Spatio-temporal coding in complex media for optimum beamforming : the iterative time-reversal approach
Spatio-temporal encoding in transmit and receive modes is of major importance in the development of ultrasound imaging devices. Classically, the assumption of constant sound speed in the medium allows one to restrict the beamforming process to the application of a cylindrical time-delay law on the e...
| Veröffentlicht in: | IEEE transactions on ultrasonics, ferroelectrics, and frequency control. - 1999. - 52(2005), 2 vom: 21. Feb., Seite 220-30 |
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| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2005
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| Zugriff auf das übergeordnete Werk: | IEEE transactions on ultrasonics, ferroelectrics, and frequency control |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't |
| Zusammenfassung: | Spatio-temporal encoding in transmit and receive modes is of major importance in the development of ultrasound imaging devices. Classically, the assumption of constant sound speed in the medium allows one to restrict the beamforming process to the application of a cylindrical time-delay law on the elements of a multiple-transducer array. Here is proposed an iterative time-reversal method capable of taking into account all the heterogeneities of the medium, concerning density, speed of sound, and absorption variations. It will be shown that this iterative focusing process converges toward a spatio-temporal inverse filter focusing, the first step of the process being a time-reversal focusing on the targeted point. This method can be seen as a calibration process and has been successfully applied to transskull focusing and intraplate echoes suppression. It is leading the way to promising applications such as high-resolution ultrasonic brain imaging and high-resolution focusing through complex reverberating media, in nondestructive testing and telecommunications. This work highlights the advantages of using spatio-temporal coding to focus through complex media. Such codes require the use of fully programmable, multichannel electronics to implement this technique in real time |
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| Beschreibung: | Date Completed 03.05.2005 Date Revised 17.09.2019 published: Print Citation Status MEDLINE |
| ISSN: | 0885-3010 |