% % Cylindrical Focused Array Transducer Example 1. % % \$Revision: 565 \$ \$Date: 2009-09-17 22:24:06 +0200 (Thu, 17 Sep 2009) \$ \$LastChangedBy: dream \$ Fs = 10; % Sampling freq. in MHz. Ts = 1/Fs; % % Observation point(s). % z = 50; % [mm] % 1 - one point, 0 - 50 points along x-axis. if 1 % One point. xo = 0; yo = 0; zo = z; ro = [xo yo zo]; Ro = ro; disp(['Observation point (x,y,z) = ' num2str(Ro)]) else % Points along x-axis. d = 1; % [mm] xo = (0:d:50); % 0-50 mm. yo = zeros(length(xo),1); zo = z*ones(length(xo),1); Ro = [xo(:) yo(:) zo(:)]; end % Descretization parameters. dx = 0.01; % [mm]. dy = 0.01; % [mm] dt = Ts; % [us]. nt = 500; % Length of spatial impulse response vector. s_par = [dx dy dt nt]; % Material parameters. v = 1.0; % Normal velocity. cp = 1000; % Sound speed [m/s]. alfa = 0; % Absorbtion [dB/(cm MHz)]. m_par = [v cp alfa]; % Delay. t_z = z*1e3/cp; %delay = 0; % Start at 0 [us]. delay = t_z; % Start at t_z [us]. % Element size [mm]. a = 1; % x-size. b = 20; % y-size. R = 100; % Curvature radius. geom_par = [a b R]; % Grid function (position vectors of the elements). x = -10:1:10; [gx,gy] = meshgrid(x); gx = gx(:); gy = zeros(length(gx),1); gz = zeros(length(gx),1); G = [gx gy gz]; % % Focusing parameters. % %foc_met = 'off'; %foc_met = 'x'; %foc_met = 'y'; foc_met = 'xy'; %foc_met = 'x+y'; focal = 50; % Focus radius [mm]. % User defined focusing. %foc_met = 'ud'; % % Focusing vector for 'ud'. Delays in [us]. %focal = zeros(length(gx),1); % unfocused. % Beam steering. steer_met = 'off'; %steer_met = 'x'; %steer_met = 'y'; %steer_met = 'xy'; theta = 0; % Angle in x-direction. phi = 0; % Angle in y-direction. steer_par = [theta phi]; % Apodization. apod_met = 'off'; %apod_met = 'ud'; % User defined. %apod_met = 'triangle'; %apod_met = 'gauss'; %apod_met = 'raised'; % Raised cosine. %apod_met = 'simply'; % Simply supported. %apod_met = 'clamped'; apod = ones(length(gx),1); % Apodization weights for 'ud'. win_par = 1; % Parameter for raised cos and Gaussian apodization functions. H = dream_arr_cylind_f(Ro,geom_par,G,s_par,delay,m_par,... foc_met,focal,steer_met,steer_par,apod_met,apod,win_par,'stop'); figure(1) clf t = 0:Ts:Ts*(nt-1); if size(H,2)>1 mesh(xo,t+delay,H); xlabel('x [mm]') ylabel('t [\mus]') axis tight view([135 32]) else plot(t+delay,H); axis tight ax = axis; %axis([0 50 ax(3) ax(4)]) xlabel('t [\mus]') grid end title(['SIR for a Linear Array Transducer with Cylindrical ' ... 'Elements'])