囊肿模型.rar_buildd2l_cyst_phant_pooriru

% Example of use of the new Field II program running under % Matlab. % % This example shows how a linear array B-mode system scans an image % % This script assumes that the field_init procedure has been called % Here the field simulation is performed and the data is stored % in rf-files; one for each rf-line done. The data must then % subsequently be processed to yield the image. The data for the % scatteres are read from the file pht_data.mat, so that the procedure % can be started again or run for a number of workstations. % % Example by Joergen Arendt Jensen and Peter Munk, % Version 1.2, August 14, 1998, JAJ. % Ver. 1.1: 1/4-98: Procedure xdc_focus_center inserted to use the new % focusing scheme for the Field II program % Ver. 2.0: 13/8 2007: Parallel version that checks whether the simulation % of a line has been made before, which makes it possible % to run the code in parallel on multiple workstations. % Generate the transducer apertures for send and receive f0=3.5e6; % Transducer center frequency [Hz] fs=100e6; % Sampling frequency [Hz] c=1540; % Speed of sound [m/s] lambda=c/f0; % Wavelength [m] width=lambda; % Width of element element_height=5/1000; % Height of element [m] kerf=0.05/1000; % Kerf [m] focus=[0 0 70]/1000; % Fixed focal point [m] N_elements=192; % Number of physical elements N_active=64; % Number of active elements % Set the sampling frequency set_sampling(fs); % Generate aperture for emission xmit_aperture = xdc_linear_array (N_elements, width, element_height, kerf, 1, 10,focus); % Set the impulse response and excitation of the xmit aperture impulse_response=sin(2*pi*f0*(0:1/fs:2/f0)); impulse_response=impulse_response.*hanning(max(size(impulse_response)))'; xdc_impulse (xmit_aperture, impulse_response); excitation=sin(2*pi*f0*(0:1/fs:2/f0)); xdc_excitation (xmit_aperture, excitation); % Generate aperture for reception receive_aperture = xdc_linear_array (N_elements, width, element_height, kerf, 1, 10,focus); % Set the impulse response for the receive aperture xdc_impulse (receive_aperture, impulse_response); % Load the computer phantom if ~exist('pht_data.mat') disp('Scatterer positions should be made by the script mk_pht') disp('before this script can be run') return else load pht_data end % Set the different focal zones for reception focal_zones=[30:20:200]'/1000; Nf=max(size(focal_zones)); focus_times=(focal_zones-10/1000)/1540; z_focus=60/1000; % Transmit focus % Set the apodization apo=hanning(N_active)'; % Do linear array imaging no_lines=50; % Number of lines in image image_width=40/1000; % Size of image sector d_x=image_width/no_lines; % Increment for image % Do imaging line by line for i=[1:no_lines] % Test if the file for the line exist. % Skip the simulation, if the line exits and % go the next line. Else make the simulation file_name=['rf_data/rf_ln',num2str(i),'.mat']; if ~exist(file_name) % Save a file to reserve the calculation cmd=['save rf_data/rf_ln',num2str(i),'.mat i']; eval(cmd); disp(['Now making line ',num2str(i)]) % The the imaging direction x= -image_width/2 +(i-1)*d_x; % Set the focus for this direction with the proper reference point xdc_center_focus (xmit_aperture, [x 0 0]); xdc_focus (xmit_aperture, 0, [x 0 z_focus]); xdc_center_focus (receive_aperture, [x 0 0]); xdc_focus (receive_aperture, focus_times, [x*ones(Nf,1), zeros(Nf,1), focal_zones]); % Calculate the apodization N_pre = round(x/(width+kerf) + N_elements/2 - N_active/2); N_post = N_elements - N_pre - N_active; apo_vector=[zeros(1,N_pre) apo zeros(1,N_post)]; xdc_apodization (xmit_aperture, 0, apo_vector); xdc_apodization (receive_aperture, 0, apo_vector); % Calculate the received response [rf_data, tstart]=calc_scat(xmit_aperture, receive_aperture, phantom_positions, phantom_amplitudes); % Store the result cmd=['save rf_data/rf_ln',num2str(i),'.mat rf_data tstart']; disp(cmd) eval(cmd); else disp(['Line ',num2str(i),' is being made by another machine.']) end end % Free space for apertures xdc_free (xmit_aperture) xdc_free (receive_aperture) disp('You should now run make_image to display the image')