Ultrasonic Synthetic Aperture Focusing Using the Root-Mean-Square Velocity

Synthetic aperture focusing techniques for ultrasonic imaging of solid objects

Synthetic aperture focusing technique (SAFT) has been used in non-destructive testing mainly in its simplest form that mimics acoustic lenses used for focusing ultrasonic beams at a point of a solid object or structure. This paper presents a review of SAFT algorithms applied for post-processing of ultrasonic data acquired in non-destructive inspection of metals. The performance of SAFT in terms...

Velocity estimation using synthetic aperture imaging

In a previous paper we have demonstrated that the velocity can be estimated for a plug flow using recursive ultrasound imaging [1]. The approach involved the estimation of the velocity at every emission and using the estimates for motion compensation. An error in the estimates, however, would lead to an error in the compensation further increasing the error in the estimates. In this paper the a...

Ultrasonic evaluation of friction stir welds and dissimilar intermixing using synthetic aperture focusing technique

Friction stir welding (FSW) is a recently developed solid-state joining process that uses a specially shaped rotating tool to produce lap or butt joints. At the National Research Council, an inter-institute collaboration was started in 2007 with the goal of exploiting the NDE expertise and applying it for the characterization of friction stir welds for various industrial applications. In partic...

Evaluation of Friction Stir Spot Welding Process by Laser Ultrasonic Method with Synthetic Aperture Focusing Technique

The application of laser ultrasonic technique is developed for evaluation of friction stir spot welding (FSSW) quality. The features of laser-generated ultrasonic waves in good welding and incomplete fusion area are simulated by finite element method (FEM). The non-contact laser ultrasonic inspection system (LUIS) was established to verify the numerical results. The interaction of laser ultraso...

Synthetic Aperture Methods for Medical Ultrasonic Imaging