Abstract: Direct Part Marking（DPM） is a process to mark parts permanently with product information including serial numbers, part numbers, date codes, and barcodes. This is done to allow the tracking of parts through the full life cycle. However, obtaining a high quality barcode image on metal surface is especially challenging due to the high reflective property of metal. Many barcodes are difficult to be read successfully because of the strong specular reflection. To solve this problem, this paper proposes a five-step-reconstruction model to restore the information in the highlight area. First, slant correction is carried out by orientating the “L finder pattern” right on the lower-left corner of the image. Then, each Data Matrix barcode module is located by mesh generation. Third, the highlight area is found by the Modified Specular-Free（MSF） image. Finally, the lost information in the highlight area is reconstructed by the proposed five-step-reconstruction model. The verification experiment shows that this algorithm can remove the highlight area reliably and make more Data Matrix symbols be read more easily.

Key words: direct part marking, metal surface, Data Matrix barcode, local specular, reconstruction

摘要： 为实现工业产品的可追溯性，直接将条码加工在零件表面的直接零件标识（Direct Part Marking，DPM）技术，在国内外受到了越来越多的关注。对于金属零件，由于其具有较高的反光性，由相机捕获的金属表面的条码图像常常产生局部高光现象，影响条码的正确读取。为此，针对金属表面激光标刻二维条码出现的局部高光现象，提出了基于五步重构模型的条码重构法，以重构高光区域的条码信息。对获得的条码图像进行倾斜校正，使“L”型实线边界位于图像左下角，对条码进行网格划分实现各个模块的定位。基于Modified Specular-Free（MSF）图像对高光区域进行检测。采用五步重构模型对条码的各个模块进行数值填充，对条码进行读取。实验表明，该算法能达到去除金属表面上条码局部高光的目的，并取得了较高的识读正确率。

关键词: 直接零件标识, 金属表面, Data Matrix条码, 局部高光, 重构