超声相控阵低信噪比背景下相关相位校正  

Phase aberration correction in poor SNR environment for ultrasonic phased array

作　　者：杨平[1] 陈斌[1] 施克仁[1] 

机构地区：[1]清华大学机械工程系无损检测工程中心,北京100084

出　　处：《清华大学学报（自然科学版）》2006年第8期1353-1356,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家教育振兴计划资助项目(081100501)

摘　　要：超声相控阵中,相位校正在消除相位畸变中起着重要作用。部分相控阵探头,阵元的面积小,回波信号弱,信噪比差。针对该问题,首先研究了邻近和集总相关估计在不同信噪比情况下的校正性能:发现信噪比SNR>12 dB时,邻近相关估计基本不产生估计误差;SNR<5 dB时,邻近相关估计产生的误差随着信噪比下降急剧增大。而集总相关即使在噪声强度较小时也不能做到估计误差为0;在噪声强度增大的过程中,其估计误差并未急剧增加,这与邻近相关估计不同。根据邻近和集总相关的特点,提出了混合相关校正结构。实验表明,混合相关充分利用了邻近和集总相关估计的优点,显著提高了图像质量。Phase aberration correction can cancel phase aberration in ultrasonic phased array. In practice, some arrays suffer from small element, weak signal and poor signal-to-noise ratio. The correction abilities of the neighboring and sum-up＇correlations were studied with various background noise amplitudes. Errors created by the neighboring correlation estimates are almost zero for SNR above 12 dB, but the errors increase dramatically for SNR below 5 dB. The error created by the sum-up correlation estimate is not zero even if the SNR is very high but the error does not increase significantly as the SNR decreases. A combined correction architecture was then developed for phased array that provides better even correction than other architectures.

关 键 词：无损探伤 超声相控阵 相位校正 互相关 信噪比 

分 类 号：TG115.28[金属学及工艺—物理冶金]