Image_syn_data.zip_beamforming_image syn官网_near field

% This m-file creates a simulated group of time-series' due to two perfect % point reflectors located at a user-defined location in the field of % interest. clear all; close all; % Material properties c=1500; % Sound speed in medium of interest, (m/s) % Pulse properties fc=5e6; % Center frequency of pulse, (Hz) lam=c/fc; % Wavelength at center frequency, (m) bw=0.5; % Fractional bandwidth, () % Define receive array p=lam/2; % Pitch between elements N=128; % Number of receivers L_array=(N-1)*p; % Length of array, (m) X=zeros(1,N); X_sum=0; for m=1:N X(m)=(m-1)*p; end % Define maximum imaging depth r_max=5e-2; % Maximum depth inspected, (m) t_max=2*sqrt(r_max^2+(L_array/2)^2)/c; % Maximum time to listen, (s) % Create time vector dt=1/(25*fc); % Time increment for data aquisition; (s) t=0:dt:t_max; % Locate reflector Xr1=L_array/1.5; % Reflector 1 coordinates as functions of the array Yr1=r_max/6; % & max depth dimensions Xr2=L_array/2.3; % Reflector 2 coordinates as functions of the array Yr2=r_max/3; % & max depth dimensions Xt=L_array/2; Yt=0; % Source location (middle of array) r1=sqrt((Xr1-Xt)^2+(Yr1-Yt)^2); r2=sqrt((Xr2-Xt)^2+(Yr2-Yt)^2); td1=zeros(1,N); td2=td1; p_rfl=zeros(length(t),N); t_ind1=td1; t_ind2=td2; for i=1:N td1(i)=(r1+sqrt((X(i)-Xr1)^2+Yr1^2))/c; t_ind1(i)=round(td1(i)/dt); td2(i)=(r2+sqrt((X(i)-Xr2)^2+Yr2^2))/c; t_ind2(i)=round(td2(i)/dt); p_rfl(:,i)=(0.1/r1)*gauspuls(t-td1(i),fc,bw)+... (0.1/r2)*gauspuls(t-td2(i),fc,bw); % Includes spherical spreading end p_rfl_ht=hilbert(p_rfl); save 'Time_Series' % This figure can show the time-series of various % figure; plot(t*1e6,p_rfl(:,1),'k',t*1e6,p_rfl(:,16),'b--',... % t*1e6,p_rfl(:,25),'r-.');grid % xlabel('Time, (\mus)'); ylabel('Signal') % ------------------------------------------------------------ % Plot envelope as a function of time for all receive elements (like a % waterfall plot) figure; imagesc(t*1e6,X*1e3,abs(p_rfl_ht')) xlabel('Time, (\mus)'); ylabel('Element Location, (mm)')