IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control · 2006 · 101 citations · 23 references
EngineeringBiomedical EngineeringElectrical EngineeringBiomedical ImagingUltrasonographyUltrasoundBeamformingDiagnostic UltrasonographyTransducer TechnologyUltrasonicsUltrasound ImagingUltrasound InstrumentationHigh-frequency Ultrasound SystemsLinear Array TransducersTransducersUltrasonic ImagingUltrasonic Transducer ArraysUltrasound BeamformingUltrasound Image AcquisitionUltrasound Imaging Transducers
A real-time digital beamformer for high-frequency (>20 MHz) linear ultrasonic arrays has been developed. The system can handle up to 64-element linear array transducers and excite 16 channels and receive simultaneously at 100 MHz sampling frequency with 8-bit precision. Radio frequency (RF) signals are digitized, delayed, and summed through a real-time digital beamformer, which is implemented using a field programmable gate array (FPGA). Using fractional delay filters, fine delays as small as 2 ns can be implemented. A frame rate of 30 frames per second is achieved. Wire phantom (20 microm tungsten) images were obtained and -6 dB axial and lateral widths were measured. The results showed that, using a 30 MHz, 48-element array with a pitch of 100 microm produced a -6 dB width of 68 microm in the axial and 370 microm in the lateral direction at 6.4 mm range. Images from an excised rabbit eye sample also were acquired, and fine anatomical structures, such as the cornea and lens, were resolved.
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Splitting the unit delay [FIR/all pass filters design]
T.I. Laakso, Vesa Välimäki, Matti Karjalainen et al. · IEEE Signal Processing Magazine · 1996 · 1.1K citations
A new ultrasound instrument for in vivo microimaging of mice
F. Stuart Foster, M.Y. Zhang, Yuqing Zhou et al. · Ultrasound in Medicine & Biology · 2002 · 341 citations