k-Wave

1. marjanbn
   

   Member
   Joined: Jun '18
   Posts: 7

   Dear k-Wave developers,

   I am trying to generate a B-mode image for a phantom with two inclusions (circular shape) using "Simulating B-mode Ultrasound Images Example".

   The center of the first inclusion, having a diameter of 5 mm, locates at the depth of 10 mm, and the other one, having a diameter of 10 mm, locates at the depth of 25 mm.

   If I define the focus distance at 10 mm, I will get the first inclusion exactly circular and almost lost the second inclusion (which makes sense), and the same goes for the second inclusion if I define the focus distance at 25 mm. However, if I select a focus distance between 13 to 18 mm, I will get the B-mode image with oval inclusions, whereas in practice, using an ultrasound machine, we get the B-mode image with circular inclusions. How can I get the circular shape for inclusions in the simulation?

   Please find below some figures for clarification:
   https://photos.app.goo.gl/JkEtfgU1SwdAwzCt7

   P.S., I tried playing with the apodization settings, e.g., changing the transmit_apodization to 'Gaussian' but it didn't help.

   Thanks in advance for your time answering my question, and thanks for the great toolbox.

   Best,
   Marjan

   Posted 3 years ago #

2. Bradley Treeby
   

   Developer
   Joined: Mar '10
   Posts: 1,643

   Hi Marjan,

   The "smearing" of the circular inclusion is a result of the finite beam width. This is affected by both the imaging physics (the width of the focused beam on transmit) and the beam-forming on receive. My guess is there is nothing wrong with your simulation, just that the experiment used better signal processing (e.g., dynamic receive beamforming / multi-zone transmit) and potentially a higher frequency (which gives a narrower beam-width). You could look USTB if you want to play around with different approaches to beam-forming / image formation.

   Hope that helps,

   Brad.

   Posted 3 years ago #

3. marjanbn
   

   Member
   Joined: Jun '18
   Posts: 7

   Hi Dr. Treeby,

   Thanks for your info. It helps a lot.

   Best,
   Marjan

   Posted 3 years ago #

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