中文摘要：

常规矢量全聚焦成像仅利用检测信号的幅值信息,其成像质量受噪声、栅瓣和旁瓣等的影响大。综合利用检测信号的幅值和相位信息,本文提出两种相位加权的矢量全聚焦成像方法。首先,对全矩阵数据的相位信息进行分析,提取出两种相位特征参数：相位一致因子（Phase Coherence Factor：PCF）和极性一致因子（Sign Coherence Factor：SCF）;然后,将全阵列划分为若干子阵列,分别利用两种相位特征参数对各个子阵列的成像幅值进行加权,求取加权幅值特征向量;最后,对所有子阵列的加权特征向量进行合成,得到两种加权的矢量全聚焦成像,并从中提取出裂纹方向及尺寸等特征信息。将三种矢量全聚焦成像方法应用于不同缺陷检测仿真及实验验证,结果表明,3种方法均可以实现缺陷方向识别与长度定量测量;但相位加权矢量全聚焦成像效果明显优于常规矢量全聚焦成像结果,其成像信噪比及分辨率更高,缺陷角度及长度测量结果更准确。本文研究工作为缺陷无损评价提供了可行的技术手段。

英文摘要：

The conventional vector total focusing method only uses the signal amplitude information, resulting in the imaging quality very affected by the noise, grating lobes, side lobes and so on. In this paper, the signal amplitude and phase information are used together, and then puts forward two kinds of phase weighting vector total focusing method. First , It is based on an analysis of the phase information at the full matrix data, two phase feature parameters, namely the phase coherence factor （PCF） and the sign coherence factor （SCF） are proposed; Then, the whole array is divided into a number of sub-arrays, using the two phase feature parameters to weight the imaging amplitude and consequently to get the weighted amplitude feature vector; finally , compounding the weighted amplitude feature vector of all sub- arrays, the new method for characterizing reflectors is presented, that is phase weighting vector total focusing method. In the simulation and experiment, above three kinds of vector total focusing methods was applied to defects detection. It turned out that the three methods can all achieve direction recognition and length quantitative measurement of defects, but the phase weighting method results is obviously superior to the conventional method results, the methods obtain improvements in SNR and resolution, and the direction and length measurement of defects are more accurate. The research work for the defect non-destructive evaluation provides a feasible method.