边缘梯度协方差引导的甲骨文字修复算法  

Edge gradient covariance guided restoration for oracle bone characters

作　　者：宋传鸣[1,2] 乔明泽 洪飏 SONG Chuanming;QIAO Mingze;HONG Yang(School of Computer and Information Technology,Liaoning Normal University,Dalian 116081,China;Provincial Key Laboratory for Computer Information Processing Technology,Soochow University,Suzhou 215006,China;School of Chinese Language and Literature,Liaoning Normal University,Dalian 116081,China)

机构地区：[1]辽宁师范大学计算机与信息技术学院,辽宁大连116081 [2]苏州大学江苏省计算机信息处理技术重点实验室,江苏苏州215006 [3]辽宁师范大学文学院,辽宁大连116081

出　　处：《辽宁师范大学学报（自然科学版）》2023年第2期194-207,共14页Journal of Liaoning Normal University:Natural Science Edition

基　　金：国家社会科学基金资助冷门绝学研究专项项目(19VJX112);教育部人文社会科学研究一般项目(21YJAZH075);辽宁省社会科学规划基金资助项目(L19BYY005);复旦大学“古文字与中华文明传承发展工程”规划项目(G3020)。

摘　　要：针对现有甲骨卜辞文字修复方法无法有效处理甲骨文字边缘的突起状毛刺、锯齿效应和笔划断裂等不足,提出一种边缘梯度协方差引导的甲骨文字修复算法.首先,将待处理的甲骨拓片图像进行对比度增强、形态学操作和连通域分析,提取出甲骨文字的候选修复区域;其次,利用边缘梯度的自相关矩阵计算文字边缘的局部曲率和灰度变化率,将其划分为平滑区域和笔划拐点/角点区域;最后,采用线性插值方法重构平滑区域,而利用局部梯度协方差和最小均方误差法计算最优的线性插值权重,实现拐点/角点区域的边缘定向插值重构.实验结果表明,该算法能够保持甲骨卜辞文字的原始字形特点,抑制字迹断裂、突起状毛刺、边缘锯齿效应和边缘特征退化的现象,获得边缘质量较高的甲骨文字.An edge-gradient covariance-guided oracle character restoration algorithm was proposed to address the shortcomings of the state-of-art oracle bone inscription restoration methods that cannot effectively deal with the protruding burrs,jagged effects,and small-scale fractures at the edges of the oracle bone characters.First,the oracle bone topography images to be processed were subjected to contrast enhancement,morphological manipulation,and connected regions analysis.The candidate restoration regions of the oracle bone inscriptions were thus extracted.Subsequently,the local curvature and grayscale’s change rate of the character edges were computed using the autocorrelation matrix of edge gradients.By this way,the edges of the oracle bone characters were divided into smooth regions and stroke inflection/corner point regions.Finally,the linear interpolation method was used to reconstruct the smooth regions of the character edges.Meanwhile,the local gradient covariance and minimum mean squared error method was employed to calculate the optimal linear interpolation weights,which were applied to the edge-directed interpolation of stroke inflection/corner point regions.Experimental results illustrate that the proposed algorithm can maintain the original glyph characteristics of the oracle bone rubbings,and suppress the phenomena of character breakages,protruding burrs,jagged effects as well as the degradation of edge features.Hence,our algorithm obtains oracle bone characters with high quality of edges.

关 键 词：图像修复 甲骨文字修复 边缘梯度协方差 边缘定向插值 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]