Analysis of the Development Trend of Security Screen Mosaic Wall

With the continuous development of the social economy, people are increasingly demanding various kinds of information in daily work and life, which greatly promotes the application of large-screen videowalls. Simply speaking, large-screen video wall is an integrated display system. The two most commonly used projectors are LED and projection. Among them, projection is currently used three technologies LCD, DLP and LCOS. The use of projection technology video wall is relatively low price, and the picture quality and stability are relatively high, so the most cost-effective, is currently the mainstream product in the field of video wall. Although the LED splicing wall is relatively high in price, it is widely used outdoors for digital display because of its characteristics of being resistant to sunlight and wind and rain. In addition, there are LCD liquid crystal and PDP plasma technology.

Mr. Zhao Handing, secretary-general of the large-screen projection display branch of the China Electronics Video Industry Association, said, “The video wall is not dispensable, but it can greatly improve work efficiency. For example, in the public traffic dispatch department, the use of video wall can be displayed at the same time. A lot of pictures, so that the traffic conditions of all road sections are clear at a glance, easy to command and dispatch. “It can be seen that the mosaic wall is playing an important role in commanding and dispatching and other large departments and places.

At present, the large-screen splicing system has been widely used in exhibition halls, sports venues, news centers, television studios, meteorological stations, train stations, airports, entertainment plazas, military combat command centers, traffic command systems, public security 110 command systems, and power dispatch. Flood control, shopping malls, banks, outdoor advertising, etc. Because of the different circumstances in each industry, the application methods have their own characteristics. In addition, different types of videowalls also have their own different advantages, but also have their own specific needs environment. Therefore, with the development of products in the development of applications, the direction of the future development of the mosaic wall is closely related to the application.

Diversification of various types of videowalls is a different technology in competition. It can be seen that the LCD liquid crystal splicing wall will become the mainstream in the future in terms of small-size monitoring, and DLP is still the future development direction in terms of large size.

Although DLP rear-projection video mosaic wall has the defects of large size and short life span, it still occupies the current major market due to its small seams and good visual effects. In addition, DLP has a longer development time and a wider promotion. Although some disadvantages are exposed in the process of large-scale use, DLP manufacturers are gradually improving their technology. They try to make the DLP cabinet bigger and thinner. Smaller, thus achieving screen integration.

DLP is occupying half of the country and LCD is a rising star. The display unit of the splicing system can be divided into many types according to its working principle. The more common ones are: CRT (cathode ray tube), LCD (liquid crystal), PDP (plasma), DLP (back projection), and the like. Looking at the current situation of the display unit, the CRT has gone from being red-hot to late, and it has already become a yellow flower; the DLP rear-projection splicing system is currently the mainstream product, occupies most of the country; LCDs that have recently become rising stars have seen rapid development in recent years.

With the development of technology and the increase in demand, the CRT can no longer meet the needs of users. Currently, it has basically withdrawn from the market. DLP has the characteristics of image clarity, brightness, color, and viewing angle and is still the most widely used technology in the market. In addition, since the DLP splicing curtain wall uses a projection method, its splicing gap can be made very small (3-5 mm), but due to the unevenness of its screen brightness, the overall picture has a lower brightness at the splicing edge, and each unit The brightness of the center part is relatively high, so it also affects the look and feel of the splicing curtain wall to some extent.

The LCD splicing curtain wall adopts the LCD screen as the splicing unit, and is a curtain wall technology that follows the CRT curtain wall, DLP curtain wall, and PDP curtain wall. It has a service life of 50,000 to 80,000 hours, and has the characteristics of stable quality and low maintenance cost. There is no strict requirement for seams, and LCD can be regarded as the most cost-effective curtain wall. Judging from the current situation at home and abroad, all high-end curtain wall systems have adopted LCD splicing curtain walls. As the technology matures further, the future market of LCD curtain walls is very promising.

The future splicing wall will also be networked, and the functions will be further enhanced. Not only can it be used for terminal display, but also some useful functions can be added to achieve added value. And the most important thing is to achieve household consumption.

A more complete and more perfect picture will always give people an extraordinary visual. At present, whether it is a large-scale rear projection screen splicing, or LCD splicing systems, the gap between the screen can not make people satisfied. At present, the vast majority of large-scale rear projection mosaic display systems are seamed, there is no true seamless mosaic system, in addition, there are few manufacturers that can do more than one row and many rows; so how to achieve real significance The seamless splicing of the large-scale rear-projection splicing display system and the splicing of the system picture to be more complete and perfect are still the pursuit of excellence by the manufacturers.

A seamless edge-splicing display technology is gradually becoming a solution to this pursuit. It is reported that in the fusion splicing using the entire screen, eliminating the physical gap between the existing screen splicing, so that the entire display screen image remains intact.

