /Northern Video Distribution of Rocklin, Calif., but these “big three” should be the first considerations in choosing a monitor or display.

Perhaps surprisingly in a climate where camera megapixels are climbing higher at a dizzying rate, resolution doesn’t play a major role in the selection process. Keep in mind that the top-of-the-line HD monitors available today top out at just 1.3 megapixels for smaller (19-inch or less) monitors and just over 2 megapixels for larger models. The beauty of megapixel cameras is in the digital zoom, which allows the monitor to display a smaller area of the video to be displayed at that 1- to 2-megapixel level.

So if you stop and think about it, says Gary Clinton, vice president of Loves Park, Ill.-based Clinton Electronics, placing resolution lower on the food chain just makes sense.

“Resolution is probably the least important factor since almost all LCDs of similar sizes have the same resolution,” he says. “The most important is contrast ratio. The higher, the better. High contrast ratio makes blacks look blacker, while still allowing you to see into the shadows.”

So just how high should that contrast ratio be? Perlin says 1,000-to-1 is a good standard. Of course, anything higher than that will be better.

Brightness, also known as luminous intensity, is measured in candelas per meter squared or “nits.” A high number is important in any application, but depending on the particular setting, “high” is a relative term, says Rich Morgan, general manager of Pegasus CCTV in St. Matthews, Ky.

“If you’re using a monitor in a low-lighting, security control room situation, then anything above 300 to 400 candelas per meter squared is a waste,” he says. “But if it’s going to be in an office that gets a lot of sunlight, then you may need a more expensive sun-rated monitor with a rating of 1,500 to 2,000.” (To provide a sense of perspective, a standard VGA monitor is usually anywhere from 250 to 450.)

Maintaining a high level of security is the obvious reason brightness — as well as the other two criteria — matters. There also can be a business or financial reason, Clinton says.

“The higher the brightness, the more reserve you have to use for the future,” he says. “As panels get older, they lose brightness, so you can turn it up to compensate as it ages.”

Rounding out this trio of selection criteria is viewing angle. As with the first two criteria, bigger is better. Specifically, the higher the viewing angle, both horizontal and vertical, the better the result.

“In the security world, we rarely sit directly in front of the screen without anyone else looking over our shoulder at the same screen,” Clinton says. “So wide viewing angles are important to see off-axis without any color shifting.”

Often something as simple as the monitor’s stand can make a big difference in a monitor’s viewing angle. If it’s not adjustable, the viewing angle can be greatly decreased. Kickstands, which come standard with some monitors, are notorious for their incapability to adjust angles. Additionally, something as simple as a black-colored base screen and/or anti-glare shield can help reduce glare and improve color rendition.

Refresh Rate

While the contrast, brightness and viewing angle are at the top of the heap, that’s not to say they’re the be-all, end-all when it comes to making informed decisions about monitors or displays. Again, opinions on the order of importance of these additional criteria are up for debate, but their importance is pretty well-accepted.

That said, from a performance standpoint, perhaps the most important of these second-tier factors is refresh rate (also referred to as response time). In this case, a lower number is actually better because a higher refresh rate results in distortion of the video — particularly if there’s fast motion in the scene. Not only does this make it difficult for the person viewing the video, but this kind of lag is no friend to video analytics.

“Response time is critical, especially on the bigger monitors, which can drag behind,” Morgan says. “Without a low response time, it can be like watching a Charlie Chaplin movie.”

According to Perlin, a good refresh rate is 5 milliseconds. Once you get up into the 8- to 11-millisecond range, that blurring becomes a factor.

Refresh rate can also be expressed in MHz (or cycles), such as 60 MHz, 120 MHz and 240 MHz. In that case, a higher number is best, says Henry Kim, director of product management for Ridgefield Park, N.J.-based Samsung Techwin. “For applications with a lot of activity or motion, such as shopping malls or casinos, monitors designed with higher-MHz refresh rates — 120 MHz or 240 MHz — will display clearer images with less motion blur,” he explains.

Laundry List of Features

In addition to the above criteria, there’s still a rather lengthy laundry list of factors to consider. Some, such as looking for UL and FCC approval, are common-sense. Others, like 3-D comb filters are less so.

Obviously, you want something that’s well-made, so the first thing to look at is the monitor’s fit and finish. Do you need a plastic or metal casing? Do the components fit into that casing? If the case fits and it looks right, you’re good. Otherwise, there may be gaps that could cause the LCD to float and buttons to fit improperly (or not at all).

You’ll also want to look at what inputs — VGA, BNC, HDMI, etc. — the monitor offers and evaluate how the type and number of those inputs meshes with what your application requires. What about audio inputs, which are becoming more and more important?

Power is another consideration, although a decision ultimately comes down to preference. Most monitors use an external power brick, but some use line cords. If you choose one with a power brick, is there a place to store it out of sight?

Another personal preference decision is the location of the controls. They may be on the front, side or back. If you’re dealing with a monitor that will be accessible to the public, the back is best. If controls need to be adjusted frequently, then you’ll want them in the front or side.

Now for the 3D comb filter. In a scene where there are a lot of lines, the comb filter will make those lines crisper and less jagged. This technology is common, Morgan says, but less expensive monitors may be lacking.

Last, but not least, is the warranty. With the 24/7 demands of security, Kim recommends looking for a warranty that goes a full three years and covers parts and replacement.

