Security monitoring functions and operations can adopt a range of applications, configurations and technologies. In today's world, security is more than monitoring the status of doors and windows. We now monitor our surroundings and environment, traffic flow of vehicles and pedestrians, deliveries to our buildings and even utilities serving our properties. There are several different technologies and devices available to help us do this. The one common factor is that we must use our sense of vision and discernment to evaluate the information coming from these various technologies.
Traditionally, security centers employed several video and computer data displays. With the need for expanded and more sophisticated forms of monitoring increasing, additional monitoring screens and images are now required to display this vital information. The security control center has evolved into a master information command-and-control center, with facilities for monitoring building mission-critical applications and environmental services. Emergency news broadcasts, strategic communications, weather and logistics control, once part of building operations, are now often under the authority of the modern security center.
As these new requirements are assigned to the security sector, the area to accommodate the increased monitoring responsibilities inherently increases. The added number of system displays and the space to physically locate them can expand drastically. Unfortunately, all too often this expansion has forced a horizontal growth of the monitoring console to enormous configurations, rendering the human ergonomics and operating conditions of the space to a rather inefficient and unmanageable status.
Sharing New Technology
As we begin to explore better ways to address these monitoring necessities, we find that newer, cutting-edge presentation display technologies once reserved for the corporate boardroom are now making their way into the security command center. Buildings and grounds departments, IT departments, audio-visual departments and security forces have entered into a world of shared technology and strategic information exchange that is paramount in the protection of personnel and property. To this end, high-technology display devices and systems are playing a more critical role in serving the security and defense of our resources.
Smaller cathode ray tube (CRT) monitors, once the mainstay of the security center, are making way for larger liquid crystal display (LCD) and plasma flat-panel devices. High-resolution video projectors using LCD and Digital Light Processing (DLP?) technologies are now used to display CCTV motion video as well as access control, building environmental and intrusion detection screen images. These larger display devices and systems are providing a level of flexibility that was not commonly found in the security arena a few years ago.
We will briefly explore some of these display technologies, the processing electronics behind them and some of the advantages and benefits that can be realized when they are incorporated into the security monitoring and surveillance application.
Advancements in Image Size
For decades, the workhorse in surveillance monitoring was the nine-inch diagonal CRT video monitor for viewing security CCTV analog camera images. In many cases, dozens of these were installed to accommodate the number of cameras in an installation. This typical monitor in a 4:3 width-to-height ratio provides a surface viewing area slightly less than 40 square inches. In many cases, larger CRT monitors, such as 17-inch diagonal displays, are used for automatic alarm-initiated call-up viewing or viewing archived video. These offer a much larger viewing area of 139 square inches.
A typical 40-inch diagonal plasma or large LCD display in a 16:9 width-to-height ratio provides a surface viewing area of approximately 800 square inches (depending on manufacturer) or about 20 times the viewing area of the nine-inch diagonal monitor. Plasma screens in sizes of 50- and 60-inch diagonal are common today for public messaging, marketing and formal presentation applications. A typical 50-inch diagonal plasma display increases the available image viewing area to more than 1,000 square inches, and the 60-inch provides more than 1,600. At present, flat-panel LCD monitors are available in up to 45-inch diagonal. Fifty- and 60-inch monitors will soon be available.
One must keep in mind, however, that these calculations do not represent a direct correlation between standard CCTV imaging in a 3:4 aspect ratio and the 16:9 aspect ratio of many larger flat-panel displays. By incorporating standard audio-visual industry presentation techniques, an outboard LCD or DLP projection device and front or rear projection screen can be used to produce image sizes that are virtually unlimited. With the wide-angle lenses and light-path-folding mirrors available today, large image sizes projected in relatively small areas are certainly possible.
Video walls, using individually sealed LCD and DLP projection cubes, can be arranged in vertical and horizontal stacked configurations to adapt to the size or space constraints of an existing building or security command center. These cube displays are available in diagonal screen sizes from 40 inches to 70 inches, and when constructed in a stacked configuration, can produce a nearly mullion-less single large screen array in multiple sizes. Several manufacturers now offer units with mullion surrounds measuring as little as 0.5mm in thickness. These larger image-producing cube displays are commonly used in many 911 tactical analysis centers and 24/7 emergency alert centers. They are enabling users to expedite emergency situation awareness and improve action resolution.
