Using redundancy of round-trip ultrasound signal for non-continuous arrays: Application to gap and blockage compensation

• Published in: The Journal of the Acoustical Society of America Vol. 138; no. 5; p. 3375
• Main Authors: Robert, Jean-Luc, Erkamp, Ramon, Korukonda, Sanghamithra, Vignon, François, Radulescu, Emil
• Format: Journal Article
• Language: English
• Published: United States 01.11.2015
• ISSN: 1520-8524
• DOI: 10.1121/1.4934952

In ultrasound imaging, an array of elements is used to image a medium. If part of the array is blocked by an obstacle, or if the array is made from several sub-arrays separated by a gap, grating lobes appear and the image is degraded. The grating lobes are caused by missing spatial frequencies, corresponding to the blocked or non-existing elements. However, in an active imaging system, where elements are used both for transmitting and receiving, the round trip signal is redundant: different pairs of transmit and receive elements carry similar information. It is shown here that, if the gaps are smaller than the active sub-apertures, this redundancy can be used to compensate for the missing signals and recover full resolution. Three algorithms are proposed: one is based on a synthetic aperture method, a second one uses dual-apodization beamforming, and the third one is a radio frequency (RF) data based deconvolution. The algorithms are evaluated on simulated and experimental data sets. An application could be imaging through ribs with a large aperture.