Multi-Stage Adaptive Noise Cancellation for Ultrasonic Nondestructive Evaluation
A major source of noise or clutter in ultrasonic nondestructive evaluation (NDE) applications is due to the grain structure of the material. The scattering of ultrasonic waves from grain boundaries can interfere and introduce artifacts in the received signal that can sometimes mask indications due to a small flaw. For instance, the grain noise can hinder the detection of small but potentially dangerous flaws, such as hard-α inclusion in titanium alloy components . In general, the grains are randomly distributed within a material. The grain noise is therefore spatially varying and can be modeled as a stochastic process .