k-Wave

k-Wave Toolbox

• Getting Started
• Run the First Example
• Build Your Own Simulation
• Troubleshooting
• Reference List
• Examples
• Initial Value Problems
• Example: Homogenous Propagation Medium
• Example: Using A Binary Sensor Mask
• Example: Defining A Sensor Mask By Opposing Corners
• Example: Loading External Image Maps
• Example: Heterogeneous Propagation Medium
• Example: Saving Movie Files
• Example: Recording The Particle Velocity
• Example: Defining A Gaussian Sensor Frequency Response
• Example: Comparison Of Modelling Functions
• Example: Setting An Initial Pressure Gradient
• Example: Simulations In One Dimension
• Example: Simulations In Three Dimensions
• Example: Photoacoustic Waveforms in 1D, 2D and 3D
• Time Varying Source Problems
• Example: Monopole Point Source In A Homogeneous Propagation Medium
• Example: Dipole Point Source In A Homogeneous Propagation Medium
• Example: Simulating Transducer Field Patterns
• Example: Steering A Linear Array
• Example: Snell's Law And Critical Angle Reflection
• Example: The Doppler Effect
• Example: Diffraction Through A Slit
• Example: Simulations In Three-Dimensions
• Sensor Directivity
• Example: Focussed Detector in 2D
• Example: Focussed Detector in 3D
• Example: Modelling Sensor Directivity in 2D
• Example: Modelling Sensor Directivity in 3D
• Example: Sensor Element Directivity in 2D
• Example: Focussed 2D Array with Directional Elements
• Photoacoustic Image Reconstruction
• Example: 2D FFT Reconstruction For A Line Sensor
• Example: 3D FFT Reconstruction For A Planar Sensor
• Example: 2D Time Reversal For A Line Sensor
• Example: 2D Time Reversal For A Circular Sensor
• Example: 3D Time Reversal For A Planar Sensor
• Example: 3D Time Reversal For A Spherical Sensor
• Example: Image Reconstruction With Directional Sensors
• Example: Image Reconstruction With Bandlimited Sensors
• Example: Iterative Image Improvement Using Time Reversal
• Example: Attenuation Compensation Using Time Reversal
• Example: Attenuation Compensation Using Time Variant Filtering
• Example: Automatic Sound Speed Selection
• Diagnostic Ultrasound Simulation
• Example: Defining An Ultrasound Transducer
• Example: Simulating Ultrasound Beam Patterns
• Example: Using An Ultrasound Transducer As A Sensor
• Example: Simulating B-mode Ultrasound Images
• Example: Simulating B-mode Images Using A Phased Array
• Numerical Analysis
• Example: Controlling The Absorbing Boundary Layer
• Example: Source Smoothing
• Example: Filtering A Delta Function Input Signal
• Example: Modelling Power Law Absorption
• Example: Modelling Nonlinear Wave Propagation
• Example: Optimising k-Wave Performance
• Using The C++ Code
• Example: Running C++ Simulations
• Example: Saving Input Files in Parts
• Elastic Wave Propagation
• Example: Explosive Source In A Layered Medium
• Example: Plane Wave Absorption
• Example: Shear Waves And Critical Angle Reflection
• Example: Simulations In Three Dimensions
• Functions - By Category
• Functions - Alphabetical List
• Release Notes
• License

k-Wave Toolbox

Steering A Linear Array Example

On this page…
Overview Defining the linear array and input signal Running the simulation

Overview

This example demonstrates how to use k-Wave to steer a tone burst from a linear array transducer in 2D. It builds on the Simulating Transducer Field Patterns Example.

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Defining the linear array and input signal

The source mask is defined by creating a binary mask with the desired source points set to 1.

% define source mask for a linear transducer with an odd number of elements   
num_elements = 21;      % [grid points]
x_offset = 25;          % [grid points]
source.p_mask = zeros(Nx, Ny);
start_index = Ny/2 - round(num_elements/2) + 1;
source.p_mask(x_offset, start_index:start_index + num_elements - 1) = 1;

The input signal to each element is then created using the function toneBurst with a geometrically steered temporal offset that varies across the source.

% define the properties of the tone burst used to drive the transducer
sampling_freq = 1/dt;   % [Hz]
steering_angle = 30;    % [deg]
element_spacing = dx;   % [m]
tone_burst_freq = 1e6;  % [Hz]
tone_burst_cycles = 8;

% create an element index relative to the centre element of the transducer
element_index = -(num_elements - 1)/2:(num_elements - 1)/2;

% use geometric beam forming to calculate the tone burst offsets for each
% transducer element based on the element index
tone_burst_offset = 40 + element_spacing*element_index*sin(steering_angle*pi/180)/(medium.sound_speed*dt);

% create the tone burst signals
source.p = toneBurst(sampling_freq, tone_burst_freq, tone_burst_cycles, 'SignalOffset', tone_burst_offset);

A plot of the input signals for each transducer element is shown below.

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Running the simulation

Visualisations of the pressure field at two different times for steering angles of +30 and -20 degrees are shown below.

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Simulating Transducer Field Patterns

Snell's Law And Critical Angle Reflection

© 2009-2014 Bradley Treeby and Ben Cox.