摘要
跨座式轨道梁表面出现的裂纹和缺陷,严重影响了列车安全及平稳运行。由于采集的图像存在边缘模糊、局部或整体对比度差等不足,提出一种基于曲波变换的梁面裂纹增强新算法。根据裂纹图像曲波变换后的不同尺度系数,由于分数阶微分能增强信号的中频成分、非线性保留信号低频的特点,在曲波域的低频采用分数阶微分增强纹理信息;同时在曲波域的方向子带根据方向的敏感性,采用对弱边缘增强、强边缘保留、噪声去除的处理。并对低频和方向子带增强时的参数分别进行了讨论。实验结果表明,所提出的方法与其他算法相比,主观上细节增强和对比度提高均优于其他算法,客观上对比度改善指数(con-trast improvement index,CII)也大大提高,表明提出的算法增强效果良好。
The surface of prestressed concrete（PC）beam has been covered with cracks and other flaws,which is harmful to the safety of system. As the images collected have different shortcomings such as edge blurring,poor contrast,etc. A new algorithm of crack enhancement of straddle-type monorail track beam surface based on curvelet transformation is presented. It is accord- ing to the different scale coefficients of curvelet domain,the fractional differentiation can enhance the mid-frequency compo- nent and retain the low frequency component nonlinearly,then the coarse scale coefficients of curvelet domain is enhanced by the fractional differentiation; at the same time,according to the direction sensitivity of fine scale coefficients of curvelet do- main ,an operator is proposed that the weak edge is enhanced nonlinearly,strong edge is retained,and noise is removed. Differ- ent fractional operator in low-pass subband and regulation parameter in high-pass subband is discussed and gotten appropriate range separately. Experimental results show that the method proposed in this paper has greatly improved visual effects and con- trast improve index （CII） as compared with other methods,and the enhancement effect is good.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2012年第12期2754-2760,共7页
Chinese Journal of Scientific Instrument
基金
国家科技支撑计划资助课题(2007BAG06B06)
关键词
裂纹增强
曲波变换
分数阶微分
局部统计
crack enhancement
curvelet transform
fractional differentiation
local statistics
