psf_example.tar.gz_Field_II仿真_PSF 成像_field-ii_散射成像_点散射

% Make differene images for showing the effect of % focusing and apodization % % This script assumes that the field_init procedure has been called % % Example by Joergen Arendt Jensen, March 25, 1997. % constant F# added by Peter Munk, April 8, 1997 % Version 1.2, August 13, 2007, JAJ: Printout changed % % Generate the transducer apertures for send and receive f0=3e6; % 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=0.1/1000; % Kerf [m] focus=[0 0 70]/1000; % Fixed focal point [m] N_elements=128; % Number of physical elements N_active=64; % Number of active elements xmit_N_active=128; % Number of active transmit elements for constant F# rec_N_active=128; % Number of active receive elements for constant F# % Set the sampling frequency set_sampling(fs); % Generate aperture for emission emit_aperture = xdc_linear_array (N_elements, width, element_height, kerf, 1, 1,focus); % Set the impulse response and excitation of the emit aperture impulse_response=sin(2*pi*f0*(0:1/fs:2/f0)); impulse_response=impulse_response.*hanning(max(size(impulse_response)))'; xdc_impulse (emit_aperture, impulse_response); excitation=sin(2*pi*f0*(0:1/fs:2/f0)); xdc_excitation (emit_aperture, excitation); % Generate aperture for reception receive_aperture = xdc_linear_array (N_elements, width, element_height, kerf, 1, 1,focus); % Set the impulse response for the receive aperture xdc_impulse (receive_aperture, impulse_response); % Load the computer phantom [phantom_positions, phantom_amplitudes] = pts_pha; % Do linear array imaging no_lines=20; % Number of lines in image image_width=20/1000; % Size of image sector d_x=image_width/no_lines; % Increment for image % Make the different simulations % Single focus for emission and reception, no apodization figure(1) disp('Making images without apodization (figure 1)') subplot(161) disp('Single transmit and receive focus') sesr mk_img title('A') axis on ylabel('Axial distance [mm]') text(40,135,'Lateral distance [mm]') % Introduce a number of receive focus zones subplot(162) disp('Single transmit and multiple receive foci') semr mk_img title('B') % Multiple focusing in both transmit and receive subplot(163) disp('Multiple transmit and multiple receive foci') memr mk_img title('C') xlabel('Lateral distance [mm]') % Use 128 elements instead subplot(164) disp('Multiple transmit and multiple receive foci (128 elements)') memr128 mk_img title('D') % Use 128 elements with continous receive focus subplot(165) disp('Multiple transmit and continuous receive foci (128 elements)') mecr128 mk_img title('E') % Use 128 elements instead with no apodization % constant F# rec=2 and xmit=4 subplot(166) disp('Constant F# number focusing') fnumna mk_img title('F') % Perform the simulations again using apodization % Single focus for emission and reception with apodization figure(2) disp('Making images with apodization (figure 2)') subplot(161) disp('Single transmit and receive focus') sesra mk_img axis on title('A') ylabel('Axial distance [mm]') text(40,135,'Lateral distance [mm]') % Introduce a number of receive focus zones with apodization subplot(162) disp('Single transmit and multiple receive foci') semra mk_img title('B') % Multiple focusing in both transmit and receive with apodization subplot(163) disp('Multiple transmit and multiple receive foci') memra mk_img title('C') xlabel('Lateral distance [mm]') % Use 128 elements instead with apodization subplot(164) disp('Multiple transmit and multiple receive foci (128 elements)') memr128a mk_img title('D') % Use 128 elements with 2 mm between receive focuses subplot(165) disp('Multiple transmit and continuous receive foci (128 elements)') mecr128a mk_img title('E') % Use 128 elements instead with apodization % constant F# rec=2 and xmit=4 subplot(166) disp('Constant F# number focusing') fnumwa mk_img title('F')