Reliability

One of the biggest decisions is whether to use a more expensive security-rated monitor or a less costly computer monitor or TV. There are pros and cons with each, so this is can be an area where advances in consumer products cause confusion or frustration for installers and integrators, as well as customers.

“The biggest problem with LCD is that people don’t realize the difference between a security-rated monitor and a TV set. They’re not the same,” Perlin explains.

Because they’re engineered to withstand more rigorous usage than consumer monitors, Kim says monitors designed for industrial or commercial applications, including video surveillance, are the way to go.

“Because of the need to provide continuous operation in mission-critical security applications, these monitors usually offer a longer life span and a more rugged design,” he says.

A standard security monitor will be rated for anywhere from 5,000 to 10,000 hours. However, standard consumer-type monitors aren’t able to operate 24 hours a day and will burn out and need replacement sooner.

Another factor in the security-or-consumer debate is the power supply, which Clinton says will probably be the first component to fail. With “big box” stores or computer manufacturers, monitors tend to be commodity items or loss leaders, so they may throw in a monitor to secure a sale or buy overstocked or discontinued monitors from manufacturers to offer the lowest price possible. Naturally, this has made the consumer monitor industry highly competitive and very price-sensitive, so if manufacturers have to make compromises to keep those costs down, they skimp on power circuits, he says.

“The weakest link will cause the monitor to fail, so everything must be high quality and designed correctly,” he says. “The security industry is considered a commercial application, and most brand-name or box-store monitors will have a clause in the warranty that will void it if the monitor is used in a commercial application.”

While there’s a strong case to be made for choosing a security-rated monitor over a consumer model, the more expensive option isn’t always the most practical, says Tom Donovan, president of systems integration firm Tri-Electronics, based in Hammond, Ind.

“If our customers are using a DVR or an NVR, we go with a computer monitor. Why spend more money on an expensive monitor?” he says.

Donovan, whose company also offers professional video solutions, says cost sensitivities and the way customers are using a monitor often drive the decision to choose a computer monitor over a security-rated model. For example, he says, he can get a computer monitor for $100 or less, while the “right” monitor can cost $1,200 or more. On average, his customers get three to four years’ use from a computer monitor, longer if they turn it off when it’s not in use. If a commercial monitor lasts 10 years, the computer monitor is more cost-effective — even factoring in the cost of replacing it multiple times in those same 10 years.

Another factor in this decision, Donovan says, is that his typical high-end customers are mainly looking to view video on their computer, rather than through a security system.

Size Matters — Sort of

Another area where consumer products have had a great deal of impact is monitor size. In the security world, bigger isn’t always better. For example, if you look at TV manufacturers’ recommended sizes, Perlin says, you’re going to see that those recommendations are much higher than they need to be in a security application.

Determining the best size for security installations depends on a number of factors, including the size of the room, viewing distance, the number of cameras to be monitored, the number of video feeds per monitor and the number of operators. Another factor is aspect ratio, Clinton says. Most 19-inch and smaller monitors display at 1.3 megapixels with a 4:3 aspect ratio. Most 26-inch and larger monitors are 2 megapixel with a 16:9 ratio.

“The aspect ratio is very important in security because analog cameras output at a 4:3 ratio, so when displayed on a wide-screen monitor, the image will be stretched,” he says. “It’s also important to make sure your DVR or NVR software is 16:9 if you want to use a larger monitor.”

So basically, every installation needs to be a custom design that takes all of these parameters into account. While this is true, Perlin has looked into general guidelines for finding the right-sized security monitor. All things being equal, at four feet, a monitor should be 17 to 19 inches. At six feet, 19 to 26 inches; at eight feet, 27 to 32 inches; and at 10 feet, 32 to 40 inches. Any greater distance just isn’t practical, he adds.

Larger monitors also come with a number of drawbacks, Morgan says. For example, the resolution, contrast and brightness of Pegasus CCTV’s 17-inch and 19-inch monitors are identical, but the clarity of the smaller monitor is better. When an image is stretched to fit a larger monitor, the pixels are farther apart, which he says actually can be seen with the human eye. “Personally, I don’t recommend using a bigger monitor because you’re not going to be pleased with the performance,” he advises.

However, in a system that uses a 32-input DVR, you don’t want to use a smaller monitor. His advice? If you have to go up in monitor size, make sure resolution, contrast and clarity also go up proportionally.

Inputs

Many monitors include an HDMI input, which is a great feature if you’re using a DVR or NVR that can feed HDMI signal. Contrary to some popular conception (particularly among consumers) HDMI doesn’t automatically output high-definition. “People automatically assume that HDMI is high-resolution, but it’s not,” Perlin explains.

For example, if you’re using analog equipment, that HDMI cable will merely pass that lower resolution from the DVR to the monitor. The result? Video that’s stretched or has a “mailbox” look. In those situations, a (more expensive) monitor with top-of-the-line screen resolution may be overkill, Morgan says.

“If you have a 480-line camera that’s fed into a DVR, there’s no reason to look at a 32-inch, 1080p monitor because the video isn’t going to display at 1080p,” he says. “It may be the cream of the crop, but why would you want to spend the extra money when it’s not necessary? You’re basically throwing $1,000 in the trash.”

In those situations, Perlin says, VGA inputs, which are available on virtually all monitors and are compatible with DVRs, still are the best bet.

Which brings us to the No. 1 deciding factor in choosing a monitor: customer need and preference.