Based on the ultrasonic guided wave technique and the dispersive waveform prediction method, a method about how to image defects in pipes is presented.

在导波传播理论和频散波形预测理论的基础上，研究了超声导波在检测管道时，如何利用时域波形重构缺陷图像的问题。

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The image transmission wasn't perfect and suffered defects because the Earth's atmosphere caused errors, even when the sky was clear, NASA said.

CNN: STORY HIGHLIGHTS