http://www.k-wave.org/forum/topic/ultrasound-for-1mm-per-voxel Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 03:01:38 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/ultrasound-for-1mm-per-voxel#post-7271 Thu, 05 Mar 2020 17:57:35 +0000 ninasnum 7271@http://www.k-wave.org/forum/ <p>Nevermind, I realize I didn't update the signal focus distance. Thanks :) </p> http://www.k-wave.org/forum/topic/ultrasound-for-1mm-per-voxel#post-7263 Wed, 04 Mar 2020 20:34:43 +0000 ninasnum 7263@http://www.k-wave.org/forum/ <p>Hi,<br /> I'm trying to run the B-mode ultrasound images example with different parameters. I wanted to see how the ultrasound would look for a 100x100x100 voxel grid with 1 voxel = 1mm.<br /> I also modified the transducer to have 25 active elements instead of 32 and updated the position/radius of the balls.</p> <p>Here's my modified lines:<br /> <pre><code>% 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 = 256 - 2 * pml_x_size; % [grid points] %Ny = 128 - 2 * pml_y_size; % [grid points] %Nz = 128 - 2 * pml_z_size; % [grid points] Nx = 140 - 2 * pml_x_size; % [grid points] Ny = 120 - 2 * pml_y_size; % [grid points] Nz = 120 - 2 * pml_z_size; % [grid points] % set desired grid size in the x-direction not including the PML %x = 40e-3; % [m] x = 100e-3; % [m] % calculate the spacing between the grid points dx = x / Nx; % [m] dy = dx; % [m] dz = dx; % [m] . . . % physical properties of the transducer %transducer.number_elements = 32; % total number of transducer elements transducer.number_elements = 25; % total number of transducer elements transducer.element_width = 2; % width of each element [grid points] %transducer.element_length = 24; % length of each element [grid points] transducer.element_length = 25; % 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] . . . % define the transducer elements that are currently active %number_active_elements = 32; number_active_elements = 25; transducer.active_elements = ones(transducer.number_elements, 1); . . . % define a large image size to move across number_scan_lines = 100; . . . zPos = 50; % define a sphere for a highly scattering region %radius = 6e-3; % [m] %x_pos = 27.5e-3; % [m] %y_pos = 20.5e-3; % [m] radius = 10; % [mm] x_pos = 75; % [mm] y_pos = 20.5; % [mm] %scattering_region1 = makeBall(Nx_tot, Ny_tot, Nz_tot, round(x_pos/dx), round(y_pos/dx), zPos, round(radius/dx)); scattering_region1 = makeBall(Nx_tot, Ny_tot, Nz_tot, x_pos, y_pos, zPos, radius); % assign region sound_speed_map(scattering_region1 == 1) = scattering_c0(scattering_region1 == 1); density_map(scattering_region1 == 1) = scattering_rho0(scattering_region1 == 1); % define a sphere for a highly scattering region %radius = 5e-3; % [m] %x_pos = 30.5e-3; % [m] %y_pos = 37e-3; % [m] radius = 15; % [mm] x_pos = 30.5; % [mm] y_pos = 37; % [mm] %scattering_region2 = makeBall(Nx_tot, Ny_tot, Nz_tot, round(x_pos/dx), round(y_pos/dx), zPos, round(radius/dx)); scattering_region2 = makeBall(Nx_tot, Ny_tot, Nz_tot, x_pos, y_pos, zPos, radius); % assign region sound_speed_map(scattering_region2 == 1) = scattering_c0(scattering_region2 == 1); density_map(scattering_region2 == 1) = scattering_rho0(scattering_region2 == 1); % define a sphere for a highly scattering region %radius = 4.5e-3; % [m] %x_pos = 15.5e-3; % [m] %y_pos = 30.5e-3; % [m] radius = 10; %[mm] x_pos = 50; %[mm] y_pos = 30.5; %[mm] %scattering_region3 = makeBall(Nx_tot, Ny_tot, Nz_tot, round(x_pos/dx), round(y_pos/dx), zPos, round(radius/dx)); scattering_region3 = makeBall(Nx_tot, Ny_tot, Nz_tot, x_pos, y_pos, zPos, radius);</code></pre> <p>But when I run it, I get nearly a pure black image for the b-mode image.<br /> It also looks like the original signal is also shifted.<br /> Does my spacing for the grid (dx, dy,dz) effect the signal? If so, how should I determine how to adjust for it? </p>