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Geometry of a circular disc source.
Source publication
Medical ultrasound data suffers from blur caused by the volume expansion of the pressure field of the mechanical wave. This blur is dependent on the used excitation signal and focusing of the ultrasonic wave and can therefore be examined and manipulated to compute a set of better parameters for deconvolution on the data in order to improve overall...
Contexts in source publication
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... a circular disc (Fig. 1) the spatial impulse response supports an analytical solution [3] which can be obtained for both two situations: when the observation point is inside the aperture of the disc and when is outside the aperture. The disc is assumed to be located in the xy plane centered at 0 y x and the distance in the xy plane from the center axis of ...
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... two different value of sound speed (for tissue is 1450 m/s respectively 330 m/s in air) and for three different distance z: z 1 =5 mm, z 2 =10 mm, z 3 =20 mm it was calculated the pressure response from a single transducer. In this study were considered three types of transducer geometry: circular disc with r=10 mm (Fig. 1), spherical concave with r =10 mm R=100 mm (Fig. 2) and cylindrical concave with a=10 mm, b=20 mm and R=100 mm (Fig. 3). z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a circular disc (1450m/s) Fig. 5. The pressure response at z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a circular disc (330m/s). z 1 =5mm(a), z 2 =10 mm(b), z 3 ...
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... this study were considered three types of transducer geometry: circular disc with r=10 mm (Fig. 1), spherical concave with r =10 mm R=100 mm (Fig. 2) and cylindrical concave with a=10 mm, b=20 mm and R=100 mm (Fig. 3). z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a circular disc (1450m/s) Fig. 5. The pressure response at z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a circular disc (330m/s). ...
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... the pressure response from a single transducer. In this study were considered three types of transducer geometry: circular disc with r=10 mm (Fig. 1), spherical concave with r =10 mm R=100 mm (Fig. 2) and cylindrical concave with a=10 mm, b=20 mm and R=100 mm (Fig. 3). z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a circular disc (1450m/s) Fig. 5. The pressure response at z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a circular disc (330m/s). z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a spherical concave source (1450m/s). For more complex geometry such is cylindrical concave source, the pressure response spectra presented in Figs. 8 and 9 is different. Figs. 8 and 9 shows the frequency response calculated at various distances from the front of the transducer. It is ...
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... pressure response at z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a circular disc (330m/s). z 1 =5mm(a), z 2 =10 mm(b), z 3 =20mm(c) from a spherical concave source (1450m/s). For more complex geometry such is cylindrical concave source, the pressure response spectra presented in Figs. 8 and 9 is different. ...
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Citations
The fast nearfield method, when combined with time-space decomposition, is a rapid and accurate approach for calculating transient nearfield pressures generated by ultrasound transducers. However, the standard time-space decomposition approach is only applicable to certain analytical representations of the temporal transducer surface velocity that, when applied to the fast nearfield method, are expressed as a finite sum of products of separate temporal and spatial terms. To extend time-space decomposition such that accelerated transient field simulations are enabled in the nearfield for an arbitrary transducer surface velocity, a new transient simulation method, frequency-domain time-space decomposition (FDTSD), is derived. With this method, the temporal transducer surface velocity is transformed into the frequency domain, and then each complex-valued term is processed separately. Further improvements are achieved by spectral clipping, which reduces the number of terms and the computation time. Trade-offs between speed and accuracy are established for FDTSD calculations, and pressure fields obtained with the FDTSD method for a circular transducer are compared with those obtained with Field II and the impulse response method. The FDTSD approach, when combined with the fast nearfield method and spectral clipping, consistently achieves smaller errors in less time and requires less memory than Field II or the impulse response method.
