Non-cylindrical transmission focusing for large depth of field

Shin Ichiro Umemura, Takashi Azuma, Yuichi Miwa, Kazuaki Sasaki, Takashi Sugiyama, Tatsuhiko Hayashi, Hiroshi Kuribara

Research output: Contribution to journalConference articlepeer-review

4 Citations (Scopus)


In imaging with a micro-bubble contrast agent, which tends to make irreversible changes by transmission even at a low intensity, both transmission beamwidth and number of transmission per frame must be minimized. A transmission focusing technique based on a non-cylindrical delay, which is applicable to a one-dimensional array, is proposed. Unlike X waves, the main beam propagates always coherently with the waves transmitted from the central part of the aperture. The non-cylindrical focusing delay was calculated by assuming a local focal length along the aperture, which increases gradually as the distance from the center increases. Numerical simulation of wave propagation predicted a large depth of field for a reasonably narrow main beam having longitudinally uniform intensity. The non-cylindrical focusing was employed in a prototype beamformer, and the large depth of transmission field was confirmed with Shrielen measurements.

Original languageEnglish
Pages (from-to)1721-1724
Number of pages4
JournalProceedings of the IEEE Ultrasonics Symposium
Publication statusPublished - 2002 Dec 1
Event2002 IEEE Ultrasonics Symposium - Munich, Germany
Duration: 2002 Oct 82002 Oct 11

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


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