Design of Large and Complex Display Systems

Eric H§nique, Soeren Lindegaard, and Brian Hunt

CONTENTS

4.1 Introduction………………………………………………………………………………………………. 84

4.2 Applications for Large Screen Systems in Control Rooms………………………… 86

4.3 Why Use Large Screens in Control Rooms?………………………………………………. 87

4.3.1 Defining Requirements………………………………………………………………….. 88

4.3.2 Visualised Information…………………………………………………………………. 89

4.4 Basics of Viewing and Seeing……………………………………………………………………. 89

4.4.1 The Human Eye…………………………………………………………………………….. 89

4.4.2 Contrast………………………………………………………………………………………… 91

4.4.3 Colours………………………………………………………………………………………….. 92

4.4.4 Viewing…………………………………………………………………………………………. 93

4.4.4.1 Fundamentals of Viewing………………………………………………… 93

4.4.4.2 Viewing Angles………………………………………………………………… 94

4.4.4.3 Brightness and Contrast………………………………………………….. 95

4.4.4.4 Viewing Distances……………………………………………………………. 96

4.4.5 Ambient Light……………………………………………………………………………….. 97

4.4.6 Controlling Daylight………………………………………………………………………. 98

4.4.7 Image Quality……………………………………………………………………………….. 98

4.4.8 The Weakest Link in the Chain Decides the Perceived Result……… 99

4.5 Display Technologies…………………………………………………………………………………. 99

4.5.1 Cathode Ray Tube (CRT) Monitor Wall…………………………………….. 100

4.5.2 Mimic Panel Display…………………………………………………………………… 100

4.5.3 Projection Displays……………………………………………………………………… 102

4.5.3.1 Front Projection Displays……………………………………………….. 102

4.5.3.2 Front Projection Screen Types………………………………………. 103

4.5.3.3 Application Sectors……………………………………………………….. 104

4.5.3.4 Rear Projection Displays……………………………………………….. 104

4.5.3.5 Stand-Alone Devices……………………………………………………… 105

4.5.3.6 Cube Display Wall…………………………………………………………. 106

4.5.4 Rear Projection Screen Types……………………………………………………… 106

4.5.5 Diffusion Screen Design………………………………………………………………. 107

4.5.6 Single-Element Optical Screen Design………………………………………… 109

4.5.7 Dual-Element Optical Screen Design…………………………………………. 110

4.5.8 Selection of Rear Projection Screens…………………………………………… 110

4.5.9 Liquid Crystal Display (LCD) Cubes……………………………………………. 111

4.5.10 DLP Cubes…………………………………………………………………………………. 112

4.5.10.1 The Greyscale Image…………………………………………………….. 112

4.5.10.2 Adding Colour………………………………………………………………. 112

4.5.10.3 Applications and Configurations of a One-Chip DLP

Projection System…………………………………………………………… 114

4.5.10.4 Advantages of DLP Technology…………………………………… 114

4.5.11 Thin Film Transistor LCD Monitors…………………………………………… 114

4.5.12 LCD Monitor Wall Narrow Bezel……………………………………………….. 116

4.5.13 Plasma Screen Displays……………………………………………………………… 116

4.5.14 Seamless Plasma Screens…………………………………………………………… 117

4.6 The Right Display Technology…………………………………………………………………….. 118

4.6.1 Display Systems…………………………………………………………………………… 119

4.6.2 Graphics Controller……………………………………………………………………… 121

4.6.3 Wall Management Software……………………………………………………….. 123

4.6.4 Installation of Large Screen Systems…………………………………………… 125

4.6.5 Screen Mullion……………………………………………………………………………… 126

4.6.6 Environmental Aspects……………………………………………………………….. 127

4.6.7 Servicing a DLP Cube Wall…………………………………………………………. 127

Glossary……………………………………………………………………………………………………………… 127

References and Further Reading………………………………………………………………………… 130

4.1 INTRODUCTION

Control rooms and control centres tend to have something in common, even though control rooms are used in several areas of application. The specific types of applica­tions are many and varied and include telecommunication, military and aerospace, industry, energy (generation, distribution, and transmission), security (national and domestic), water (production, sewage, and purification), traffic monitoring and con­trol (roads, tunnels), airports, railway and metro networks, police and fire depart­ments, emergency services and call centres, data centres for governments, and commercial enterprises. In general, the central medium of such a room nowadays is a large screen system. Other terms for large screen display include: video wall, large display screen, large video screen, display wall, large video screen, large screen dis­play, and monitor wall. Other technical and specific terms used in connection with this display screen technology are contained in a glossary at the end of this chapter.

