[4A6] Use of orthogonal signals to increase the rate of data acquisition in plane wave imaging
K Prashar¹,², M Weston² and B Drinkwater¹
¹University of Bristol, UK
²TWI, UK
Phased array ultrasound testing (PAUT) is now a widely used method in industry for non-destructive testing. Arrays offer an intuitive view of the interior of a component from which geometric features and defects can be observed. Arrays also offer unprecedented information about the nature and extent of any defects. In recent years, full matrix capture (FMC) and the total focusing method (TFM) have attracted significant interest due to the high resolution of the images possible throughout an inspection volume. In certain industrial scenarios where very fast scan speeds are desired, algorithms such as plane-wave imaging (PWI) have been introduced to increase data acquisition speeds while retaining similar imaging quality of FMC/TFM-based algorithms. The motivation of this paper is to find methods to further increase the speed of data acquisition in the PWI algorithm, while maintaining acceptable image quality. To accomplish this, the use of coded-excitation signals in the form of frequency modulated signals are used to create orthogonal signals that have the potential to be fired simultaneously, therefore increasing the speed of data acquisition in PWI. The performance of this new technique is then compared in simulation and through experimentation with different signal and sample parameters and compared with normal PWI.
