http://www.k-wave.org/forum/topic/focus-point Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:39:14 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/focus-point#post-672 Mon, 06 Aug 2012 10:09:14 +0000 Bradley Treeby 672@http://www.k-wave.org/forum/ <p>Hi cdelu,</p> <p>Sorry for the delay in replying to your post. Using the <code>kWaveTransducer</code> class, the beam can only be steered within a 2D plane, similar to conventional diagnostic ultrasound transducers. In this case, the parameters <code>focus_distance</code> and <code>steering_angle</code> set the focus position within the x-y plane. </p> <p>The parameter <code>elevation_focus_distance</code> controls the focusing in the elevation or x-z plane. For most transducers, this focus distance is fixed and physically occurs due to the shape of the transducer elements or a lens.</p> <p>If you are interested in a more general simulation, I would define the source mask and signals directly, rather than using the <code>kWaveTransducer</code> class. For example, you could define <code>source.p_mask</code> to be a rectangle with 'G' grid points, define <code>source.p</code> to have G time series, then delay the time signal associated with each grid point based on its distance to the focus point.</p> <p>I hope that answers your questions,</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/focus-point#post-641 Fri, 27 Jul 2012 09:51:43 +0000 cdelu 641@http://www.k-wave.org/forum/ <p>Hello,</p> <p>I am also a bit new to kWave, so my apologies for this low-level question. </p> <p>I am trying to define a transducer so that I can focus my signal at a certain point given by the coordinates (x0,y0,z0). Assuming the waves are travelling in x-direction, I assumed my focus_distance will be given by x0, the elevation_focus_distance by z0 and the steering_angle can be computed from y0. After running some simulations, I noticed that these assumptions are not necessarily the right ones. Can someone please explain what is the right approach?</p> <p>Thank you in advance. </p>