k-Wave

1. jr20
   

   Member
   Joined: Mar '20
   Posts: 5

   Hi all,

   I want to perform coherent plane-wave compounding. The idea is that you transmit plane waves at different angles and then sum them coherently to increase SNR, maintaining high frame rates. I am using the built-in transducer class. I have an idea on how to perform the angled transmission and an idea on how to transmit unfocused waves:

   1. To perform angled transmissions, I would set the focus_distance = 0 and steering_angle = theta, where theta would be an angle that would change for each acquisition, say -30:3:30 degrees. This would allow performing the transmissions in the correct directions.

   2. To perform unfocused transmissions, I simply set focus_distance = inf or some very high number.

   Now, I suppose you can see the problem. focus_distance must be 0 to transmit in the correct direction but must be inf to transmit an unfocused wave.

   Is there any other way to rotate the transducer while maintaining the focus_distance = inf? Or a different way to transmit an unfocused/diverging/planar wave?

   If my explanation was not clear, please check Fig.1 in the following article, I believe this illustration is quite clear to understand the type of transmission I wish to perform:

   J. Porée, D. Posada, A. Hodzic, F. Tournoux, G. Cloutier and D. Garcia, "High-Frame-Rate Echocardiography Using Coherent Compounding With Doppler-Based Motion-Compensation," in IEEE Transactions on Medical Imaging, vol. 35, no. 7, pp. 1647-1657, July 2016. (https://ieeexplore.ieee.org/document/7398090)

   Posted 4 years ago #

2. Bradley Treeby
   

   Developer
   Joined: Mar '10
   Posts: 1,643

   Hi jr20,

   You can send an unfocused angled transmit by setting the focus distance to infinite and giving an angle. For example, open the Simulating Ultrasound Beam Patterns Example and set:

   transducer.focus_distance = inf;              % focus distance [m]
   transducer.elevation_focus_distance = inf;    % focus distance in the elevation plane [m]
   transducer.steering_angle = 20;               % steering angle [degrees]

   Brad

   Posted 4 years ago #

3. manik
   

   Member
   Joined: Jan '21
   Posts: 3

   Hi all,
   I am trying to do the same, but how to get all RF signal, simulation only give one RF line which is average of signal received by all elements

   Posted 2 years ago #

4. bencox
   

   Developer
   Joined: Mar '10
   Posts: 292

   Hi manik, Define your detector array elements as separate sensors.
   Best wishes
   Ben

   Posted 2 years ago #

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