Fig.2 (IMAGE) Osaka University Caption Fourier transforms of the pulse wave and periodic pulse train Credit Non-contact imaging of subsurface defects using a scanning laser source, T. Hayashi, N. Mori, and T. Ueno, Ultrasonics 2021 Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.