http://www.k-wave.org/forum/topic/please-add-focus-transducer Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:08:39 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/please-add-focus-transducer#post-8903 Thu, 31 Aug 2023 18:20:16 +0000 leRequin 8903@http://www.k-wave.org/forum/ <p>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.</p> <p>Here are a few papers and algorithms discussing potential methods:<br /> 1. Deserno. How to generate equi-distributed points on the surface of a sphere. If Polzmerforshung. 2004<br /> 2. Algorithm. <a href="https://www.bogotobogo.com/Algorithms/uniform_distribution_sphere.php" rel="nofollow">https://www.bogotobogo.com/Algorithms/uniform_distribution_sphere.php</a>.<br /> 3. S^2 sampling toolbox. Anton Semechko. Matlab File Exchange.<br /> 4. mathworks.com/matlabcentral/answers/353-uniform-distribution-of-n-points-within-a-sphere</p> <p>function [px,py,pz,pa,pe, karray, source] = make_phased_array_bowl_transducer(source_focus, element_num, kgrid, element_width, element_length, translation, rotation)<br /> s1 = (pi*source_focus)/(sqrt(element_num));<br /> s2 = (pi*source_focus)/(sqrt(element_num)+1);<br /> angle1 = s1/source_focus;<br /> angle2 = s2/source_focus;<br /> ca1 = 0;<br /> ca2 = angle2;<br /> cnt=1;<br /> for i=1:sqrt(element_num)<br /> for j=1:sqrt(element_num)<br /> px(cnt) = source_focus*sin(ca2)*cos(ca1);<br /> py(cnt) = source_focus*sin(ca2)*sin(ca1);<br /> pz(cnt) = -source_focus*cos(ca2);<br /> pa(cnt) = 180/pi*ca1-90;<br /> pe(cnt) = 180/pi*ca2;<br /> ca1 = ca1 + angle1;<br /> cnt=cnt+1;<br /> end<br /> ca2 = ca2 + angle2;<br /> ca1=0;<br /> end<br /> figure<br /> plot3(px,py,pz,'.')</p> <p> karray = kWaveArray('BLITolerance', 0.05, 'UpsamplingRate', 10);<br /> for ind = 1:element_num<br /> karray.addRectElement([px(ind), py(ind), pz(ind)], element_width, element_length, [pe(ind),0,pa(ind)]);<br /> end<br /> karray.setArrayPosition(translation, rotation)<br /> source.p_mask = karray.getArrayBinaryMask(kgrid);</p> <p>end</p> <p>-Ryan </p> http://www.k-wave.org/forum/topic/please-add-focus-transducer#post-8830 Tue, 13 Jun 2023 19:44:46 +0000 Bradley Treeby 8830@http://www.k-wave.org/forum/ <p>See the “ Modelling Plane Piston And Focused Bowl Transducers Example”. </p> http://www.k-wave.org/forum/topic/please-add-focus-transducer#post-8824 Mon, 12 Jun 2023 15:36:32 +0000 tiagodourado 8824@http://www.k-wave.org/forum/ <p>Thanks, Bradley for your help once again. Finally, could you indicate which example in k-wave works with this processing? </p> http://www.k-wave.org/forum/topic/please-add-focus-transducer#post-7452 Fri, 01 May 2020 08:19:24 +0000 Bradley Treeby 7452@http://www.k-wave.org/forum/ <p>HI lishine,</p> <p>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 <code>makeBowl</code> function.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/please-add-focus-transducer#post-7419 Sun, 19 Apr 2020 13:38:15 +0000 lishine 7419@http://www.k-wave.org/forum/ <p>i often use points to make a bowl to form a focus transducer,and scan it. But it is so ....so hard! </p>