P3D-2 Phase Aberration Correction for 3D Ultrasound Computer Tomography Images

Our experimental setup for ultrasound computer tomography (USCT) has a cylindrical aperture with a diameter of 18 cm and height of 15 cm. In this setup ultrasound can travel over long distances up to 50 cm. Phase aberration due to speed of sound variations cause many pulses not to overlap in the reflectivity reconstruction. 3D speed of sound (SOS) maps were calculated using the recorded data and applied for correction. Due to a sparse sampling of the received transmission signals, the resulting speed of sound maps are noisy and of low detail. But the accuracy of the average speed of sound is sufficient for phase aberration correction of the reflection images down to object size of approx. 1 mm and increases the image quality significantly. Our work shows that high resolution USCT is not possible without phase aberration correction using SOS information.