Users’ guide for the Field II program
Release 3.20, November 19, 2010
Jørgen Arendt Jensen
May 6, 2011
Jørgen Arendt Jensen
May 6, 2011
Department of Electrical Engineering, Build. 349,
Technical University of Denmark
DK-2800 Lyngby, Denmark
E-mail: jaj@elektro.dtu.dk
Web: http://server.elektro.dtu.dk/www/jaj/field/
CONTENTS
1 Introduction 3
2 Program organization 5
3 Method of simulation 7
3.1 The spatial impulse response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2 Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3 Focusing and apodization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.4 Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 Installation 9
5 Description of Matlab procedures 11
5.1 List of current procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2 Procedures for Field initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3 Procedures for transducer definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.4 Procedures for element manipulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.5 Procedures for field calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6 Examples 59
6.1 Phased array imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
6.2 Linear array imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
6.3 Flow data generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Bibliography 66
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LIST OF FIGURES
5.1 Concave, round transducer with a radius of 8 mm divided into 1 by 1 mm mathematical elements. . . 19
5.2 Rectangles for a convex array with Rconvex equal to 20 mm. . . . . . . . . . . . . . . . . . . . . . . 21
5.3 Rectangles for an elevation focused, convex array with Rfocus equal to 10 mm and Rconvex equal to
30 mm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.4 Rectangles for an elevation focused, multi-row, convex array with Rfocus equal to 7 mm and Rconvex
equal to 30 mm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.5 Rectangles for an elevation focused, linear array with Rfocus equal to 15 mm. . . . . . . . . . . . . . 26
5.6 Rectangles for an elevation focused, multi-row linear array with Rfocus equal to 10 mm and 5 rows. . 27
5.7 Display of the geometry and apodization of a linear array transducer. . . . . . . . . . . . . . . . . . . 30
5.8 Rectangles for a 16 elements linear array transducer. . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.9 Geomtery of multi-row linear array transducer. Currently x and y has been switched. . . . . . . . . . 33
5.10 Rectangles for a 16 by 5 elements multi-row transducer. . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.11 Piston transducer with a radius of 8 mm divided into 1 by 1 mm mathematical elements. . . . . . . . 36
5.12 Fully populated two-dimensional array with 11 by 13 elements. . . . . . . . . . . . . . . . . . . . . . 43
5.13 Partially populated two-dimensional array with 23 elements. . . . . . . . . . . . . . . . . . . . . . . 44
5.14 Linear array transducer with a fixed apodization of the mathematical elements. . . . . . . . . . . . . 46
5.15 Intensity profile for linear array transducer with an elevation focus lens. . . . . . . . . . . . . . . . . 47
5.16 Example of calculated response when using different physical element excitations. . . . . . . . . . . 49
5.17 Received voltage traces from the individual elements of a 16 elements linear array transducer, when
transmitting with three different elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.18 Received voltage traces from the individual elements of a linear array transducer (top) and the sum of
all the individual responses (bottom). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
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