全彩LED大屏幕视频图像信号的校正

A CORRECTION OF VIDEO IMAGE SIGNAL FOR THE LED SUPER SCALE COLOR SCREEN

全彩ＬＥＤ大屏幕可以用来显示电视画面。由于ＣＲＴ发光特性的非线性，在图像信号源处引入一种称为γ校正的相反预失真来补偿ＣＲＴ的这种非线性。但由于全彩ＬＥＤ 大屏幕系统的发光特性与ＣＲＴ的发光特性不同，它的发光亮度与其控制量成线性关系，因此在显示电视画面时会引起严重的灰度畸变，观赏性极差。因此必须在把控制信号送给ＬＥＤ 驱动电路之前对其进行校正，使之适合ＬＥＤ屏的显示。此外，还考虑到人的视觉的明亮度与物理亮度的关系。本文给出了一种对ＬＥＤ大屏幕信号进行校正的方法，即γ′校正，实验结果表明效果极其显著。

LED super scale color screen can be used to show TV programs. Since the luminescence character of CRT is nonlinear,a contrary pre distortion called γ correction is given at the source of image to compensate the nonlinearity. But as the significant difference between the luminescence property of LED and that of CRT,there exists great grey deformity and the outlook is terrible when LED color screen shows TV programms,so the signal must be corrected before driving the LED.In addition,considering the relationship between the brightness of poeple's sight feeling and the physical brightness,this paper gives a way of correcting sigal for LED color screen called γ′ correction. Experiment results show the effectiveness of the method is significant.