Hi, I'm a student from Norway.
In my master thesis need I to have data from scattering of plane wave, with a given steering angle. And with assumption that the medium has different sound speed maps in given regions.
I tried to modify B-mode transducer example by setting focus and elevation focus to inf.
And some modification on how to set up the medium.
My goal is too have data that is just a speckle pattern where you cant dissolve any region even if some regions have different SOS.
And to get the code to run, I had to define a density_map. Is this correct to include? Given that I want to characterize my region whit different SOS ?
Is this possible to generate?
My changes to the code:
% properties used to derive the beamforming delays
transducer.focus_distance = inf;
transducer.elevation_focus_distance = inf;
transducer.sound_speed = c0; % sound speed [m/s]
transducer.steering_angle = 0; % steering angle [degrees]
% define a random distribution of scatterers for the medium
background_map = 75*randn([Nx_tot, Ny_tot, Nz_tot]);
% define a sligthly translated data for region whit different SOS.
scattering_c0 = c0 + 25 + background_map;
scattering_rho0 = scattering_c0/1.5;
% define properties
sound_speed_map = c0*ones(Nx_tot, Ny_tot, Nz_tot).*background_map;
density_map = rho0*ones(Nx_tot, Ny_tot, Nz_tot).*background_map;
% define a sphere for a scattering region whit different SOS.
radius = 4.5e-3; % [m]
x_pos = 20e-3; % [m]
y_pos = 20e-3; % [m]
scattering_region1 = makeBall(Nx_tot, Ny_tot, Nz_tot, round(x_pos/dx), round(y_pos/dx), Nz_tot/2, round(radius/dx));
% assign region
sound_speed_map(scattering_region1 == 1) = scattering_c0(scattering_region1 == 1);
density_map(scattering_region1 == 1) = scattering_rho0(scattering_region1 == 1);
I also had to set
medium.sound_speed_ref = 1540;
otherwise It was like 639876.