k-Wave

1. lishine
   

   Member
   Joined: Jul '19
   Posts: 4

   i often use points to make a bowl to form a focus transducer,and scan it. But it is so ....so hard!

   Posted 4 years ago #

2. Bradley Treeby
   

   Developer
   Joined: Mar '10
   Posts: 1,640

   HI lishine,

   We are working on a new class called kWaveArray that makes it easy to specify multi-element transducers (sources or sensors). We have a beta version, and we plan for this to be out with the next release. In the meantime, if you need to make a bowl, you could look at the makeBowl function.

   Brad.

   Posted 3 years ago #

3. tiagodourado
   

   Member
   Joined: Oct '17
   Posts: 9

   Thanks, Bradley for your help once again. Finally, could you indicate which example in k-wave works with this processing?

   Posted 10 months ago #

4. Bradley Treeby
   

   Developer
   Joined: Mar '10
   Posts: 1,640

   See the “ Modelling Plane Piston And Focused Bowl Transducers Example”.

   Posted 10 months ago #

5. leRequin
   

   Inactive
   Joined: Aug '23
   Posts: 2

   I had a similar issue. I need to simulate a phased-array bowl transducer with equidistant element spacing rather than a random array. More specifically, an algorithm for finding equidistant points on a 2-sphere. I wrote a short function that works relatively well for simple simulations but requires the number of elements to be perfect squares and needs to be improved. The most challenging part was finding how to rotate the elements to the focal point, which I eventually arrived at by trial and error. Maybe someone can provide more insight into making the points truly equidistant or how to calculate the rotation angles.

   Here are a few papers and algorithms discussing potential methods:
   1. Deserno. How to generate equi-distributed points on the surface of a sphere. If Polzmerforshung. 2004
   2. Algorithm. https://www.bogotobogo.com/Algorithms/uniform_distribution_sphere.php.
   3. S^2 sampling toolbox. Anton Semechko. Matlab File Exchange.
   4. mathworks.com/matlabcentral/answers/353-uniform-distribution-of-n-points-within-a-sphere

   function [px,py,pz,pa,pe, karray, source] = make_phased_array_bowl_transducer(source_focus, element_num, kgrid, element_width, element_length, translation, rotation)
   s1 = (pi*source_focus)/(sqrt(element_num));
   s2 = (pi*source_focus)/(sqrt(element_num)+1);
   angle1 = s1/source_focus;
   angle2 = s2/source_focus;
   ca1 = 0;
   ca2 = angle2;
   cnt=1;
   for i=1:sqrt(element_num)
   for j=1:sqrt(element_num)
   px(cnt) = source_focus*sin(ca2)*cos(ca1);
   py(cnt) = source_focus*sin(ca2)*sin(ca1);
   pz(cnt) = -source_focus*cos(ca2);
   pa(cnt) = 180/pi*ca1-90;
   pe(cnt) = 180/pi*ca2;
   ca1 = ca1 + angle1;
   cnt=cnt+1;
   end
   ca2 = ca2 + angle2;
   ca1=0;
   end
   figure
   plot3(px,py,pz,'.')

   karray = kWaveArray('BLITolerance', 0.05, 'UpsamplingRate', 10);
   for ind = 1:element_num
   karray.addRectElement([px(ind), py(ind), pz(ind)], element_width, element_length, [pe(ind),0,pa(ind)]);
   end
   karray.setArrayPosition(translation, rotation)
   source.p_mask = karray.getArrayBinaryMask(kgrid);

   end

   -Ryan

   Posted 7 months ago #

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