为了克服采集相机渐晕在LED显示屏逐点一致化校正过程中产生的亮度不均匀缺陷, 提出了一种基于LED显示屏本身和若干屏幕离散位置亮度测量的采集相机渐晕校正方法。首先分析了相机对LED显示屏进行数据成像采集过程及成像特征, 在此基础上, 提出了采集相机渐晕的标定方法, 得到了代表相机渐晕的拟合曲面, 从而计算出采集相机上每一像素点的渐晕修正系数。利用上述方法对LED显示屏进行了单箱亮度校正实验。实验结果表明: 单箱校正的显示均匀性从渐晕修正前的6.69%缩小到修正后的1.49%。经过对相机影像渐晕修正以后, 可以完全消除修正前的亮度曲面分布, 从而克服了修正前LED显示屏中心暗、四周亮的缺陷, 达到了理想的多屏拼接校正效果。

In order to overcome the non-uniformity defects of image vignetting captured by camera in dot-to-dot correction on LED display screen, a vignetting correction method based on LED display screen and discrete position luminance measurement was put forward. First, the process of camera image acquisition and imaging features of LED display were analyzed. From this, a correction method of camera vignetting was proposed, a fitting surface of camera vignetting was obtained. Then, a vignetting correction factor matrix corresponding pixels on camera sensor was calculated. Using the above method, an experiment of single-box luminance correction of LED display screen was conducted. Experimental results indicate that the uniformity deviation of LED display screen can be narrowed from 6.69% to 1.49% after image vignetting factor calibration. After correction of camera image vignetting, non-uniformity surface distribution can be completely eliminated. Therefore, the “center-dark, surround-bright” defect on LED display screen is overcome, and the desired correction effect for multi-screens stitching display is achieved.