LED显示屏γ校正的研究和实现

Research and Implementation of γ Correction of LED Display Screen

针对因CRT与LED的光电特性差异造成LED显示屏灰度畸变的问题,从基于人眼视觉特性方面,分析了视觉灵敏度特性和亮度变化关系。针对LED发光特性,提出了对LED显示屏的γ校正要分为二步进行,即适合于LED光电特性和视觉亮度特性的校正公式。给出了一种基于查找表的γ校正的设计方法,介绍了γ校正系统构成,阐述了γ校正过程,设计了在FPGA内部γ校正功能的实现方法,在FPGA内部生成内嵌ROM,替代了外挂集成芯片的功能,简化了电路,并在Quartus Ⅱ下进行了仿真。理论和实践的结果表明,采用这种校正方法使LED显示屏的图像效果更佳。

To the gray scale distortion of LED display screen resulted from the difference between optical and electrical property of CRT and that of LED,the relation between visual sensitivity and luminance variation was analyzed based on human visual characteristics.It was proposed that γ correction of LED display screen should be divided into two-step,namely the gray scale correction formula which is suitable for photo-electrical characteristics of LED and for visual brightness characteristics.One design method of γ correction was presented based on look-up table.The composition of γ correction system and the γ correction process was described,and the realization method of γ correction inside FPGA is designed.The internal ROM within FPGA can replace the external integrated chip for simplifying the circuit.Simulation was made under Quartus II.The result showed that this correction method can get better image display effect for LED.