Design And Research Of Large-scale Screen LED Control Systems

LED display screen is a kind of large-scale display systems, which is composed of Light Emitting Diode lattice modules. This display system can dynamically display text, image, and other information. Because of its rapid response, high brightness, long lifetime, strong environment adaptability, LED display screen is used widely in a great many fields like finance, transportation, advertising and so on.At present, in most asynchronous display screen controllers design, the mainstream is 8-bits or 16-bits microprocessor, which involves some limitations in operation speed, memory capacity, communication capability, etc. To solve these problems, a asynchronous chromatic LED display screen control system with high storage efficiency and various communication modes is designed in this paper based on former researches. The main contributions of the thesis as follows:Firstly, combining the high-performance microprocessor ARM with the Programmable Logic Device to design the main controller of LED display screen. Various dynamic display effects of chromatic images are realized. At the same time, the development of Ethernet communication and wireless communication is helpful to remote control and maintenance.Secondly, concerning the necessity of abundant gray in chromatic images, the Programmable Logic Device is adopted to design the display screen's driver logic circuit. For different bit-plane data, different pulse widths are modulated using 1/16 line scanning method. Then, the image's color information is reproduced.Thirdly, because of limited storage capacity and lower processing capability in LED display controller, the Integer Wavelet Transform image coding method is proposed to reduce the computational complexity of image compression. In addition, the improved RLE in accordance with the wavelet transformed image characteristic is used for compression coding. Better compression effect is achieved and storage space is saved.At last, we conclude the dissertation and point out the subjects of future research.