k-Wave

1. ehooi
   

   Member
   Joined: Jul '19
   Posts: 1

   Hi all,

   According to the example files:
   % physical properties of the transducer
   transducer.number_elements = 72; % total number of transducer elements
   transducer.element_width = 1; % width of each element [grid points]
   transducer.element_length = 12; % length of each element [grid points]
   transducer.element_spacing = 0; % spacing (kerf width) between the elements [grid points]
   transducer.radius = inf; % radius of curvature of the transducer [m]

   which to me, suggests that the US transducer can only be set up based on grid points. Is there a way to set this up base on the physical dimensions? For example, I have a transducer with width of 150e-6 m. Setting transducer.element_width would have given me dx of 150e-6, which isn't efficient for a domain that is 16cm large.

   Thank you.

   Posted 4 years ago #

2. vich
   

   Member
   Joined: Jul '19
   Posts: 19

   As far as I know, your suspicion is correct, all abstractions that k-Wave provides ultimately degenerate into references to individual voxels (or pixels). Physical dimensions are divided by the dx/dy/dz lengths and rounded to an integer (I am not sure right now about the specific rounding algorithm(s) that is used).

   Techniques for injecting a pressure source within a volume smaller than one voxel might include some sort of spatial averaging, but I am not sure if that is a correct approach. Even if it is, this kind of procedure is only possible when your amount of information decreases, i.e. you know the precise location of the pressure source but represent it in a coarser grid. This means that there will be no way to use the transducer as a sensor, since you will not know the pressure distribution within any given voxel anymore.

   This is what came to my mind, but I may have missed something...

   Posted 4 years ago #

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