Two large LED screen on the video signal processing method
The large LED display is a digital flat panel displays. This requires that it can display text, graphics, animation, images, video programs and other information. Full-color LED display screen's purpose is to create a giant color display. The large LED display screen and plasma display, large screen rear projection and flat panel displays have many similarities.
In contrast, the LED in the distribution of the information, the driver, reducing power consumption, improve efficiency, and reduction of color and consistency of the difficulty may be larger than other flat panel displays. This is because the light emitting diode is anger devices, the switching time is in nanoseconds, memory function, coupled with its large display area, the signal transmission distance is long, you can not use the most advanced COG, SOB and other large-scale integrated circuit manufacturing method, the following briefly introduce the LED display on the image signal processing.
LED display screen image signal processing in general there are two ways:
One way is using a dedicated large-screen signal processors, interlaced television signals processed into progressive scan signals, and then played on the big screen. The high-performance processing function of the number of bits up to 10 yuan, the interpolation operator in to do the scan conversion, motion estimation and compensation, as well as scan conversion. High-end large-scale LED screen using this method, and image signal processing, try to turn the signal raised to the broadcast, of course, the results would be better. The computer image is also subject to deal with this processor, and then sent to the large screen display. Processing technology continues to develop many new algorithms have been proposed. We are familiar with the large-size rear-projection and plasma screen TV are widely using this method, the effect is much better than regular TV. In this case, the output signal is usually transformed signal format to describe, it is more precise.
Another method is a multimedia approach, often referred to as synchronized screen method, which use ordinary multimedia card to capture TV signals and demodulation, filtering and sound separation. The image signal after A / D conversion, MPEG encoding compression to store. Playback and then decompress directly viewed on a computer monitor. The signal sent to the big screen through a dedicated interface card from the computer's DVI interface or graphics, but also some processing on the adapter. At this time, the big screen is actually equivalent to a part of the computer monitor or on, often referred to as Windows, you can achieve one to one synchronization. The computer monitor is progressive scan, so if the send significant signals for pumping frame drawn line processing, then the large-screen display format is the format of the monitor.
For example, the VGA format is the number of pixels to 640x480 progressive scan format, scan update rate of 75Hz. But the 75Hz progressive scan signal, not the image source to enhance the image quality did not improve, but also badly in fact higher than the standard 50Hz interlaced, similar to the effect of the DVD or VCD, which is often confused places. For some screen picture swap, for example, even the screen information discard only display the odd screen information sent, the effect is of course even worse. Mentioned in passing that the non-imaging program is relatively simple, although some games animation also requires good continuity, but for the animation to play on the big screen, the frame rate of more than 10Hz can accept.
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The embedded controller or microprocessor controlled display screen, the program generated by the controller, the controller processing capacity constraints, the screen fast enough, will cause the screen is not continuous. The most typical phenomenon is controlled by microcomputer screen, the text left or right, not smooth, but jumping style. Experience and calculations can be obtained, a bar screen 10 16XI6 dot matrix Chinese character, full screen to the speed of 5 seconds left, in order to move the smooth continuity, the frame frequency must be above 15Hz.
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