Segmented motion compensation for complementary coded ultrasonic imaging

Abstract

Ultrasonic imaging using complementary coded pulses offers the SNR improvements of signal coding without the filter side-lobes introduced by single-transmit codes. Tissue motion between coded pulse emissions, however, can introduce high side-lobes caused by misalignment of complementary filter outputs. This paper presents a method for filtering and motion compensation of complementary coded signals appropriate for use in medical imaging. The method is robust to the effects of non-ideal transducers on the imaging signals, includes mirrored compensation stages to reduce the impact of motion estimation error, and has been shown to reduce side-lobes to levels that compare favorably to systems using FM-coded signals of similar length and bandwidth while providing increased coding gain and range resolution. In addition, motion compensation allows the received data to be used without the frame-rate penalty usually incurred by complementary-coded imaging. The method has been verified using simulated point and speckle targets with both homogeneous and inhomogeneous motion profiles. Selected results have been verified experimentally.

Nonlinear Harmonic Distortion of Complementary Golay Codes

“…4 Despite this, some have found their use in blood flow imaging 6,7 and others have devised motion compensation techniques to ensure good summation. 3 Every aspect of pulse compression using binary phase coded excitations must therefore be optimized to gain the most performance for low-power, low-cost ultrasound systems.…”

“…Pulse compression has been used in a wide range of technologies from it’s conception in radar imaging through to telecommunications and ultrasonic imaging, which first saw successful implementation in diagnostic ultrasound machines in the 1990s 3 and grew in popularity as ultrasound scanners reached the Mechanical Index (MI) limit imposed by regulatory bodies.…”

“… 4 Despite this, some have found their use in blood flow imaging 6 , 7 and others have devised motion compensation techniques to ensure good summation. 3 …”

New Construction of Quadriphase Golay Complementary Pairs

“…A Golay complementary pair (GCP) consists of two equal-length sequences whose aperiodic autocorrelation functions (AACFs) sum to zero for all non-zero time shifts [1]. Exactly due to impulse-like AACF sums of GCPs, GCPs can be applied to optical spectroscopy [2], pulsed radar for range detection [3], radar clutter rejection [4], improvement of signal detection range [5] or resolution [6] in radar systems, digital watermarking [7], and ultrasonic imaging [8]. In particular, GCPs play fairly important roles in MIMO CDMA wireless communications, which is in detail surveyed by [9].…”

Slow-time Golay decoding for Doppler detection of high-velocity blood flow

“…Though the complementary Golay code has the advantages of low range side lobe and low implementation cost, it requires multiple transmissions for each scan line and thus could suffer from severe motion artifact [6]. Therefore, the Golay code is conventionally regarded as not applicable to blood flow detection, especially with high flow velocity.…”