k-Wave User Forum » Topic: Defining Ultrasound Transducer example

k-Wave User Forum » Topic: Defining Ultrasound Transducer example http://www.k-wave.org/forum/topic/defining-ultrasound-transducer-example Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 00:09:09 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php Anthony on "Defining Ultrasound Transducer example" http://www.k-wave.org/forum/topic/defining-ultrasound-transducer-example#post-5139 Fri, 10 Jul 2015 13:12:16 +0000 Anthony 5139@http://www.k-wave.org/forum/ Hi Suryakant, It is a problem of matrix size when you write : <pre><code>imput_signal = (source_strength./(medium.sound_speed*medium.density)).*input_signal;</code></pre> First of all, you should use .* instead of * to multiply term by therm the density and the sound speed... but I don't exactly get what you are trying to do (I am not familiar with the use of the transducer class): if the input signal is the same at every point of your transducer, should'nt you set your source term as a matrix of size [1,Nt] (or [Nt,1], I don't remember), with Nt the number of time steps? If the signal is different at every point of your transducer (phased array for example), I guess your source term should be of size [Ntr,Nt] (or [Nt, Ntr], I don't remember), with Ntr the number of points in your transducer. Your definition of the transducer does not seem correct. Once again I am not familiar with the transducer class as I do everything manually but look at the help of the function <code>makeTransducer</code> to define its properties. I am not sure you are allowed to manually set <code>transducer.number_elements</code> and the other properties directly. You can probably find the other examples helpful too. Good luck :-) Anthony PS: by the way, you have a little typo in your code : "imput_signal" instead of "input_signal". Suryakant on "Defining Ultrasound Transducer example" http://www.k-wave.org/forum/topic/defining-ultrasound-transducer-example#post-5137 Thu, 09 Jul 2015 19:48:25 +0000 Suryakant 5137@http://www.k-wave.org/forum/ We tried running the aforementioned example however we were getting a few errors The first error being that it says "error using *" in the following input_signal = (source_strength./(medium.sound_speed*medium.density)).*inputsignal Can anyone please help us on how to correct this error % defining an ultrasound sognle frequency toneburst sample_frequency =20000000; signal_frequency =1000000; num_cycles = 10; Nx =128; Ny =128; Nz =128; dx = .00001; dy = .00001; dz = .00001; kgrid = makeGrid(Nx,dx,Ny,dy,Nz,dz); kgrid.t_array = makeTime(kgrid,1500); medium.sound_speed =1500*ones(Nx,Ny,Nz); medium.sound_speed(1:Nx/2,:,:)=1800; medium.density =1000*ones(Nx,Ny,Nz); medium.density(:,Ny/4:end, :)=1200; signal = toneBurst(sample_frequency,signal_frequency,num_cycles); toneBurst(sample_frequency,signal_frequency,num_cycles,'Plot',true); source_strength = 1*10^6; tone_burst_freq = .5*10^6; tone_burst_cycles = 5; input_signal = toneBurst(1/kgrid.dt,tone_burst_freq,tone_burst_cycles); imput_signal = (source_strength./(medium.sound_speed*medium.density)).*input_signal; transducer.number_elements = 64; transducer.element_width =1 ; transducer.element_length = 12; transducer.element_spacing = 0; transducer.radius = inf; transducer_width = transducer.number_elements*transducer.element_width + (transducer.number_elements -1)*transducer.element_spacing; transducer.position = round([1,32-transducer_width/2,32-transducer.element_length/2]); transducer.sound_speed = 1540; transducer.focus_distance = 20*10^-3; transducer.elevation_focus_distance = 19*10^-3; transducer.steering_angle = 0; transducer.transmit_apodization = 'Rectangular'; transducer.receive_apodization = 'Rectangular'; transducer.active_elements = zeros(transducer.number_elements,1); transducer.active_elements(21:52) = 1; transducer.input_signal = input_signal; transducer = makeTransducer(kgrid,transducer); [sensor_data] = kspaceFirstOrder3D(kgrid,medium,transducer, sensor,input_args{:});