Continuous innovation of technology With the wider application of large-screen videowalls, the splicing technology is constantly improving, but due to the lack of bandwidth of the PCI bus, it has become a key issue that has plagued the large-screen splicing system to a large-scale development. Take the system of 81 display units as an example to analyze the bottleneck problem of PCI bus bandwidth: After calculation, the time it takes to transfer from the memory via PCI to display an image (243M data) in an ideal state is 1.84 seconds, and the actual operation time Other software influences, device interruptions, hard disk access speeds, and the amount of memory often increase the image data transfer time significantly, or cause unacceptable jitter effects during image data transmission. It can be seen that, due to the limitations of the PCI bus bandwidth, traditional processors simply cannot perform the ability to normally drive 81 displays.

Embedded splicing mode is the trend of the times There are basically three different splicing methods for the large-screen splicing wall on the market. One is PCI card type; the other is external splicing controller mode; and the third is embedded mode.

PCI card type working principle is through the industrial computer, using a multi-screen splicing card, a complete video image is first divided into M Х N sub-video signals, and then these sub-video signals are respectively transmitted to each corresponding unit on the mosaic wall. To achieve the purpose of large-screen display. However, due to the limited computing power of IPCs, currently the best performance IPC can only achieve 4Х4 splicing, limiting the number of splicing units.

External drag stitching controller can also be called big screen splicer, video wall controller or video wall splicer. Its main function is to divide a complete image signal into N blocks and then allocate it to N video display units (such as rear projection Unit) completes the formation of a large screen with multiple common video units. It can support the simultaneous access of multiple video devices to achieve the functional requirements of the mosaic wall. It is called dragging because it is divided into two separate parts, one part is the display part, which can be composed of ordinary rear projection units such as rear projection TVs; the other part is the stitching controller. Its function is to realize that a plurality of physical outputs are combined into one resolution-superimposed display output so that the screen displays a picture.

This splicing controller has a variety of methods to implement. It can be embedded, it can be inserted card, or both. Simply put, it is like a picture splitter, but it is only after it is enlarged and divided, so it is generally easy to install, the wiring is relatively simple, there are no many modules and other advantages; but the disadvantages are also very obvious, such as once When a certain road fails, it is difficult to repair; the hue between the units, the field phase, etc. are difficult to adjust, and the image quality is poor.

The working principle of the embedded mosaic wall is that each splicing unit has an independent video processing module, and the complete signal is sent to each unit through the matrix, and the video processing is performed separately, the part that should be displayed is divided, and the part of the signal is amplified. After the display, to achieve the purpose of large-screen display splicing. Due to their respective processing, the number of stitched units can theoretically be infinite.

Therefore, the basic difference between PCI card-type splicing and embedded splicing is that after the former splits the mother signal, each sub-signal must be magnified and the latter only magnifies the part that should be displayed. Therefore, the former The amount of computation is large, and the resolution is determined by the computer and the corresponding PCI card; the latter has a small amount of computation and the resolution is determined by its own embedded processing module.

In addition, the features of embedded splicing also include:

Easy to use: Because its software is developed specifically for the product, users generally do well without training.

The system is highly stable: it will not be interfered by various viruses from the network or computer systems, because its software is solidified in the FLASH and cannot be changed.

System startup speed: non-embedded systems generally have to be built on Unix or WINDOWS in order to achieve its function, so that the system must start these before running the splicing program, the whole machine starts much slower.

Low cost: The software of the embedded system must be developed by itself. The non-embedded system needs to purchase the operating system such as WINDOWS. The price is small and the structure is compact: it is precisely because of the advantages of the embedded splicing that the current market applications Compared with the traditional PCI card-based splicing, there are more production houses in this area, but in the future it will still develop towards embedded splicing.

In response to this problem, some manufacturers have proposed some solutions:

Distributed master-slave processor architecture technology contains distributed master-slave processor technology. It has a full-screen, high-resolution, single-screen display capability. It also has the ability to flexibly partition multiple applications, whether it is a single logic screen application or a partition. Applications can achieve rapid synchronization display. At present, the rear projection splicing display system adopting this technology has a maximum resolution of 100M pixels (100 million pixels) and the display speed is equivalent to the display speed of an ordinary 16-channel multi-screen processor system.

Bottom system switching architecture technology manufacturers have developed a new bus structure, the core is the backplane system switching architecture. The traditional bus architecture, such as the PCI bus, is shared by all peripheral connections, thus restricting the transmission of large amounts of data information in the control room environment. The backplane system switching architecture provides up to 4Gb/s for each peripheral slot. s transmission bandwidth. The peripheral board connects to the high-bandwidth switch fabric card through the backplane to ensure that the data is transmitted through the best path and provide fast and high-quality screen data. By adding an optional serial switch card, the data bandwidth can be increased to 8Gb/s per slot. This ensures the smooth display of various signals regardless of the size of the display, and ensures continuous and stable operation of the system.

To sum up, with the continuous development of science and technology, the technology level of the large-screen video wall will become more and more mature, the cost will be greatly reduced, and the application prospect will be broader. (Author: Shanghai Security Service Corporation)