k-Wave

1. tim_man
   

   Member
   Joined: Nov '12
   Posts: 3

   Dear Dr. Treeby and Dr. Cox,

   I use k-wave to simulate an absorbing sphere in 2D (homogeneous medium) using the kspaceFirstOrder2D function with a semicircular sensor centered on the grid.
   I'm considering about the negative part of the photoacoustic signal. Does it make sense to you, the average negative part of the pressure from all the sensor's elements to be in absolute value bigger than the positive part? Let me know if you need futher information or/and a plot of the signal.

   Thank you in advance.
   Best Regards,
   Tim

   Posted 11 years ago #

2. Bradley Treeby
   

   Developer
   Joined: Mar '10
   Posts: 1,643

   Hi Tim,

   I'm not sure I completely follow what you mean. Do you mean comparing the results of:

   mean(sensor_data(sensor_data > 0))
   mean(sensor_data(sensor_data < 0))

   Also, is your output data summed or averaged across your semicircular sensor?

   Brad.

   Posted 11 years ago #

3. tim_man
   

   Member
   Joined: Nov '12
   Posts: 3

   Hi Dr. Treeby,

   apologies for the delay.

   The output data averaged across the sensor's elements result to the shape of the pressure profile as you can see here: http://imageshack.com/a/img191/2164/4x4d.png

   Thank you - Best Regards,
   Tim

   Posted 11 years ago #

4. Bradley Treeby
   

   Developer
   Joined: Mar '10
   Posts: 1,643

   Hi Tim,

   I think that looks ok. If you look in Fig. 7 in [1], for a homogeneous cylindrical absorber with a delta function pulse, the magnitude of the peak negative pressure is greater than the magnitude of the peak positive pressure.

   Brad.

   [1] Hoelen, C.G.A., de Mul, F.F.M., 1999. A new theoretical approach to photoacoustic signal generation. J. Acoust. Soc. Am. 106, 695–706.

   Posted 11 years ago #

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