Research On Local Dimming Algorithm Of Liquid Crystal Display

Straight down LED backlight module is widely used to provide light source for LCD.At present,most LED backlight modules use constant control of output brightness,that is,all LED lamps in the LED backlight module maintain the brightness of the same value,which leads to unnecessary and high energy waste,and light leakage for the display of dark areas in the image,which affects the display quality of LCD.Although some scholars at home and abroad have proposed some local dynamic dimming technologies,there is still much room for improvement in reducing energy consumption and improving display quality.In order to reasonably reduce the energy consumption of LCD and improve the display quality,a new local dynamic dimming technology is proposed in this paper.The main research contents are as follows:(1)By comprehensively analyzing and comparing the advantages and disadvantages of typical local dynamic dimming algorithms,this paper designed a new local dynamic dimming algorithm based on the existing algorithms.The new algorithm used the maximum principle to obtain the gray image of the input image,and then used the idea of error correction on the basis of Otsu method and maximum entropy method to obtain the brightness value of LED backlight,and improved the BMA backlight smoothing algorithm by introducing bilinear interpolation algorithm,The dimming image was obtained by using the pixel compensation algorithm based on logarithm.The dimming algorithm and other dimming algorithms proposed in this paper were simulated and analyzed on the MATLAB platform.It was found that the dimming algorithm can effectively improve the display quality.(2)Aiming at the problem that the simulation speed of local dynamic dimming algorithm was slow on MATLAB platform,this paper used C+ + language to simulate and develop the seven traditional local dynamic dimming algorithms and new local dynamic dimming algorithms involved above based on QT platform,and then developed a set of local dynamic dimming algorithm simulation software for the image processing effect of different local dynamic dimming algorithms,It could facilitate users to analyze the image processing effect of various common algorithms without running matlab platform,which bringed great convenience.(3)Aiming at the problem of how to accurately analyze the performance of local dynamic dimming algorithm,this paper designed a set of evaluation model of local dynamic dimming algorithm based on entropy weight method,taked energy-saving rate,overflow rate and contrast as objective evaluation indexes,and analyzed the image display quality applied to different local dynamic dimming algorithms from the perspective of subjective and objective combination for four typical images,which proved the effectiveness of the algorithm proposed in this paper.(4)This paper developed a set of software and hardware design scheme of automobile liquid crystal instrument based on FPGA,designed the hardware circuits such as LED backlight module and control circuit module,and designed the software of each module of local dynamic dimming algorithm.Finally,the display effect comparison diagram of automobile liquid crystal instrument using global constant backlight and local dynamic dimming was introduced,which verified the superiority of local dynamic dimming technology.