A Circular Total Focusing Method With Eccentricity Correction and Intensity Compensation for Endoscopic Ultrasound Imaging of Dual-Layered Media.

Present endoscopic ultrasound (EUS) imaging methods for circular array (CA) suffer from the nonuniform spatial resolution in the imaging of a dual-layered media, such as the tubes' immersion EUS inspection. The problem is mainly attributed to the restricted focus and beam de-focusing at the interface. In this article, a circular total focusing method (CTFM) is proposed, which leverages the concept of the conventional total focusing method (TFM) and makes three vital improvements to overcome the challenges.

A General Approach for Optimization of Ultrasonic Array Parameter and Setup Using Principal Component Regression.

When an optimization approach is taken for ultrasonic array design, the relationship between imaging performance and acoustic beam characteristics (ABCs) needs to be considered. A general optimization approach for ultrasonic array design is proposed based on principal component regression (PCR), which is used to establish the relationship between imaging performance indicators (IPIs) and ABC. A linear and a circular ultrasonic array design scenarios are simulated to demonstrate the effectiveness of the proposed approach.

Simulation and performance study of circular ultrasonic array for tubes' internal inspection.

A circular array (CA) transducer is developed and validated to implement internal inspection of the small diameter tubes, one of whose potential application targets is the heat exchanger tubes in Modular High Temperature Gas-cooled Reactor. A geometric model of the transducer and the delay law are proposed according to the inspection setup. Using k-Wave, an open source acoustic simulation toolbox, the beam profiles of various aperture sizes are analyzed to select a suitable aperture.

Development and Validation of Independent Dual-Focusing Transducer for Internal Inspection of Tubes.

Controllable and focused ultrasonic beams in 3-D cylindrical space are essential when inspecting tubes or tubular objects. In this article, we develop an independent dual-focusing (IDF) array ultrasonic transducer composed of 64 prefocused elements and validate the feasibility of this design. Using k-Wave toolbox based on the k-space pseudospectral method, we simulate the acoustic pressure fields in the time domain and analyze beam profiles in circumferential-radial plane, axial-radial plane and 3-D space.