Document Type : Full Research Paper
Authors
1 PhD Candidate, Department of Biomedical Engineering, School of Electrical and Computer Engineering, Tarbiat Modares University
2 Associate Professor, Department of Biomedical Engineering, School of Electrical and Computer Engineering, Tarbiat Modares University
Abstract
In recent years, adaptive beam forming methods have been successfully applied to medical ultrasound imaging, resulting in significant improvement in image quality compared to non-adaptive beam formers. This improvement results from the fact that their weights are chosen based on the priori knowledge of the received data and updated using current statistics of the array signal. Most of the adaptive beam formers presented in the ultrasound imaging literature are based on the minimum variance (MV) beam former, which can improve the imaging resolution while retaining the contrast. It is desirable that the beam former could improve the resolution and contrast, at the same time. To this end, in this paper, we have used temporal averaging besides the conventional spatial averaging to estimate the more accurate covariance matrix. Moreover, we have used the coherence factor weighting combined with MV beam forming to enhance the focusing quality and hence reducing the undesired side lobes. The efficacy of the proposed adaptive beam forming approach is demonstrated via a number of simulated and experimental examples.
Keywords
- ultrasound imaging
- Resolution
- contrast
- Adaptive Beam Forming
- Minimum Variance Beam Forming
- Coherence Factor Weighting
- Temporal Averaging
- Covariance Matrix Estimation
Main Subjects