k-Wave

1. TJWU
   

   Member
   Joined: Sep '11
   Posts: 2

   Hi

   I am studying on a photoacoustic tomograohy project in Graduate of Mechanical and Electrical Engineering Institution in Taiwan.

   I had a sinogram (.bmp) photo,which collected from my experiment.

   By using a Nd:YAG pumped laser to excited my specimen and a focused ultrasound transducer to do a 360 degrees circular scan around it in a water tank.

   A rotational step size ,rotational radius; transducer central frequency; specimen's parameter; laser energy, pulse duration time, repetition rate are known.

   So I have a series time domain data from scanning, and the sinogram photo.

   The problem is how can I reconstructed the original image from the sinogram photo by using the k-wave toolbox.

   I tried to rewrite the command of example 'kspaceFirstOrder2D' , but it's really hard to understand most of them.

   Please tell me how can I solve this problems.

   Thanks!

   Leo

   Posted 12 years ago #

2. bencox
   

   Developer
   Joined: Mar '10
   Posts: 285

   Dear Leo,

   Have you tried something similar to the 2D Time Reversal Reconstruction For A Circular Sensor Example?

   You will need to make sure the detector points stored in sensor.mask are set to the positions of your detectors, and sensor.time_reversal_boundary_data holds the matrix of time series you recorded. Study the example (and the other time reversal reconstruction examples) if that's not clear.

   Regards,

   Ben

   Posted 12 years ago #

3. TJWU
   

   Member
   Joined: Sep '11
   Posts: 2

   Hi

   First I'm very appreciated your reply.

   Actually, I have tried the example of "2D time Reversal Reconstruction For A Circular Sensor", but there's still some question I can't understand.

   1.How can I define the initial pressure which generated by incident laser? The command describe the magnitude with "p0_magnitude = 2". "2" means what? and the unit is ?

   2.The command from kgrid, "Nx" and "Nz" are equal the pixel numbers of my sinogram?
   If I have a sinogram photo, it's size is 599*292, so that Nx is 599 and Nz is 292?

   3.I tried to load my sinogram photo into this example, but it can't work. Maybe I should confirm the contour of color map is matched? or something got wrong... Could you give me some advice?

   Thanks

   Posted 12 years ago #

4. bencox
   

   Developer
   Joined: Mar '10
   Posts: 285

   Hi Leo,

   I'm assuming that the individual lines that make up your sinogram are time series measurements of the acoustic pressure at detectors of known position. It is these individual time series that you need to allocate to particular sensor points during the time reversal image reconstruction. You don't need the forward modelling part: that is in the simulation just to generate data, but you already have the data. You want to set the source.p0 to be zero and associate your data with sensor.time_reversal_boundary_data, but you will need to think about how to do it! The sensor mask will need to contain the points of the sensors corresponding to the time series measurements in your data.

   I hope you can get it to work.

   Ben

   Posted 12 years ago #

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