Brightness Consistency Detection And Correction Of LED Display Terminal Based On Machine Vision

Intelligent LED display terminals are more and more widely used in modern society.Especially with the development of modern intelligent transportation,intelligent LED display terminals as media information carriers are receiving more and more attention.It has evolved from a single display of information in the past to a medium for the exchange of information between people and networks.In the field of modem transportation,intelligent LED display terminals have become an indispensable intelligent terminal device in the field of road traffic.People not only use LED display terminals as display of text,images and video,but also a large number of sensors carried by themselves used to collect various environmental information of different road sections.The traffic information of these different sections,congestion information,and even meteorological information such as weather,temperature,and humidity in the area where the terminal is located are uploaded to the intelligent traffic control system.This helps the system optimize traffic management and publish important planning information on the LED display terminal in time.Therefore,the accuracy of the information displayed by the LED display terminal is particularly important.The LED display terminal usually used in the transportation system is composed of a large number of rectangular LED modules,and each rectangular LED module is composed of a plurality of LED pixels,and each LED pixel is usually composed of 2-3 different color LED tubes.Therefore,the brightness change of each LED tube affects the quality of the information displayed by the entire LED display terminal.In the production process of LED tubes,a difference of brightness between 20%and 40%and a difference in chromaticity within 5 nm are allowed between different batches of lamps.The brightness difference between the pixels of the LED module that the human eye can distinguish is 1%-2%,and the chromaticity difference is 1 nm-2nm.In the outdoor use process,as the aging will increase the brightness attenuation and chromaticity drift of the LED tube,these factors will seriously affect the overall brightness of the LED display terminal,which will lead to the "flower screen" phenomenon.In view of the above problems,this paper proposes a brightness consistency correction algorithm based on machine vision for intelligent LED display terminals.The method firstly uses an high-precision camera to capture an image of the smart LED display terminal,and then processes the image information of the captured smart LED display terminal,which mainly uses affine transformation,morphological filtering,single lamp bead positioning,lamp brightness extraction and other methods.After obtaining the brightness information and position information of all the LED lamp beads in the image,the histogram of the brightness distribution of the LED lamp bead in the LED display terminal can be obtained,and the LED brightness histogram is approximately normal distribution under normal conditions.Depending on the brightness of the scene of the LED display terminal used,the optimal brightness value can be selected to achieve an optimal brightness-consistency scheme.Finally,by suppressing the brightness of the high-brightness LED lamp bead,the convergence of the brightness uniformity of the LED display terminal is achieved.For the better convergence scheme,the correction matrix can be sent to the LED control board,and finally the control panel can adjust the brightness consistency of the LED display terminal by PWM modulation.By correcting the brightness consistency of the LED display terminal,the quality of the display information of the LED display terminal can be further improved,and the use time of the LED display terminal can be prolonged.