k-Wave User Forum » Topic: Elastic wave simulation for two medium

k-Wave User Forum » Topic: Elastic wave simulation for two medium http://www.k-wave.org/forum/topic/elastic-wave-simulation-for-two-medium Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:34:29 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php masud407 on "Elastic wave simulation for two medium" http://www.k-wave.org/forum/topic/elastic-wave-simulation-for-two-medium#post-8782 Tue, 30 May 2023 21:00:49 +0000 masud407 8782@http://www.k-wave.org/forum/ Dr. Treeby, thanks for your reply. By the image example, what did you mean as I haven't foind any attachment here? Also, you meant that I don't need to simulate ARF using K-wave, but I can get the similar outcomes, is this what you meant? Bradley Treeby on "Elastic wave simulation for two medium" http://www.k-wave.org/forum/topic/elastic-wave-simulation-for-two-medium#post-8781 Tue, 30 May 2023 20:31:36 +0000 Bradley Treeby 8781@http://www.k-wave.org/forum/ You can include a heterogeneous medium in this type of simulation if that’s what you’re asking (see the image examples). Note, k-Wave doesn’t model the actual ARF directly (it’s a second-order effect) but you can output the parameters you need to compute it. masud407 on "Elastic wave simulation for two medium" http://www.k-wave.org/forum/topic/elastic-wave-simulation-for-two-medium#post-8779 Tue, 30 May 2023 18:48:46 +0000 masud407 8779@http://www.k-wave.org/forum/ Thanks, Dr. Treeby. I just changed the medium information. I am confused whether the simulation is okay for heterogenous setup or not. Also, if I want to use the same transducer for ARF generation and tracking (sensor mask), is it possible to do so? Bradley Treeby on "Elastic wave simulation for two medium" http://www.k-wave.org/forum/topic/elastic-wave-simulation-for-two-medium#post-8776 Sun, 28 May 2023 07:35:40 +0000 Bradley Treeby 8776@http://www.k-wave.org/forum/ What have you changed from the example and what are you stuck on? masud407 on "Elastic wave simulation for two medium" http://www.k-wave.org/forum/topic/elastic-wave-simulation-for-two-medium#post-8774 Sat, 27 May 2023 22:59:39 +0000 masud407 8774@http://www.k-wave.org/forum/ Hello, I am a new K-wave user. I want to simulate a linear transducer array that will generate ARF at the interface of the two medium. I used the example code for defining the diagnostic transducer. I am not sure if the following code is correct or not. Anyone please help? close all; clear all; clearvars; % simulation settings DATA_CAST = 'single'; % ========================================================================= % DEFINE THE K-WAVE GRID % ========================================================================= % set the size of the perfectly matched layer (PML) PML_X_SIZE = 20; % [grid points] PML_Y_SIZE = 10; % [grid points] PML_Z_SIZE = 10; % [grid points] % set total number of grid points not including the PML Nx = 128 - 2*PML_X_SIZE; % [grid points] Ny = 128 - 2*PML_Y_SIZE; % [grid points] Nz = 64 - 2*PML_Z_SIZE; % [grid points] % set desired grid size in the x-direction not including the PML x = 40e-3; % [m] % calculate the spacing between the grid points dx = x/Nx; % [m] dy = dx; % [m] dz = dx; % [m] % create the k-space grid kgrid = kWaveGrid(Nx, dx, Ny, dy, Nz, dz); % ========================================================================= % DEFINE THE MEDIUM PARAMETERS % ========================================================================= %define the properties of the propagation medium medium.sound_speed = 2000.