3D Synthetic Aperture Technique for Ultrasonic Imaging

Abstract: The group for non-destructive testing at Uppsala University has recently implemented the phase shift migration method, which is a method to focus images acquired unfocused using ultrasound. However, their work has been limited to 2D data, while for many applications the gathered data is 3D. This project has extended the old implementation to 3D data. The new implementation has been done in two different ways, giving one algorithm that works fast but needs much RAM, and one algorithm that takes long time but works on smaller computers, not demanding as much memory. The fast algorithm works faster than the time it takes to acquire the raw data, which makes real-time use realistic. To test the performance of the two algorithms with respect to image improvement, both against each other and against the previous 2D implementation, a number of experiments were carried out, which showed that, apart from processing time, the two new algorithms were equal in performance. The experiments also showed that the obtained resolution in both x- and y-directions matched the theoretical discussion.