Bioautomation (Dec 2006)
Adaptive Phase Aberration Correction in Multi-Element Synthetic Aperture Imaging Systems
Abstract
The problem of phase aberration correction in Multi-element Synthetic Aperture Focusing (MSAF) imaging systems is considered in this paper. In the MSAF imaging, the phase distortions caused by tissue inhomogenities can be adaptively estimated and compensated in two successive stages of signal processing - partial beamforming (low-resolution image) and synthetic aperture formation (high-resolution image). In this paper, two methods that can be used for phase correction at the stage of high-resolution image formation are studied - a Full Common Spatial Frequency (FCSF) technique and a Partial Common Spatial Frequency (PCSF) technique. The two techniques are based on the estimate of the cross-correlation function between low-resolution images, which is used for evaluation of phase aberration errors when forming a final high-resolution image. The effectiveness of each technique for phase aberration correction is determined by the improvement factor, which is defined as difference in dynamic range between the corrected image and the distorted one.
