http://www.k-wave.org/forum/topic/unexpected-peak-valleys-appeared-along-dimension-of-sensors Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:43:27 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/unexpected-peak-valleys-appeared-along-dimension-of-sensors#post-8658 Wed, 09 Nov 2022 10:55:11 +0000 serieslover 8658@http://www.k-wave.org/forum/ <p>sorry for missing some of the codes, i post updated version with similar problem below.<br /> the intensity variation along sensor dimension.</p> <p>radius = 11; % mm<br /> dx = 0.05; % mm<br /> dy = 0.05; % mm<br /> Nx = 2 * radius / dx + 1;<br /> Ny = 2 * radius / dy + 1;<br /> zlength = 10; % mm<br /> dz = 0.1; % mm<br /> Nz = zlength / dz;</p> <p>% % generate k-wave grids<br /> kgrid = kWaveGrid(Nx, dx*1e-3, Ny, dy*1e-3);<br /> kgrid.Nt = 1000;<br /> kgrid.dt = 2.5e-8;</p> <p>% % % acoustic pressure<br /> gruneisen_parameter = 0.02;<br /> absorption_coefficient = 0.01*ones(Nx, Ny);<br /> absorption_coefficient(((Nx+1)/2-10):((Nx+1)/2+10), ((Ny+1)/2-10):((Ny+1)/2+10)) = 0.2;<br /> source.p0 = gruneisen_parameter * absorption_coefficient;<br /> source.p_mask = zeros(size(source.p0));<br /> source.p_mask(((Nx+1)/2-10):((Nx+1)/2+10), ((Ny+1)/2-10):((Ny+1)/2+10)) = 1;</p> <p>% % sound speed and medium density<br /> medium.sound_speed = 1501 * ones(Nx, Ny);<br /> medium.density = 1000 * ones(Nx, Ny);<br /> medium.sound_speed(((Nx+1)/2-10):((Nx+1)/2+10), ((Ny+1)/2-10):((Ny+1)/2+10)) = 1488;</p> <p>% % sensor settings<br /> num_sensor = 1024;<br /> sensormask_xy = makeCartCircle((radius-0.2)*1e-3, num_sensor);<br /> sensormask_xy = [sensormask_xy(1,129:end),sensormask_xy(1,1:128);sensormask_xy(2,129:end),sensormask_xy(2,1:128)];</p> <p>% % generate source data arrays<br /> zstopmargin = 0.5; % mm<br /> zstop = zlength / zstopmargin;<br /> % for i=1:zstop<br /> for i=fix(zstop/2):fix(zstop/2)<br /> sensor.mask = [sensormask_xy(1,:);sensormask_xy(2,:)];<br /> % sensor_data = kspaceFirstOrder2D(kgrid, medium, source, sensor,'PMLAlpha',0);<br /> sensor_data = kspaceFirstOrder2D(kgrid, medium, source, sensor);<br /> end<br /> figure,imshow(source.p0(:,:),[]),title('source.p0 2D')<br /> sdata_single = sensor_data;<br /> figure,imshow(sdata_single,[]),title('sensor_data 2D') </p> http://www.k-wave.org/forum/topic/unexpected-peak-valleys-appeared-along-dimension-of-sensors#post-8651 Tue, 08 Nov 2022 10:29:33 +0000 Bradley Treeby 8651@http://www.k-wave.org/forum/ <p>I can't run your code as <code>absorption_coefficient</code> isn't defined. If you're after details of how k-Wave works under the hood, you can take a look in the user manual. </p> http://www.k-wave.org/forum/topic/unexpected-peak-valleys-appeared-along-dimension-of-sensors#post-8635 Mon, 31 Oct 2022 10:23:36 +0000 serieslover 8635@http://www.k-wave.org/forum/ <p>I have simulated a small object in water grids. But i get repeated peak-valleys of simulated data along with sensor dimension.Also i have tried difference objects like sphere, horizontal rectangles resulting same problems.<br /> Here is the object image<br /> <br /> And here is the resulting sensor-timestep image<br /> <br /> Besides that i have tried to move the sensors order in sensor.mask circulatively, and i get the peak-valleys of simulated data also moved circulatively.<br /> I have no idea about this, and doubt is it concerned to the calculation procedures? below is the code</p> <p>radius = 11; % mm<br /> dx = 0.05; % mm<br /> dy = 0.05; % mm<br /> Nx = 2 * radius / dx + 1;<br /> Ny = 2 * radius / dy + 1;<br /> zlength = 10; % mm<br /> dz = 0.1; % mm<br /> Nz = zlength / dz;</p> <p>% % generate k-wave grids<br /> kgrid = kWaveGrid(Nx, dx*1e-3, Ny, dy*1e-3);<br /> kgrid.Nt = 1000;<br /> kgrid.dt = 2.5e-8;</p> <p>% % % acoustic pressure<br /> gruneisen_parameter = 0.02;<br /> source.p0 = gruneisen_parameter * squeeze(absorption_coefficient(:,:,Nz/2)) .* squeeze(grid_fluence(:,:,Nz/2)) * 1e3;</p> <p>% % sound speed and medium density<br /> medium.sound_speed = 1501 * ones(Nx, Ny);<br /> medium.density = 1000 * ones(Nx, Ny);</p> <p>% % sensor settings<br /> num_sensor = 1024;<br /> sensormask_xy = makeCartCircle((radius-0.2)*1e-3, num_sensor);<br /> sensormask_xy = [sensormask_xy(1,129:end),sensormask_xy(1,1:128);sensormask_xy(2,129:end),sensormask_xy(2,1:128)];</p> <p>% % generate source data arrays<br /> zstopmargin = 0.5; % mm<br /> zstop = zlength / zstopmargin;<br /> % for i=1:zstop<br /> for i=fix(zstop/2):fix(zstop/2)<br /> sensor.mask = [sensormask_xy(1,:);sensormask_xy(2,:)];<br /> % sensor_data = kspaceFirstOrder2D(kgrid, medium, source, sensor,'PMLAlpha',0);<br /> sensor_data = kspaceFirstOrder2D(kgrid, medium, source, sensor);<br /> end<br /> figure,imshow(source.p0(:,:),[]),title('source.p0 2D')<br /> sdata_single = sensor_data;<br /> figure,imshow(sdata_single,[]),title('sensor_data 2D') </p>