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tjk9501

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- TL;DR Summary
- Confronted with coding problems in ultrasound diffraction tomography. Please tell me how to perform the correct coding to achieve 2D imaging.

I'm currently working on an ultrasound diffraction tomography algorithm that incorporates a BentRay based Time of Flight approach. In the experimental setup, a circular transducer array is deployed around the region of interest, with each sensor actuated sequentially to collect acoustic time-domain signals. This setup allows us to acquire time-domain signals for all transmitter-receiver combinations, then use FFT to extract frequency domain components.

A critical step in image reconstruction involves calculating the beamforming value I_BF(z) at each pixel, where z=(z_x,z_y) defines the pixel position in the 2D plane. According to equation (13) from my reference material, this requires a double integral over both source and receiver coordinates in the plane, where Gw(x,z) represents the Green's function. However, ψs(x,y) represents the scattered wavefield, which we can only measure at discrete receiver positions. This limitation has led to confusion about how to compute the integral accurately.

Currently, my approach to calculate I_BF(z) is as follows:

I am aware that this method does not account for the scattered field at points not located at the transducer locations. My questions are:

What are the potential pitfalls of my current method?

How can I improve my code to more accurately perform the necessary integrals, considering the limitations of the measured scattered field?

Thank you!

A critical step in image reconstruction involves calculating the beamforming value I_BF(z) at each pixel, where z=(z_x,z_y) defines the pixel position in the 2D plane. According to equation (13) from my reference material, this requires a double integral over both source and receiver coordinates in the plane, where Gw(x,z) represents the Green's function. However, ψs(x,y) represents the scattered wavefield, which we can only measure at discrete receiver positions. This limitation has led to confusion about how to compute the integral accurately.

Currently, my approach to calculate I_BF(z) is as follows:

Code:

```
I_BF = zeros(Nx, Ny);
for i = 1:Nsrc
for j = 1:Nrec
for ipos = 1:Nx
% Calculate psi_s(i, j)
for jpos = 1:Ny
Gw_src = Gw(xx(ipos), yy(jpos), xsrc(i), ysrc(i));
Gw_rec = Gw(xx(ipos), yy(jpos), xrec(j), yrec(j));
I_BF(ipos, jpos) = I_BF(ipos, jpos) + psi_s(i, j) / (Gw_src * Gw_rec);
end
end
end
end
```

What are the potential pitfalls of my current method?

How can I improve my code to more accurately perform the necessary integrals, considering the limitations of the measured scattered field?

Thank you!

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