Abstract: The characteristics of ultrasonic probe restrict the performance of the non-destructive inspection system. The characteristics of acoustic field is focused in this paper. Firstly, the characteristic parameter system of acoustic field is constructed. Secondly, acoustic field is visualized through scanning spherical target. Thirdly, near field length, aperture size and off-axis angle of acoustic field are worked out after image process such as preprocessing, binaryzation, boundary detection and characteristic extraction. Then, how to apply the measured characteristics of probe acoustic field in non-destructive inspection is discussed. Finally, some measurement experiments indicate the validity of the proposed method.

Key words: ultrasonic probe, C-scan image, characteristic of acoustic field, image processing