中文摘要：

针对超声衍射时差法（TOFD）的近表面检测盲区问题，提出一种基于直通波幅度分布分析的近表面缺陷检测方法。在近表面缺陷检测信号的直通波部分选取多个关键点，揭示了各关键点幅度分布与近表面缺陷深度的关系，获得了用于近表面缺陷检测的幅度分布特征值。试验结果表明，该方法能准确检测出埋深1．0mm的人工缺陷，有效地提高了对近表面缺陷的识别能力。

英文摘要：

To solve the rather low diffraction method, a near-surface defect recognition capability of near surface defect in ultrasonic time of flight detection method based on the through wave amplitude distribution analysis is proposed. Several key points in the part of through wave of testing signal are extracted and relationship between the amplitude distribution of key points and depth of near-surface defect is analyzed. The characteristic numbers of amplitude distribution which can be used to test near-surface defect is obtained. The experimental results showed that this technique could accurately detect the artificial defects with buried depth of 1. Omm, and the recognition ability to near-surface defect was effectively improved.