改进的DataMatrix码L形边精确定位方法

深圳大学光电工程学院,广东深圳 518060

信息处理技术; 图像处理; DataMatrix码; L边定位; Hough变换; 直线拟合

An improved method of locating L-edges in DataMatrix codes
LI Dong, GUO Haoming, TIAN Jindong, and TIAN Yong

College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, Guangdong Province, P.R.China

information processing technology; image processing; DataMatrix code; L feature edge locating; Hough transform; line fitting

DOI: 10.3724/SP.J.1249.2018.02151

备注

传统DataMatrix(DM)码的定位方法依赖经Hough变换域中的极大值点来定位DM码的L形特征边.为提高定位的鲁棒性,提出一种特征边精确定位方法,包括4部分:基于角点分布的DM码候选区域快速定位和优先级排序; DM码候选区外轮廓提取,减少非感兴趣边缘对定位产生的干扰; 改进Hough变换初定位L边,快速进行直线投票; 迭代加权最小二乘法直线拟合,精确定位L边.此方法在TMS320DM648平台下以主频864 MHz运行,对图像分辨率为640×480的含DM码图片,单条码平均识别时间为64 ms,识别率达到99.9%.实验结果表明,该方法能稳定准确快速实现DM码定位,满足工业现场使用需求.

The traditional localization method based on DataMatrix(DM)code uses the maximum point in the Hough transform domain to locate the ‘L' shaped edge of DM code. In order to improve the robustness of locating, a new precise feature edge locating method is proposed, which consists of four parts: ① the fast location and priority ranking of DM code candidate regions based on corner distribution; ② DM code candidate area contour extraction, which reduces the impact of non-interesting edge on the location; ③ the improved Hough transform, which is used to locate the edge; ④ the iterative weighted least squares method for linear fitting, which is used to locate the ‘L' line. This method runs on TMS320DM648 platform with a main frequency of 864 MHz. The average recognition time of single barcode is 64 ms for the DM code with a resolution of 640×480 and the recognition rate is 99.9%. The experimental results show that this method can achieve DM code positioning accurately and fast, and it can meet the industrial requirements.

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