摘要
计算机分层成像对板状构件的无损检测有其独特的优势,但由于投影角度有限,导致重建图像存在有限角伪影和分层图像模糊。为提高计算机分层成像图像质量,提出了基于投影视角加权的滤波反投影算法,有效抑制了高密度特征对其它层的干扰现象。首先,根据不同投影视角分层图像间的不相似度,确定不同投影视角的加权系数;而后,对投影进行加权反投影重建;最后,分析了3种不同加权系数对重建图像质量的影响,同时引入层灵敏度曲线的调制度作为定量评价指标,未加权和3种不同加权系数层灵敏度曲线的调制度依次为0.082,0.267,0.290,0.294。实验结果表明,该算法减少了分层图像混叠,层灵敏度曲线的调制度提升了约0.2,重建图像质量显著提升。
Computed laminography imaging has its unique advantages in nondestructive testing of plate components.However,due to the limited projection angle,there are limited-angle artifacts and blur in the sliced image.In order to improve the image quality of computed laminography,a filtered back-projection algorithm based on projection view-weighting is proposed,which effectively suppresses the interference of high-density features to other slices.Firstly,according to the dissimilarity among the sliced images from different projection views,the weighting coefficients of different projection views are determined,and then the projection is reconstructed by weighted back-projection.Finally,the effects of three different weighting coefficients on the quality of reconstructed images are analyzed,and this paper takes the modulation of slice sensitivity profile as the quantitative evaluation index,the modulation of slice sensitivity profiles for unweighted and three different weighting coefficients are 0.082,0.267,0.290 and 0.294,respectively.The experiment results show that the proposed algorithm reduces the sliced image aliasing,the modulation of slice sensitivity profile is increased by about 0.2 and the quality of reconstructed images is significantly improved.
作者
蔡玉芳
李屏懿
王珏
王涵
Cai Yufang;Li Pingyi;Wang Jue;Wang Han(Key Laboratory of Optoelectronic Technology and Systems of the Ministry of Education,Chongqing University,Chongqing 400044,China;Engineering Research Center of Industrial Computed Tomography Nondestructive Testing of the Ministry of Education,Chongqing University,Chongqing 400044,China)
出处
《仪器仪表学报》
CSCD
北大核心
2021年第6期64-74,共11页
Chinese Journal of Scientific Instrument
基金
国家科技重大专项(2017-VII-0011-0106)资助。
关键词
计算机分层成像
直线CL
投影视角加权
滤波反投影
板状构件
computed laminography
linear CL
projection view-weighting
filtered back-projection
plate component
