Comparison of ultrasonic imaging algorithms for post processing of laser induced phased array ultrasonic data

Laser ultrasonics (LU) is a non-destructive testing (NDT) method in which ultrasound is created and detected by lasers. This technique gives analysts the ability to inspect objects that would not be possible with conventional ultrasonics methods. Once the full matrix capture (FMC) data is collected, post processing algorithms are used to form an image of the material being examined which is capable of showing defects present in the object. Currently, there are many algorithms such as the Total Focusing Method (TFM), B-scans, and the Synthetic Aperture Focusing Technique (SAFT) which are used. Each of these algorithms have advantages and disadvantages including clarity, data requirements, and speed of implementation. This paper will go over a handful of popular post processing algorithms and compare them over various metrics in order to evaluate them.