基于小波变换的相控阵全聚焦图像去噪  

Image Denoising for Phased Array Total Focusing Based on Wavelet Transform

作　　者：杨贵德 陈伟 詹红庆 杜南开 陈振光 YANG Guide;CHEN Wei;ZHAN Hongqing;DU Nankai;CHEN Zhenguang(Key Engineering Technology Research and Development Center of Guangdong Province Ultrasonic Electronics,Shantou 515041,China)

机构地区：[1]广东省超声电子重点工程技术研究开发中心,汕头515041

出　　处：《无损检测》2018年第8期53-56,共4页Nondestructive Testing

摘　　要：针对相控阵全聚焦技术的成像背景噪声问题,提出了一种基于小波变换的相控阵全聚焦图像去噪声方法。利用离散小波变换将全聚焦图像信号分解到小波域,变换后的高频子带系数采取无偏似然估计的自适应阈值处理。对处理完的高、低频子带系数进行小波逆变换,重构全聚焦图像。试验结果表明,该方法能有效去除全聚焦图像的背景噪声,保留被检工件内部的真实缺陷信号。In order to solve the problem of the imaging background noise of the phased array total focusing method,this paper presents a method to eliminate the noise of phased array total focusing method image based on wavelet transform.The focusing image signal is decomposed into wavelet domain by the discrete wavelet transform,and the high frequency sub band transformed coefficients is subjected with adaptive threshold processing based on unbiased risk estimation.Inverse wavelet transform is then implemented on the processed high and low frequency sub band coefficients,and hence total focusing method image is reconstructed.The experimental results show that the proposed method can effectively remove the background noise of the total focusing method image,and retain the real defect signal inside the inspected workpiece.

关 键 词：全聚焦 去噪声 小波变换 子带系数 自适应阈值 

分 类 号：TG115.28[金属学及工艺—物理冶金]