k-Wave User Forum » Topic: Regarding Homogenous B-mode image simulation

k-Wave User Forum » Topic: Regarding Homogenous B-mode image simulation http://www.k-wave.org/forum/topic/regarding-homogenous-b-mode-image-simulation Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 22:54:07 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php Mekdes Bezabh on "Regarding Homogenous B-mode image simulation" http://www.k-wave.org/forum/topic/regarding-homogenous-b-mode-image-simulation#post-9217 Mon, 26 May 2025 21:37:15 +0000 Mekdes Bezabh 9217@http://www.k-wave.org/forum/ Please, I wonder if anyone can suggest any solution. Thank you in advance. Mekdes Bezabh on "Regarding Homogenous B-mode image simulation" http://www.k-wave.org/forum/topic/regarding-homogenous-b-mode-image-simulation#post-9215 Wed, 21 May 2025 18:15:24 +0000 Mekdes Bezabh 9215@http://www.k-wave.org/forum/ Dear All, I have some questions regarding the code "example_us_bmode_linear_transducer." I am trying to create a homogeneous B-mode image without any artifacts. I have tested different values for the tone burst frequency—3.47 MHz, 7.8 MHz, and 15.62 MHz—along with varying values for the medium's alpha coefficient and alpha power, while keeping the sound speed and density uniform. I am using a plane wave setup with the focus set to infinity. However, I encountered some unexpected results: 1. At a frequency of 3.47 MHz, the resulting B-mode image was not as expected. 2. At 7.8 MHz, I observed a bright line in the middle of the final B-mode image. 3. The same issue occurred at 15.62 MHz. I would appreciate your assistance in determining whether my code is correct, as this simulation software is crucial for my project. I would also like to share my code for your review if you have some time to look at it and provide your valuable suggestions. Thank you for your attention. The code: RUN_SIMULATION = true; % ========================================================================= % 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 = 1; % [grid points] % set total number of grid points not including the PML Nx = 256*2 - 2 * pml_x_size; % [grid points] Ny = 128*2 - 2 * pml_y_size; % [grid points] Nz = 2; % [grid points] %128 - 2 * pml_z_size; x= 40e-3; dx = x / Nx; dy = dx; 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 c0 = 1540; % [m/s] rho0 = 1000; % [kg/m^3] % medium.alpha_mode = 'no_dispersion'; medium.alpha_coeff = 0.5; % [dB/(MHz^y cm)] medium.alpha_power = 1.0; % create the time array t_end = (Nx * dx) * 2.2 / c0; % [s] kgrid.makeTime(c0, [], t_end); % ========================================================================= % DEFINE THE INPUT SIGNAL % ========================================================================= % define properties of the input signal source_strength = 1e6; % [Pa] tone_burst_freq = 15.62e6; % [Hz] 7.8 MHz, 3.47 MHz tone_burst_cycles = 4; % 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 ./ (c0 * rho0)) .* input_signal; % ========================================================================= % DEFINE THE ULTRASOUND TRANSDUCER % ========================================================================= % physical properties of the transducer transducer.number_elements = 32; % total number of transducer elements transducer.element_width = 2; % width of each element [grid points] transducer.element_length = 1; %24; % 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 = c0; % sound speed [m/s] % transducer.focus_distance = Inf; %40e-3; % focus distance [m] % transducer.elevation_focus_distance = Inf; %19e-3; % focus distance in the elevation plane [m] transducer.steering_angle = 0; % steering angle [degrees] % apodization transducer.transmit_apodization = 'Hanning'; transducer.receive_apodization = 'Rectangular'; % define the transducer elements that are currently active number_active_elements = 32; transducer.active_elements = ones(transducer.number_elements, 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 THE MEDIUM PROPERTIES % ========================================================================= % define a large image size to move across number_scan_lines = 96; Nx_tot = Nx; Ny_tot = Ny + number_scan_lines * transducer.element_width; Nz_tot = Nz; % define a random distribution of scatterers for the medium background_map_mean = 1; background_map_std = 0.008; background_map = background_map_mean + background_map_std * randn([Nx_tot, Ny_tot, Nz_tot]); sound_speed_map = c0 * ones(Nx_tot, Ny_tot, Nz_tot) .* background_map; density_map = rho0 * ones(Nx_tot, Ny_tot, Nz_tot) .* background_map; % RUN THE SIMULATION % ========================================================================= % preallocate the storage scan_lines = zeros(number_scan_lines, kgrid.Nt); % set the input settings input_args = {... 'PMLInside', false, 'PMLSize', [pml_x_size, pml_y_size, pml_z_size], ... 'DataCast', DATA_CAST, 'DataRecast', true, 'PlotSim', false}; % run the simulation if set to true, otherwise, load previous results from % disk h = waitbar(0,'Please wait...'); if RUN_SIMULATION % set medium position medium_position = 1; % loop through the scan lines for scan_line_index = 1:number_scan_lines scan_line_index waitbar(scan_line_index/number_scan_lines,h) % update the command line status disp(''); disp(['Computing scan line ' num2str(scan_line_index) ' of ' num2str(number_scan_lines)]); % load the current section of the medium medium.sound_speed = sound_speed_map(:, medium_position:medium_position + Ny - 1, :); medium.density = density_map(:, medium_position:medium_position + Ny - 1, :); % run the simulation sensor_data = kspaceFirstOrder3D(kgrid, medium, transducer, transducer, input_args{:}); % extract the scan line from the sensor data scan_lines(scan_line_index, :) = transducer.scan_line(sensor_data); % update medium position medium_position = medium_position + transducer.element_width; end % save the scan lines to disk save HomogeneousTriaNew_scan_lines.mat; else % load the scan lines from disk load ('HomogeneousReferenceNew_scan_lines.mat'); end scan_lines_saved = scan_lines; scan_lines = scan_lines_saved;