k-Wave User Forum » Topic: 3D reconstruction using a plane transducer

k-Wave User Forum » Topic: 3D reconstruction using a plane transducer http://www.k-wave.org/forum/topic/3d-reconstruction-using-a-plane-transducer Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 01:02:20 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php wang mengxiao on "3D reconstruction using a plane transducer" http://www.k-wave.org/forum/topic/3d-reconstruction-using-a-plane-transducer#post-6569 Mon, 20 Aug 2018 16:56:44 +0000 wang mengxiao 6569@http://www.k-wave.org/forum/ Hi Ben, I'm not sure if you can open link i post above. If not, you can try that link: <a href="https://pan.baidu.com/s/1gMtKVs5sQcqd1VcfTMqr-w" rel="nofollow">https://pan.baidu.com/s/1gMtKVs5sQcqd1VcfTMqr-w</a>. Thank you very much. Sincerely, Mengxiao wang mengxiao on "3D reconstruction using a plane transducer" http://www.k-wave.org/forum/topic/3d-reconstruction-using-a-plane-transducer#post-6568 Mon, 20 Aug 2018 16:25:45 +0000 wang mengxiao 6568@http://www.k-wave.org/forum/ Hi Ben, Here are the pictures i post: <a href="https://drive.google.com/drive/u/0/my-drive" rel="nofollow">https://drive.google.com/drive/u/0/my-drive</a>. Sincerely, Mengxiao bencox on "3D reconstruction using a plane transducer" http://www.k-wave.org/forum/topic/3d-reconstruction-using-a-plane-transducer#post-6567 Mon, 20 Aug 2018 10:44:51 +0000 bencox 6567@http://www.k-wave.org/forum/ Hi Mengxiao, To post a picture, some users have uploaded the picture to an image hosting site and then posted the link. Without seeing the pictures, I would guess you are seeing the effect of the limited view (the finite-sized aperture) of your transducer. Have a look at this paper for more details: <a href="https://aapm.onlinelibrary.wiley.com/doi/pdf/10.1118/1.1644531"> 'Reconstructions in limited-view thermoacoustic tomography' </a> Best wishes, Ben wang mengxiao on "3D reconstruction using a plane transducer" http://www.k-wave.org/forum/topic/3d-reconstruction-using-a-plane-transducer#post-6565 Fri, 17 Aug 2018 04:37:05 +0000 wang mengxiao 6565@http://www.k-wave.org/forum/ Hi dear bencox, Here is my code: %% define literals PML_size = 10; % size of the perfectly matched layer in grid points %% create the computational grid Nx = 120 - 2 * PML_size; % number of grid points in the x direction Ny = 120 - 2 * PML_size; % number of grid points in the y direction Nz = 120 - 2 * PML_size; % number of grid points in the z direction dx = 1.25e-3 ; % grid point spacing in the x direction [m] dy = 1.25e-3; % grid point spacing in the y direction [m] dz = 1.25e-3; % grid point spacing in the z direction [m] kgrid = kWaveGrid(Nx, dx, Ny, dy, Nz, dz); %% load the initial pressure distribution from an image and scale p0=importdata('C:\Users\WANG MENG XIAO\Desktop\TR_reconstruction\codes\initial_pressure.mat'); p0_binary=zeros(Nx,Ny,Nz); p0_binary(39:62,35:66,26:43)=p0; p0=p0_binary; %% assign to the source structure source.p0 = p0; %% define the properties of the propagation medium medium.sound_speed = 1500; % [m/s] medium.density=1000; % [kg/m^3] medium.alpha_coeff = 0.75; % power law absorption prefactor [dB/(MHz^y*cm)] medium.alpha_power = 1.5; % power law absorption exponent %% define a binary planar sensor sensor.mask = zeros(kgrid.Nx, kgrid.Ny, kgrid.Nz); sensor.mask(35:66,35:66,76) = 1; %% define frequence and bandwidth of sensor center_freq =1e6; % the center frequency of sensor(Hz) bandwidth = 100; % bandwidth 100% sensor.frequency_response = [center_freq, bandwidth]; %% create the time array t_end=sqrt((Nx*dx).^2 + (Ny*dy).^2 + (Nz*dz).^2)/medium.sound_speed; cfl = 0.3; dt = cfl*dx/medium.sound_speed; kgrid.t_array = 0:dt:t_end; %% set the input arguements input_args = {'PMLSize', PML_size, 'PMLInside', false, ... 'PlotPML', false, 'Smooth', false, 'PlotSim', true}; %% run the simulation sensor_data = kspaceFirstOrder3D(kgrid, medium, source, sensor, input_args{:}); %% ========================================================================= % RECONSTRUCT AN IMAGE USING TIME REVERSAL % ========================================================================= % remove the initial pressure field used in the simulation source = rmfield(source, 'p0'); % use the sensor points as sources in time reversal source.p_mask = sensor.mask; %% time reverse and assign the data %source.p=zeros(sum(source.p_mask(:)),kgrid.Nt); source.p = fliplr(sensor_data); % enforce, rather than add, the time-reversed pressure values source.p_mode = 'dirichlet'; % set the simulation to record the final image (at t = 0) sensor.record = {'p','p_final'}; % run the time reversal reconstruction p0_estimate = kspaceFirstOrder3D(kgrid, medium, source, sensor, input_args{:}); %% apply a positivity condition % p0_estimate.p_final = p0_estimate.p_final .* (p0_estimate.p_final > 0); % store the latest image estimate p0_1 = p0_estimate.p_final; The part that is close to and farther awway from the detectors have good reconstruction results. However, the middle part has bad results. I don't know how to post images. If you dont mind, would you tell me your email address so I can sent it to you? bencox on "3D reconstruction using a plane transducer" http://www.k-wave.org/forum/topic/3d-reconstruction-using-a-plane-transducer#post-6564 Fri, 17 Aug 2018 00:00:09 +0000 bencox 6564@http://www.k-wave.org/forum/ Hi Mengxiao, I'm afraid I don't understand your question. Can you post images, or some code? Thanks, Ben wang mengxiao on "3D reconstruction using a plane transducer" http://www.k-wave.org/forum/topic/3d-reconstruction-using-a-plane-transducer#post-6553 Thu, 16 Aug 2018 20:00:27 +0000 wang mengxiao 6553@http://www.k-wave.org/forum/ Hi all, I have a question. Why is 3D reconstruction okey to be away from the detector and close to it, but not to be in the middle when i used a plane transducer? Thank you very much. Mengxiao