锁相红外检测中相位检测方法

介绍了调制加热阶段的一维热波导热方程。为了减少图像序列采集数量,针对相位法红外热成像检测提出了获取热波信号相位信息的方法,即相关检测算法。利用噪声信号与参考信号不相关的原理,有效地提取微弱被测信号。通过对同一组图像序列的处理,将其与4点平均算法比较,证实该算法采集信息少,具有较高检测精度。同时也验证了相位信息对样品表面非均匀性不敏感,使得相位法红外热像技术在无损检测中有广泛应用。

Study of Phase Detection in Lock-in Thermography Nondestructive Testing

One-dimensional heat conduction equation of thermal wave during modulated heating was described.A method,correlation algorithm,was promoted to detect phase information in lock-in thermography nondestructive testing in order to reduce sample images.Using the principle of the reference signal being uncorrelated to the measured signal,the latter could be extracted easily.Compared with averaging four-point algorithm,correlation algorithm was shown to have better precision and need less information.The experimen...