In the design of LCD splicing large screen display system, according to the basic needs of users, based on the rationality of architecture, high reliability of operation, the mainstream of products and the rationality of cost, advanced, safe, reliable and efficient system solutions are provided. Convenient use and maintenance, advanced equipment, reliable operation and easy expansion; Under the premise of low cost, it fully meets the various needs of users in image quality, line transmission, image processing, signal control and so on.
1, the system meets the relevant standards of relevant departments;
2. Under the premise of ensuring the quality, protect the system investment and low operating cost, and save the total investment of users;
3. It has high reliability to ensure the safe operation of the system;
4, adapt to the real-time monitoring and management of the work site;
5, the image is clear and the control is flexible;
6, flexible structure, convenient to provide fully compatible support for other standard equipment;
7. Ensure to meet the demand of future monitoring point growth; Based on the on-the-spot investigation of the station, the principle of strictly controlling passenger flow and personnel operation is decided in this system construction, that is, monitoring passenger flow passages, waiting rooms, platforms, overpasses, ticket sales, luggage, station entrances and exits, ticket checking, station square, underground passage, rain gallery, finance, staff lounge on duty and other places to the maximum extent. Ensure the unified coordination performance of a game of chess in the whole station after the implementation of the system, and ensure the rigor, real-time and uninterrupted monitoring of all parts. In the design of defense points, we should try our best to meet the needs of key areas and not set up blind spots, so that violations of law and discipline can disappear.
The video signal is collected by the front camera and transmitted to the control center through optical fiber. The video signal is divided into two parts through the video distributor, and one part enters the video switching matrix. By operating the matrix keyboard, the image is displayed on the TV wall. Each controlled display can display any graphics, and can realize manual switching, programming switching, grouping switching, back-and-forth switching, timing switching and other graphics switching modes.
Control signals of the matrix pair for pan/tilt and lens are transmitted to the front-end decoder through the protocol adapter and control cable to operate the pan/tilt lens.
The other video signal enters the hard disk video recorder for data storage. And display multi-picture images in real time on 17 inch display screen. 1, image processing and extended functions
The external stitching processor adopts professional image processing switching module, based on FPGA hardware architecture, hardware graphics parallel processing technology and high-speed digital signal exchange system, independent of the system bus, and adopts parallel high-speed graphics processing technology to realize unified processing of multi-channel signals with high processing efficiency. Up to 128 VGA signal real-time display and 128 composite video real-time display can be supported, which can satisfy customers' arbitrary splicing and combination expansion.
2, any picture combination stitching function
There are a variety of arbitrary picture combination splicing methods, which can be extended to 15 rows and 15 columns at most, and all units can be switched and combined at will.
3. High bandwidth and large signal input.
A single device can realize 72 channels of high-definition input and 72 channels of high-definition output at most, and a single device for ordinary video input can realize 256 channels of input. Each output card 10GB, and the independent bandwidth of the input card is 4GB. When the 1920× 1080 HD signal window's 144 channel is opened at the same time, there is no frame jump and no delay. Four devices work together, and 288 splicing walls can be realized under the condition of ensuring complete synchronization and real-time.
4, a variety of input interfaces
It has multiple signal input interfaces, such as DVI/AV/S terminal /YPBPR/HDMI/VGA. Users may have a lot of doubts when faced with screen selection. Seven screen selection criteria are provided for different application environments.
I. Types of video projectors
CRT technology: CRT projector is what we usually call a three-gun projector, which consists of three projection tubes. The CRT projector decomposes the input signal source into the fluorescent screens of three CRT tubes, R (red), G (green) and B (blue). The luminous signals are amplified and converged under the action of high voltage, and color images are displayed on the big screen. This kind of projector has the characteristics of rich images and high resolution, but the disadvantage is that the brightness is usually low.
LCD technology: LCD technology uses traditional light sources, usually metal halide lamps. The three primary colors of red, green and blue light are completed by three independent liquid crystal panels, and the three primary colors can reach the screen for imaging almost at the same time.
