k-Wave

1. peiliu
   

   Member
   Joined: Nov '18
   Posts: 5

   Hello，
   Thank you for your toolbox.And I'm a student in high school.I'm confusing how to generate a cylinfrical in 3D Kgrid? Itry to refer the planar transducer but failed.Can you help me.
   Thanks in advance!

   Posted 5 years ago #

2. Anthony
   

   Member
   Joined: Apr '13
   Posts: 96

   Hi,

   I am using k-Wave since a few years, so there might be quicker ways to do it now, but you can define transducers of arbitrary shape by making a binary mask.

   See the example entitled "Simulating Transducer Field Patterns Example".

   A simple way of making a cylinder is, for example, to use makeArc and then extrude the arc:

   clearvars
   close all
   clc
   
   % Transducers parameters
   R = 11; % curvature radius (unit: grid points)
   L = 21; % cylinder length (unit: grid points)
   diameter = 15; % aperture diameter (length of line connecting arc endpoints) (unit: grid points)
   
   % Binary mask initialisation
   Nx = 25; % my example only works properly if it is odd
   Ny = 25; % my example only works properly if it is odd
   Nz = 35; 
   
   %% Arc in 2D
   arcMask = makeArc([Nx, Nz], [ceil(Nx/2) 2], R, diameter, [ceil(Nx/2) Nz]);
   
   figure(1)
   clf
   imagesc(arcMask);
   axis image
   
   %% Axis permutation (I assume a main propagation axis along Z and a main cylinder axis along Y)
   arcMask = reshape(arcMask,[Nx,1,Nz]);
   source.p_mask = repmat(arcMask,[1 Ny 1]); % extrusion
   source.p_mask(:,1:(Ny-L)/2,:) = 0; % crop the left border
   source.p_mask(:,Ny-(Ny-L)/2+1:Ny,:) = 0; % crop the right border
   
   %% 3D display
   voxelPlot(source.p_mask); % just for fun

   Posted 5 years ago #

3. Anthony
   

   Member
   Joined: Apr '13
   Posts: 96

   PS : By the way I made the code easy to read but, of course, the use of bsxfun() is much more elegant than repmat() ;-)

   %% Axis permutation (I assume a main propagation axis along Z and a main cylinder axis along Y)
   arcMask = reshape(arcMask,[Nx,1,Nz]);
   extrusionVector = [zeros(1,(Ny-L)/2),ones(1,L),zeros(1,(Ny-L)/2)];
   source.p_mask = bsxfun(@times,arcMask,extrusionVector);

   Posted 5 years ago #

4. peiliu
   

   Member
   Joined: Nov '18
   Posts: 5

   oh,thank you very much!For some reason I didn't see your reply until now.I have solved the problem.But thank you all the same.Your suggestion has given me a lot of inspiration,thank you a lot~

   Posted 5 years ago #

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