中文摘要：

二维条码通常贴于物体外表面，特别是纸质条码，容易出现污渍或破损的情况，这就需要在识别条码内容的同时能够纠错。PDF417条码常使用的是R—S错误纠正码，纠错级别越高，纠错能力就越强，但是计算量增大，大大影响了识别速度。为了降低R—S纠错等级，提高译码的效率和准确率，文中从图像的预处理人手，将数字图像形态学中的膨胀处理和腐蚀处理结合PDF417码的结构特征设计了一种清除噪声、恢复破损图像的方法，去除条码中的划痕污染，使得条码图形基本复原，再进行解码，可以大大提高译码的速度和识别率。

英文摘要：

Two dimensional bar code is usually affixed to the outer surface of the object, especially a paper bar code,particularly prone to stains or in case of breakage, which requires the identification code and error correction. PDF417 bar code commonly used is the R-S error code, error correction level is higher, the error correction capability is stronger, but the count quantity increases, greatly affects the re.c. ognition speed. In order to reduce the R-S error level and improve the decoding efficiency and accuracy, from the image preprocessing of digital image,morphological dilation and corrosion treatment combined with PDF417 code structure characteristics design a method of noise removal and restoring damaged image, removing the bar scratches pollution for the bar code graphics basic restoration, then decoding, can greatly improve the decoding speed and recognition rate.