The increasing volume of traffic and the resulting traffic jams, the growing traf­fic network, and environmental aspects make observation and control of the traffic – related systems necessary. Data and information transmitted from traffic detectors, video observation systems, and other sources have to be administered, distributed, and visualised centrally in traffic management centres. This guarantees a timely control and administration of this data and thus a productive and efficient use of the existing traffic resources. In recent years, headline-catching accidents and fires in road and train tunnels have encouraged governments to launch new programmes to reinforce the security in tunnels. As a result of such initiatives, significant invest­ments in control room systems have been made and are still going on. This makes it also necessary to invest in key control room equipment such as large screen systems, which can help reduce dramatically the reaction times to problems.

Effective control and security of transportation systems depends substantially on the availability of all necessary information in the control rooms. Safety and the smooth operations of roads, highways, railways, and air traffic are facilitated by competent operators manning the control rooms. In railway networks, the stations, platforms and station concourses, tram termini and crossings, and subway networks warrant close attention from the control room operators. On waterways, the bridges, canals, and shipping flow are key areas where vigilance ensures efficient operations. Air traffic controllers ensure safety in the air while their colleagues monitor pedes­trian and vehicular traffic around and within the terminal approach roads and build­ings. A key resource for these professionals in their work is the large screen wall that is the central unit for all operational tasks in the control room. All applications, software, and video signals can be displayed in real time on the projection wall, so they can be rapidly processed and transmitted by the operators.

Large screen walls are used in these operational fields for the following applications: graphics (maps, road and railway networks, and time schedules), GPS applications, camera signals (traffic detectors, signal systems on main traffic junctions, railways, and airports), observation systems, alarm management, monitoring of the ventilation systems in tunnels, remote control, and other transport systems and software.

In the crucial activities involved in water supply, purification, and production, a growing demand for water, energy, sewage facilities, and production capacities has led to a growing need for increasing amounts of relevant data and information. Quan­tities of data have increased hand-in-hand with rapid changes in information technol­ogy and processing. Nowadays, the most common systems used in management and control centres are SCADA (supervisory control and data acquisition) systems and DCS (distributed control system) in combination with large screen displays. Using these technologies, the operators can observe in real-time flow diagrams, pumps, valves, pressures, reservoirs, metres, status information, and other relevant data. At the same time, observation cameras situated at strategic points in the processes make it possible to visualise the state of the process and relay signals to control the process flows.

Since this enables a total surveillance of the entire production facility at any time, it is possible to identify failures and to react on malfunctions with very short response times. Given the strategic nature of this industry, the security aspect is in the foreground. This factor has an important influence on the productivity and effi­ciency of a plant. Similar situations apply in the observation and control of nuclear power plants, water plants, gas and oil distribution facilities, production plants, as well as waste services such as sewerage plants. In these industrial processes, secu­rity and safety are tightly connected with the image quality and functionality of the master display in the control room.

The most common applications that are displayed, edited, and managed on large screen displays are SCADA or DCS applications (pipelines, production networks, pump stations, and so forth), graphics (production survey, networks, customer-spe­cific applications, and so on), observation cameras, and further supplying and dis­tributing applications.

Large screen walls also play a key role in the control rooms and the data cen­tres of the telecommunication (network operating centres [NOCs]) branch of fixed or mobile phone companies, and sometimes even the world-spanning networks. Complex graphics (maps, network diagrams, and customer-specific applications), high-quality voice and data streams, network resources, fault management (network control, service, fault removal, availability), security management (network security, redundancy, tests), accounting management (exact account calculation, account sur­veillance), and quality management are controlled and observed on the large screen displays in control rooms of the telecommunications industries.

Rising levels of criminal and terrorist activities, not only since the incidents of September 11th, have predictably led to a growing demand of observation in the security sector. In security centres the relevant data and video signals have to be available for continuous (24 hours a day, 7 days per week) operation in real time. Most important for a reliable security system is a perfect interaction of observa­tion, control, management, planning, and coordination of activities. Therefore the concerned services all operate interconnected to control and coordinate their activi­ties. Some recent terrorist attempts had been averted because of the closed-circuit television (CCTV) surveillance. Police officers could quickly apprehend suspected terrorists because of this surveillance and the alertness of the control room opera­tors. In the military sector, surveillance can be conducted via surveillance input provided by unmanned aerial vehicles (UAVs), also called drones. Cameras mounted on the drones are able to record real-time images from high or low altitudes. Dif­ferent types of lenses fitted to the cameras allow the images to be taken by day, at night, and through cloud cover. Relayed by satellite to large screens in command and control centres and collated with incoming data from other sources, the images enable relevant decision makers to deploy available personnel and weaponry in the air and on the ground.

Apart from these roles, large display systems are used to improve the reaction time and to increase the output in data centres and production facilities. The use of large display systems has played a role in constantly increasing productivity and efficiency. Again, the central medium in all those control rooms is a large screen system. Such a large screen system is in general used to collect, visualise, and dis­tribute data and information to give a complete overview of the ongoing situations to a number of users or operators. The management is also quickly able to receive an overview on what is happening inside the control room.