A New Direct Pixel Based Focusing Method for Medical Ultrasound Imaging: Preliminary Results

초록

In medical ultrasound imaging, scan conversion is used to geometrically transform polar coordinate ultrasound data into Cartesian raster data for display. In scan conversion, Moire undersampling artifacts can be avoided by using various interpolation techniques such as nearest neighbor and bilinear. However, this interpolation-based scan conversion introduces blurring of fine details in ultrasound images. In this paper, a new beamforming technique, named compounded direct pixel beamforming (CDPB), is proposed to remove blurring artifacts from scan conversion. In CDPB, receive focusing is performed directly on each display pixel in Cartesian coordinates with raw radio-frequency (RF) data from two adjacent transmit firings so that artifacts from scan conversion can be substantially removed. To evaluate the proposed CDPB method, 64-channel pre-beamformed RF data were captured by a commercial ultrasound machine (SA-9900, Medison Corp., Seoul, Korea) from a tissue mimicking phantom (ATS Laboratories, Bridgeport, CT, USA). To quantify the performance of the proposed method, the information entropy contrast (IEC) value was measured. From the experiments, the proposed method provided IEC improvement by 2.8 over the conventional scan conversion method. These results indicate that the proposed new beamforming method could be used for enhancing the image quality in medical ultrasound imaging.

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