基于改进Canny算子和Hough变换的表格图像校正方法  

Table Image Correction Method Based on Improved Canny Operator and Hough Transform

作　　者：郝泽兴 郭改枝 HAO Ze-xing;GUO Gai-zhi(College of Computer Science and Technology,Inner Mongolia Normal University,Hohhot 010022,China)

机构地区：[1]内蒙古师范大学计算机科学技术学院,内蒙古呼和浩特010022

出　　处：《内蒙古师范大学学报（自然科学汉文版）》2020年第5期433-441,共9页Journal of Inner Mongolia Normal University(Natural Science Edition)

基　　金：内蒙古自然科学基金资助项目(2020MS06029,2020LH06009);内蒙古自治区科技创新引导基金资助项目(KCBJ2018006);内蒙古自治区关键技术攻关计划资助项目(远程控制地下供水管道漏水监测系统的实现)。

摘　　要：为了校正表格图像提高后续单元格分割和光学字符识别的准确性,将Canny算子和Hough变换应用于表格图像的校正中。针对传统Canny算子对于局部噪声去除效果不理想且易出现误检和漏检的问题对其进行了改进,改进后的Canny算子采用联合双边滤波进行图像平滑,图像梯度和幅值的计算使用3×3模板代替2×2模板并增加了45°和135°方向的计算模板。针对Hough变换倾角计算结果与真实倾角存在部分偏差的问题,在Hough变换所计算出倾角的邻域范围内,利用数学形态学原理对真实倾角进行了迭代计算。实验结果表明,改进的Canny算子可以有效去除图像噪声并保留图像边缘,结合Hough变换和数学形态学的迭代倾角计算方法可以有效提高表格图像的校正效果,具有较强的实用性。To improve the accuracy of subsequent cell segmentation and optical character recognition,Canny operator and Hough transform were applied to the correction of the table image.With regard to unsatisfactory for local noise removal and being prone to misdetection and missed detection of the tradi-tional Canny operator,the improved Canny operator used joint bilateral filtering was applied to smooth the image and the image gradient and amplitude were calculated through 3×3 template to replace the 2×2 template and calculation templates for 45°and 135°directions were added.To overcome the partial deviation between the Hough transform inclination angle calculation result and the true inclination angle,the mathematical morphology principle was used to iteratively calculate the true inclination angle within the neighborhood of the inclination angle calculated by the Hough transform.The results showed that the improved Canny operator effectively removed image noise and preserved image edges.The iterative inclination calculation method combined with Hough transform and mathematical morphology effectively improved the correction effect of table images and was of strong practicability.

关 键 词：HOUGH变换 图像校正 联合双边滤波 数学形态学 CANNY算子 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]