### Abstract

Original language | English |
---|---|

Title of host publication | 2005 IEEE Ultrasonics symposium |

Volume | 1-4 |

Publisher | IEEE |

Publication date | 2005 |

Pages | 141-145 |

ISBN (Print) | 0-7803-9382-1 |

DOIs | |

Publication status | Published - 2005 |

Event | 2005 IEEE Ultrasonics Symposium - Rotterdam, Netherlands Duration: 18 Sep 2005 → 21 Sep 2005 http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=10674 |

### Conference

Conference | 2005 IEEE Ultrasonics Symposium |
---|---|

Country | Netherlands |

City | Rotterdam |

Period | 18/09/2005 → 21/09/2005 |

Internet address |

Series | I E E E International Ultrasonics Symposium. Proceedings |
---|---|

ISSN | 1051-0117 |

### Keywords

- Medical
- Velocity estimation
- Ultrasound

### Cite this

*2005 IEEE Ultrasonics symposium*(Vol. 1-4, pp. 141-145). IEEE. I E E E International Ultrasonics Symposium. Proceedings https://doi.org/10.1109/ULTSYM.2005.1602816

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*2005 IEEE Ultrasonics symposium.*vol. 1-4, IEEE, I E E E International Ultrasonics Symposium. Proceedings, pp. 141-145, 2005 IEEE Ultrasonics Symposium, Rotterdam, Netherlands, 18/09/2005. https://doi.org/10.1109/ULTSYM.2005.1602816

**Spectral Velocity Estimation using the Autocorrelation Function and Sparse data Sequences.** / Jensen, Jørgen Arendt.

Research output: Chapter in Book/Report/Conference proceeding › Article in proceedings › Research › peer-review

TY - GEN

T1 - Spectral Velocity Estimation using the Autocorrelation Function and Sparse data Sequences

AU - Jensen, Jørgen Arendt

PY - 2005

Y1 - 2005

N2 - Ultrasound scanners can be used for displaying the distribution of velocities in blood vessels by finding the power spectrum of the received signal. It is desired to show a B-mode image for orientation and data for this has to be acquired interleaved with the flow data. Techniques for maintaining both the B-mode frame rate, and at the same time have the highest possible $f_{prf}$ only limited by the depth of investigation, are, thus, of great interest. The power spectrum can be calculated from the Fourier transform of the autocorrelation function $R_r(k)$. The lag $k$ corresponds to the difference in pulse number, so that for lag $k$ data from emission $i$ is correlated with $i+k$. It is possible to calculate $R_r(k)$ for a sparse set of emissions, as long as all combinations of emissions cover all lags in $R_r(k)$. A sparse set of emissions interleaved with B-mode emissions can, therefore, be used for estimating $R_r(k)$. The approach has been investigated using Field II simulation of the flow in the carotid and femoral arteries. A 5 MHz linear array transducer with 128 elements, a pitch of $\lambda$ and an element height of 5 mm was simulated. The autocorrelation was calculated from the sparse sequence and averaged over a pulse length. The 1:2 sequence using 2 flow emission for one b-Mode emissions showed a nearly indistinguishable spectrum compared to a Fourier spectrum calculated on the full data. The sparser sequences give a higher noise in the spectrum proportional to the sparseness of the sequence. The audio signal has also been synthesized from the autocorrelation data by passing white, Gaussian noise through a filter designed from the power spectrum of the autocorrelation function. The results show that both the full velocity range can be maintained at the same time as a B-mode image is shown in real time, where the trade-off between B-mode frame rate and spectral accuracy can be selected.

AB - Ultrasound scanners can be used for displaying the distribution of velocities in blood vessels by finding the power spectrum of the received signal. It is desired to show a B-mode image for orientation and data for this has to be acquired interleaved with the flow data. Techniques for maintaining both the B-mode frame rate, and at the same time have the highest possible $f_{prf}$ only limited by the depth of investigation, are, thus, of great interest. The power spectrum can be calculated from the Fourier transform of the autocorrelation function $R_r(k)$. The lag $k$ corresponds to the difference in pulse number, so that for lag $k$ data from emission $i$ is correlated with $i+k$. It is possible to calculate $R_r(k)$ for a sparse set of emissions, as long as all combinations of emissions cover all lags in $R_r(k)$. A sparse set of emissions interleaved with B-mode emissions can, therefore, be used for estimating $R_r(k)$. The approach has been investigated using Field II simulation of the flow in the carotid and femoral arteries. A 5 MHz linear array transducer with 128 elements, a pitch of $\lambda$ and an element height of 5 mm was simulated. The autocorrelation was calculated from the sparse sequence and averaged over a pulse length. The 1:2 sequence using 2 flow emission for one b-Mode emissions showed a nearly indistinguishable spectrum compared to a Fourier spectrum calculated on the full data. The sparser sequences give a higher noise in the spectrum proportional to the sparseness of the sequence. The audio signal has also been synthesized from the autocorrelation data by passing white, Gaussian noise through a filter designed from the power spectrum of the autocorrelation function. The results show that both the full velocity range can be maintained at the same time as a B-mode image is shown in real time, where the trade-off between B-mode frame rate and spectral accuracy can be selected.

KW - Medical

KW - Velocity estimation

KW - Ultrasound

U2 - 10.1109/ULTSYM.2005.1602816

DO - 10.1109/ULTSYM.2005.1602816

M3 - Article in proceedings

SN - 0-7803-9382-1

VL - 1-4

SP - 141

EP - 145

BT - 2005 IEEE Ultrasonics symposium

PB - IEEE

ER -