All About Space Saving
Do we need images that large in a typical security center? Certainly not. What we do need, however, is the means to display numerous images in the smallest physical area possible. With the video processing components available today it is relatively simple to simultaneously display numerous camera and computer data images on a single large display device.
Security system CCTV integrators have been doing this for years with quad video processors and larger CRT monitors. Now we are not only able to incorporate computer data information into this same equation, but we can mix and match CCTV video camera and computer data information as multiple images in two, four, eight, 16 and more individual images on a single, large screen. We are also able to resize and reposition these images within the screen in real time.
It is possible to display 16 typical CCTV images on a single 42-inch diagonal display device in much the same size as was the standard in the security industry. Although the usable width of the 16:9 format would not be completely filled using nine-inch diagonal images in a 4:3 ratio, a plasma or LCD device can be made to expand the format ratio to make use of the full 16:9 image area available.
Looking at this situation using typical rack-mounted CRT monitors and taking into account the exterior dimensions, a total area to adapt 16, nine-inch images would require 1,600 square inches of physical space, or 48 standard EIA units. The overall equivalent using the larger plasma or LCD display equates to slightly more than 1,000 square inches, or approximately 64 percent less surface space for the same image display area. Using fewer of the larger display devices in lieu of many smaller screens clearly presents significant space savings. It also provides the additional benefits of reduced overall heat generation and power loads.
Image size is not the only parameter to consider as you decide whether to use these display technologies. Resolution, brightness and contrast must also be considered in context of the images to be displayed and the environment in which they are to be displayed.
A typical plasma or LCD flat-panel display may have the capability to display an XGA (1024 x 768 pixels) graphics-standard computer signal. When displaying multiple images on the same display, each image would share the total available number of pixels, thereby reducing the overall number of pixels available for each image. As a result, the images will not be reproduced with the same clarity or sharpness that they would if they were displayed in their native resolution as the only image on the display.
Conversely, if a single image is displayed over multiple displays, as in a true video wall application, the pixel capacity of each display is summed. As an example, four displays with individual resolution capacities of 1024 x 768 arranged in a two-by-two configuration would provide a resolution capacity of 2048 x 1536. Therefore, a UXGA (1600 x 1200 pixels) graphics-standard computer image could be reproduced as a single image with no degradation of the original signal. Viewing distances from the operator to the screens, along with angle of view on both the horizontal and vertical planes, are other considerations in the placement of screens, as are reflective or direct screen materials and optical characteristics. As with any display device, special attention must be given to location and proximity to extraneous light-producing devices, which can cause screen glare and in severe cases completely wash out a projected or displayed image.
As previously mentioned, the processing components that enable us to display multiple images on a single screen or in the context of a virtual video wall can take on various levels of sophistication and offer a wide range of flexibility. Simple CCTV signals to high-resolution, computer-generated graphic signals can be accommodated by the electronics available and can be mixed and matched on a single screen or multiple screens as the application or need requires.
Standard equipment interface control protocols for automation processing have also been introduced to allow computer-generated images, such as alarm and access control monitoring, fire monitoring and virtual floor plans, to be automatically selected and displayed upon an exclusive alarm event or condition. Displays and processing components featuring redundant lamps and power supplies, hot swapping components and extended life expectancies have already been developed for mission-critical 24/7 applications and proven in the market in numerous utility and network monitoring command-and-control centers. Software-switching programs have been developed to allow screen image relocation of critical displayed information at the touch of a button, touch screen or mouse click without any need for hardware reconfiguring.
As you can see, there are many questions you must answer in order to determine the best overall display concept for your monitoring needs. There are certainly inherent advantages and disadvantages to each of the display technologies mentioned here. No single technology or display technique is appropriate to support all monitoring applications or environments. The visual material content, signal types and properties of images, physical environment, viewing angles, component useful life span, screen image burn-in, refresh rates, pixel burn-in, electrical power requirements, heat generation and costs are only a sampling of the issues that must be analyzed and evaluated.
A carefully planned approach must be established, taking into account many of the above-mentioned factors and dynamics, before implementation. One must assess operational impact versus cost of implementing such surveillance system displays. The costs associated with implementing these high-tech display devices and processing electronics can be quite high. However, the costs associated with not implementing them may be even higher.
Mr. Phillip Schramm is a consultant with Sako & Associates Inc. Located in the Arlington Heights/Chicago office, Mr. Schramm has 30 years of project experience in the design of facilities for audio-visual and communication systems as well as systems designs themselves. To learn more about SAKO and their services, visit www.sakosecurity.com.