| This paper describes recently held research about combining two methods of autocorrelation based normal Tissue Doppler Imaging (TDI) and Synthetic Aperture Imaging (SAI). Doppler shift estimator based on autocorrelation has been widely used to various commercial TDI system because of its simple structure, robustness, and low computation power requirements. And through application of SAI, spatial resolution, contrast resolution and SNR can be improved without a drop of frame rate so it¡¯s been researched until recent and the system utilizing this method will be shown to the market sooner or later. Since both methods are based on quite different approaches, direct combination of two methods has various problems. To solve these problems, source position staggering method is proposed in this paper. As a result, frame rate can be maintained as a normal B mode with stable TDI. Proposed method is verified by Field II computer simulation and off-line processing of the actual echo signal obtained from the human body. |