fk_FK变换_fk变换理论_fk_

function [S,f,k] = fk(d,dt,dx,L); %FK: compute FK spectrum of a seismic gather. % % [S,f,k] = fk(d,dt,dx,L); % % IN d: data (traces in columns) % dt: time interval % dx: spatial increment between traces % L: apply spectral smoothing using a separable % 2D Hamming window of LxL samples % % OUT S: FK spectrum % f: freq axis in Hz % k: wave-number spectrum in cylces/m (if dx is in meters) % % Note: when plotting spectra (S) use log(S) or S.^alpha (alpha=0.1-0.3) to % increase the visibility of small events or background % % Example: % % [d,t,h] = linear_events; % [S,f,k] = fk(d,0.004,5,9); subplot(221);wigb(d,1,h,t); % xlabel('offset [m]'); ylabel('t [s]'); % subplot(222);imagesc(k,f,S); % xlabel('k [c/m]'); ylabel('f [Hz]'); % % Author(s): M.D.Sacchi (sacchi@phys.ualberta.ca) % Copyright 1988-2005 SeismicLab % Revision: 1.2 Date: Ago/2005 % % Signal Analysis and Imaging Group (SAIG) % Department of Physics, UofA % [nt,nx]=size(d); nk = 4*(2^nextpow2(nx)); nf = 4*(2^nextpow2(nt)); S = fftshift( abs(fft2(d,nf,nk)) ); H = hamming(L)*hamming(L)'; S = conv2(S,H,'same'); S = S(nf/2:nf,:); f = (0:1:nf/2)/nf/dt; k = (-nk/2+1:1:nk/2)/nk/dx;