Improvement of 3D ultrasound computer tomography images by signal pre-processing

Ultrasound computer tomography using synthetic aperture focusing technique is sensitive to phase aberration errors. We propose a signal preprocessing method for coherent imaging, which can take the system specific phase aberration into account. The method detects local maxima in the envelope of a matched filtered signal and convolutes the result with a truncated difference of sinc-functions, where the main lobe is scaled to represent the phase aberration. For our system we could show that reflectivity images reconstructed such pre-processed signals are approximately within a factor two of the ideal resolution, while increasing the contrast by a factor of 30.