DLP technology: The full English name of DLP is Digital Light Processor, which means "Digital Optical Processor". This technology is a patented technology developed by Texas Instruments, and it is a projection technology with DMD (Digital Micro Mirror Device) as the imaging device. Digital micro-mirror is used as the imaging device of light valve. Even a single DMD is composed of many micromirrors, and the physical resolution of DLP projector is determined by the number of micromirrors. Many micromirrors form DMD together, and the reflected image of each micromirror represents a pixel.
D-ILA technology: D-ILA is a technology that directly drives the image light source amplifier. The core component of this technology is reflective active matrix liquid crystal panel on silicon, commonly known as reflective liquid crystal panel (LCOS), so this technology is called reflective liquid crystal technology in the industry. The advantage of this technology is high brightness and contrast.
LCOS technology: This projection technology uses CMOS integrated circuit chip coated with liquid crystal silicon as the substrate of reflective LCD, which is polished by advanced technology and plated with aluminum as the reflective layer to form a CMOS substrate. Then the CMOS substrate is bonded to the glass substrate with transparent electrodes, and then liquid crystal is injected for packaging. LCOS puts the control circuit behind the display device, which can improve the light transmittance, thus achieving greater light output and higher resolution.
35 mm slide projector: This technology is one of the most common projection methods to display a single image. Like other portable film projection methods, slides can be played continuously, and the output brightness of the projector is also very high (from 1000-6000 lumens), which can project perfect picture details and rich colors.
Overhead projection
In commercial and educational applications, overhead projector is also a common projection method, which is flexible to install and simple to use. The brightness output is as high as 3000 lumens, and speakers can be used according to their own preferences.
3d projection
Three-dimensional projection technology is realized by polarization of light. Stereoscopic projection requires a high degree of polarization of the screen and a high gain of the screen, and some front projection will also affect the polarization effect. In some special video projection applications, due to the influence of ambient light, relatively high contrast is needed, so it is best to use curved projection screens in such applications.
Second, the ambient light
Ambient light is one of the key links in projection application. After choosing a projector, it is necessary to know whether the ambient light can be controlled ideally in the projection environment. Only by controlling the light well can we ensure that the light in the projection room can be adjusted at any time as needed, and the ambient light can be increased or decreased at an appropriate time, so that the projected image will not be affected by uncontrollable changes in light. Some rooms will have some uncontrollable light, so we need to determine whether these light will directly hit the screen and have an impact on the projected image. In short, users should have a clear understanding of all the light in the projection environment to ensure that the whole projection effect is under control.
Third, the brightness of the display device.
Use the following formula to calculate the brightness of the display device.
IV. Room Settings/Size
Firstly, it is determined whether the shape between the two sides of the audience seat and the screen is narrow and long trapezoid (Figure 1) or rectangular (the viewing angle between the two sides of the seat and the center of the screen in Figure 2 is greater than 30 degrees). If the shape of the room is the type shown in Figure 2, and the viewing angle between the audience and the projection screen is greater than 30 degrees, curtain materials with wide viewing angle should be selected.
Five, the projection image requirements
Traditional video images, such images are usually not very strict with details, and resolution is not the most important factor.
Continuous tone image: This is the most common slide show method, which provides the best image quality in terms of clarity and color reproduction.
Digital or pixelated data with fine details (that is, texture information used in LCD and DLP video projection devices) requires high resolution in order to project high-definition image characters.
Six, the projector and the position of the screen center horizontal line
When the projector and the audience are on opposite sides of the horizontal line in the center of the screen, the screen gain is required to be high, and the reflective screen should be adopted (as shown in figure 1). When the projector and the audience are located in the same direction of the horizontal line in the center of the screen (as shown in Figure 2), the gain requirement is high, and it is recommended to use a retro-reflective screen.
Seven, screen maintenance
See if the screen surface will get dirty or damaged due to unintentional or frequent operation. The typical situation is as follows: in places with large traffic, people may accidentally touch the screen surface; In public places or educational environments, it is impossible for users to carefully protect the screen at any time; Where there are suspended particles or dust problems, the screen may be dirty.