| Autor: |
Sjo\j, Sidsel M. N., Blanco, Esther N., Wilhjelm, Jens E., Jensen, Henrik, Hemmsen, Martin C., Jensen, Jo\rgen A. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 5/24/2012, Vol. 1433 Issue 1, p211-214, 4p, 1 Color Photograph, 1 Black and White Photograph, 1 Chart, 1 Graph |
| Abstrakt: |
The echo from planar surfaces with rms roughness, Rq, in the range from 0-155 μm was measured with a clinical linear array transducer at different angles of incidence at 6 MHz and 12 MHz. The echo-pulse from the surfaces was isolated with an equal sized window and the power of the echo-pulse was calculated. The power of the echo from the smooth surface (Rq = 0) is highly angle-dependent due to a high degree of specular reflection. Within the angular range considered here, -10° to 10°, the variation spans a range of 18 dB at both 6 MHz and 12 MHz. When roughness increases, the angle-dependence decreases, as the echo process gradually changes from pure reflection to being predominantly governed by backscattering. The power of the echoes from the two roughest surfaces (Rq = 115 μm and 155 μm) are largely independent of angle at both 6 MHz and 12 MHz with a variation of 2 dB in the angular range from -10° to 10°. The least rough surfaces (Rq = 32 μm and 89 μm) have responses in between with a higher degree of angle-dependence at 6 MHz than at 12 MHz. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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