Enhancement of ultrasonic B-scan images.

摘要

An ultrasonic B-scan is a useful method to display the result of a material inspection. In order to improve the lateral resolution and signal-to-noise ratio of a B-scan image, Synthetic Aperture Focusing Technique (SAFT) has been used by several researchers. In this thesis, it was intended to improve the resolution of a B-scan image by implementing deconvolution before the SAFT process. In conventional deconvolution, a single signal is used as a reference for processing all ultrasonic echoes, although this might not lead to best possible enhancement of the B-scan image. By contrast, it was shown in this work that using a reference library of ultrasonic signals for deconvolution would result in a B-scan with considerably better resolution. To obtain such a reference library, we developed a mathematical model of the pulser transducer, which emits ultrasonic wave into the material.