Fig. 1. Schematic diagram of binary search

Fig. 2. Schematic diagram of wavelet transform

Fig. 3. Time domain signal diagram. (a) Measured ultrasonic signal; (b) Ultrasonic signal after wavelet transform

Fig. 4. Signal processing result diagram. (a) Wavelet transform result of a priori experiment; (b) Reconstructed signal containing defect reflection signal

Fig. 5. Schematic diagram of numerical simulation structure

Fig. 6. Signal processing result diagram. (a) Simulation result difference diagram; (b) Compressed sensing recognition signal result diagram

Fig. 7. Simulated binary search result diagram. (a) Binary search schematic diagram; (b) Curve fitting result diagram

Fig. 8. Detection system diagram. (a) Detection system schematic diagram; (b) Detection system device diagram

Fig. 9. Schematic diagram of defect search settings

Fig. 10. Experimental results. (a), (c), (e) show that the preset area is on the left, in the middle (including defects) and on the right; (b), (d), (f) is the corresponding curve fitting diagram

Fig. 11. B-sweep results with 1 mm scanning step

Fig. 12. B-sweep results with 0.1 mm scanning step