颜色失真二维彩色条形码的自适应阈值机读法

采用紫外辐照加速老化方法研究纸基彩色条形码的褪色规律。基于CIELAB模型分析紫外辐照累计时间与二维条形码色差的关系，对4色打印标签的检测结果表明：品红色褪变速率较大，青色、黄色和黑色的褪变速率逐次减小。基于RGB三基色直方图和概率统计原理，提出能有效校正颜色失真、正确机读二维条形码的“自适应阈值法”。实验表明：对于紫外25h加速老化后的褪色条形码，“自适应阈值法”的机读误码率≤0.05%。该研究结果为褪色彩色条形码标签进入实用阶段提供了实验依据。

Machine-read method for faded 2-D color barcodes using self-adaptive threshold

The fading law of 2-D paper-based color barcodes is analyzed with the ultraviolet aging test. The relation between the accumulative ultraviolet irradiation time and the chromatic aberration of 2-D color barcodes is analyzed based on the CIELAB model. The detection results of four-color printed label show that the fading velocity of fuchsine is faster than cyan, yellow and black. A self-adaptive threshold method, which can correct color aberration effectively and can machine-read the 2-D barcodes correctly, is put forward based on RGB trichromatic histogram and the principle of probability statistics. The experiment indicates that the machineread bit error rate of the self-adaptive threshold method is less then 0.05%, which was acquired from 25 h ultraviolet aging test of barcodes. The result provides a criterion for the service period of the color barcodes.