*ones(Nx,Ny,Nz) ; % [m/s] 2nd medium.sound_speed(1:Nx/2,:,:) = 1000 ; % [m/s] 1st 101 medium.density = 2000*ones(Nx,Ny,Nz); % [kg/m^3] 2nd medium.density(1:round(Nx/2),:,:) = 1134 ; % [kg/m^3] 1st medium.alpha_coeff = 0.001*ones(Nx,Ny,Nz); % [dB/(MHz^y cm)] 2nd medium.alpha_coeff(1:round(Nx/2),:,:)=0.01 ; % [dB/(MHz^y cm)] 1st medium.alpha_power = 1.5; medium.BonA = 6; % create the time array t_end = 40e-6; % [s] kgrid.makeTime(medium.sound_speed, [], t_end); % ========================================================================= % DEFINE THE INPUT SIGNAL % ========================================================================= % define properties of the input signal source_strength = 1e6; % [Pa] tone_burst_freq = 0.5e6; % [Hz] tone_burst_cycles = 5; % create the input signal using toneBurst input_signal = toneBurst(1/kgrid.dt, tone_burst_freq, tone_burst_cycles); % scale the source magnitude by the source_strength divided by the % impedance (the source is assigned to the particle velocity) input_signal = (source_strength ./ (1000 .* 1134)) .* input_signal; % ========================================================================= % DEFINE THE ULTRASOUND TRANSDUCER % ========================================================================= % physical properties of the transducer transducer.number_elements = 72; % total number of transducer elements transducer.element_width = 1; % width of each element [grid points] transducer.element_length = 12; % length of each element [grid points] transducer.element_spacing = 0; % spacing (kerf width) between the elements [grid points] transducer.radius = inf; % radius of curvature of the transducer [m] % calculate the width of the transducer in grid points transducer_width = transducer.number_elements * transducer.element_width ... + (transducer.number_elements - 1) * transducer.element_spacing; % use this to position the transducer in the middle of the computational grid transducer.position = round([1, Ny/2 - transducer_width/2, Nz/2 - transducer.element_length/2]); % properties used to derive the beamforming delays transducer.sound_speed = 1540; % sound speed [m/s] transducer.focus_distance = 10e-3; % focus distance [m] transducer.elevation_focus_distance = 19e-3; % focus distance in the elevation plane [m] transducer.steering_angle = 0; % steering angle [degrees] % apodization transducer.transmit_apodization = 'Rectangular'; transducer.receive_apodization = 'Rectangular'; % define the transducer elements that are currently active transducer.active_elements = zeros(transducer.number_elements, 1); transducer.active_elements(21:52) = 1; % append input signal used to drive the transducer transducer.input_signal = input_signal; % create the transducer using the defined settings transducer = kWaveTransducer(kgrid, transducer); % print out transducer properties transducer.properties; % ========================================================================= % DEFINE SENSOR MASK % ========================================================================= % create a binary sensor mask with four detection positions sensor.mask = zeros(Nx, Ny, Nz); sensor.mask([Nx/4, Nx/2, 3*Nx/4], Ny/2, Nz/2) = 1; % ========================================================================= % RUN THE SIMULATION % ========================================================================= % set the input settings input_args = {'DisplayMask', transducer.all_elements_mask | sensor.mask, ... 'PMLInside', false, 'PlotPML', false, 'PMLSize', [PML_X_SIZE, PML_Y_SIZE, PML_Z_SIZE], ... 'DataCast', DATA_CAST, 'PlotScale', [-1/2, 1/2] * source_strength}; % run the simulation [sensor_data] = kspaceFirstOrder3D(kgrid, medium, transducer, sensor, input_args{:}); % calculate the amplitude spectrum of the input signal and the signal % recorded each of the sensor positions [f_input, as_input] = spect([input_signal, zeros(1, 2 * length(input_signal))], 1/kgrid.dt); [~, as_1] = spect(sensor_data(1, :), 1/kgrid.dt); [~, as_2] = spect(sensor_data(2, :), 1/kgrid.dt); [f, as_3] = spect(sensor_data(3, :), 1/kgrid.dt); % ========================================================================= % VISUALISATION % ========================================================================= % plot the input signal and its frequency spectrum figure; subplot(2, 1, 1); plot((0:kgrid.dt:(length(input_signal) - 1) * kgrid.dt) * 1e6, input_signal, 'k-'); xlabel('Time [\mus]'); ylabel('Particle Velocity [m/s]');