Essential walls
Traffic management Intertraffic World

Essential walls

Thursday, 18 April 2019
Traffic control rooms can be future-proofed with versatile up-scaling of video wall technology.

The continuing challenge of control room design has always been that of scale. How to scale-up the visual workspace so it can be seen and shared by multiple operators; or how to increase the amount of useful data available to operators without overloading the system with complexity.

For much of the 20th century, the main technical challenge faced by control room designers was that of how to physically display mission-critical data so that it was visible and accessible to everyone who needed it. The advent of the first rear-projection video walls in the mid-1980s provided a solid solution for this problem and henceforth became the main vector of development that the industry followed for the next three decades.

Today, we still find systems integrators facing problems of scalability. But ironically the problem of scalability itself has grown. The challenge is no longer just that of building bigger and more detailed data displays, but also that of overcoming the limitations of the infrastructure that supports them. Integrators now also have to plan for the ever-accelerating advance of technology and rapidly changing operational demands that can overtake system capabilities within timescales now measured in years, rather than decades, as used to be the case.

Video wall evolution

The rear-projection video wall remains the mainstay of control room display. In its modern form, based on high-powered LED illumination and digital light processing (DLP) image processing, the video wall is a versatile, effective and reliable way to display data. Advances in design mean that the service life of units has increased dramatically, from just a few years to decades. At the same time, removal of dependence on consumables like mercury lamps means that cost of ownership has plummeted. Some Mitsubishi Electric DLP video walls, for example, now offer 15 years of maintenance-free operation. So why, then, if DLP technology has proven so decisively effective over such a long period, are integrators still facing problems of display scalability?

The scalability challenge facing systems integrators today is not so much how to create displays big enough for control room applications, as how to effectively visualize the vastly increased volume of data flowing into a modern control room facility. The evolution from analog to digital and finally to IP-based infrastructures, has opened up tremendous opportunities. But with it comes the problem of how to ensure that information remains accessible and useful for operators. Generally, that means finding ways to squeeze more data onto a finite-sized screen.

The total amount of pixel ‘real estate’ available on the display – its total resolution – is now the most important factor. All modern DLP rear-projection units are digital displays, with fixed resolutions following standard conventions such as Full HD, SXGA+, WUXGA, etc. High total resolution video walls are built by adding more units until the total pixel resolution is sufficient for the requirement. However, bigger is not always better: in reality there are practical limits to how large it’s possible to go, both physically and economically. DLP units take up a comparatively large amount of floor area; they place increasing demands upon the air handling system and impose a substantial floor loading. And, while it is possible to create bigger, more visible displays using larger screen size units – 80in diagonal as opposed to the more usual 60in or 70in types – this increase in size comes at the cost of reduced light output, which in turn means they cannot be used in naturally lit environments.

A new view

In the past few years, an alternative has emerged that has the potential to become the display technology of choice in many of these larger applications. Direct View LED takes a completely different approach – ironically a closer relative to the old cathode ray tube than the DLP technology that replaced it. In Direct View LED, individual pixels are comprised of tiny packages of red, blue and green high-intensity LEDs. By mounting these LED packages very closely together – usually 1.5mm or less – it is possible to create high-resolution displays, viewable even at the close distances usually found in control rooms.

LED offers several compelling advantages over a very large DLP video wall. Firstly, resolution. A Direct View LED display such as Mitsubishi’s 15NP is built from individual tiles fitted together to create a screen of the desired size and resolution. The number of pixels on each tile is much less than an individual DLP display. The overall screen resolution is therefore not fixed by multiples of conventional standards such as WUXGA, and can be tailored specifically for the application. Secondly, the tiles themselves are much slimmer and lighter than a DLP projection unit. Whereas Mitsubishi’s slimmest DLP projector unit is 550mm (22in) deep, its LED tile is less than 100mm (4in). This means less floor area needs to be occupied and the structural loading requirement is greatly reduced, making it possible to install large screens in locations that would not be possible by other means. Thirdly, the light output of Direct View LED by area far exceeds that of large format DLP projection units. It is therefore possible to create displays that are clearly visible even in daylight conditions, creating a much more comfortable environment for operators.

Essential walls

Challenges overcome

While Direct View LED offers an alternative display option to address the limitations of DLP, integrators still face the challenge of implementing a scalable display content management solution. For many years the standard method has been to rely on a dedicated hardware controller to handle the routing and processing of source data for display. But while today’s processors are extremely powerful, hardware-based solutions will always be less able to adapt to evolving requirements. A new approach is to take advantage of distributed computational power to create a more fluid and adaptable control architecture, which is able to scale itself intelligently to handle varying demands.

One example is Mitsubishi Electric’s S-SF software suite, which enables IP network-based display systems to operate more efficiently and with greater scalability. The versatility of native IP command and control visualization networks allow systems to adapt easily to future needs and offers the long-term cost benefits derived from the exceptionally long operating lifetimes of modern DLP and LED displays to be fully realized.

The S-SF suite consists of five applications: Display Agent, Multicast Converter, Application Server, S-SF Control and S-SF Master. Together, they create a native IP-based system capable of handling data traffic from any networked source device, such as sensors, image processors, CCTV cameras or data stores, synchronizing and sharing content instantly across any number of locations with minimal latency. Dynamic processing means content such a Scada-style vector graphics can be scaled to any size with no loss of quality or performance. S-SF makes it possible to design more efficient, more flexible decision-making environments, for more effective command and control room operations.

Using the S-SF architecture, control room video walls no longer require a single dedicated display wall processor. Instead, the system is built from a number of individual self-contained processors. The most commonly used devices are known as NUCs (next units of computing) – based around standard Intel processors. Basing the hardware on standard, widely-available network components removes the need to develop and debug proprietary hardware or operating systems and adds greater long-term versatility. Fault tolerance is assured due to the multiple redundancies inherent in the distributed network architecture. If one network node develops a fault, its role is instantly assigned to another node to achieve a completely seamless failsafe response and guaranteed 24/7, zero-downtime performance. The result is a more reliable, cost-efficient system that is able to scale easily.

Despite all the advances in personal workstations over the last decade, the control room with its central large screen display is still by far the preferred approach in command and control, and it looks likely to remain so in future. The challenge now is to design-in the versatility to cope with rapidly evolving demands. While it’s likely that DLP video wall and hardware processing will remain the logical choice in many applications, its equally clear that alternative display technologies and distributed processing potentially offer integrators a far more open-ended option when it comes to tackling the age-old challenge of scale.

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