Design And Development Of Interactive LED Display System

The emergence of human-screen interactive technology stems from the continuous improvement of people's demand for visual experience.People are no longer satisfied with the unidirectional visual image capture,but hope to interact with the display screen in a variety of novel and natural ways.At present,most of the human-screen interaction used on LED display in the market depends on scanning of surface acoustic wave or light,or image recognition to detect interaction.These human-screen interaction modes are limited in detection distance,inaccurate detection positioning,or vulnerable to environmental light.Therefore,they are mostly used in the interaction of small-size indoor displays.For outdoor large-size LED display screen,there are still limitations in its application.In view of the above problems,this project aims to study a new interactive method of LED display screen with wide detection range,strong environmental adaptability and accurate positioning.Based on a comprehensive investigation and comparison of various human-screen interaction methods at home and abroad,this paper designs and develops an interactive LED display system based on capacitive proximity sensing,which can be used for human-screen interaction detection on outdoor large-scale LED display.The main work of this paper is as follows:(1)An interactive method of LED display screen based on capacitive proximity sensor is proposed.According to the self-capacitance sensing technology of proximity sensor and the capacitance conversion principle,a distributed embedded structure of proximity sensor on the surface of the LED display screen is designed to detect the proximity or touch behavior at any position on the display screen.Meanwhile,according to the actual needs of the system,the proximity sensor's sensing mode selection and state execution strategy are proposed to make the interactive system adapt to more applications.(2)The overall structure framework of the interactivesystem is constructed.The hardware architecture of system sensing detection,data processing and data transmission control is designed,and the communication rules of the system data communication network are formulated.The human-screen interactive function is realized together with the system control software written independently.(3)Aiming at the noise interference caused by the capacitance proximity sensor in the circuit of LED display,and the induction error trigger caused by the sensor's capacitance offset from ambient temperature,an adaptive base-value synthetic filtering algorithm is proposed.In the sensor data processing stage,the detection signal is filtered by median filter and first-order lag filter with variable parameters,and the signal noise is filtered in real time.At the same time,the basic value of the sensor counting signal is adjusted automatically under different temperature environments to eliminate the capacitance offset caused by the temperature change in the process of use.The experimental results show that the proposed algorithm is effective.(4)According to the overall technical scheme,filtering algorithm and data transmission communication rules of the interactive system,a set of upper computer operation software suitable for the interactive LED display screen in this paper is developed.Firstly,the overall working platform of the interactive system is built independently.Secondly,based on the platform,the method and process of establishing the interactive mapping with the LED screen on the computer are analyzed,and a variety of monitoring and control functions are provided to facilitate the management and maintenance of the interactive system.Finally,the practical cases of the interactive system designed and developed in this paper are introduced in different applications.The interactive LED display system based on capacitive proximity sensor can accurately detect the user's touch or stamp behavior on any size of LED display,thus triggering the effect of real-time interactive response in the corresponding position of the display screen.The interactive system provides five scanning resolutions in two induction modes to meet theneeds of LED display in different occasions.At the same time,the internal adjustment algorithm ensures the normal operation of LED display in high and low temperature environment,and improves the stability and environmental adaptability of the system.