matlab 产生高斯随机粗糙面的函数 输入变量为点数 长度 相关长度 均方根高度.rar

function [f,df,ddf,x]=rsgeng(N,rL,h,lc,seed); %RSGENG generates 1D Gaussian random rough surfaces with Gaussian Spectrum. % % [f,df,x]=rsgeng(N,rL,h,lc,seed) % % INPUT: % % N=total number of sample points % rL=rough surface length % h=rms height % lc=correlation length % seed=seed of random number generator % % OUTPUT: % % f=rough surface profile % df=df/dx % x=sample points on the surface % % -- Part of the Electromagnetic Wave MATLAB Library (EWML) -- % <http://www.emwave.com/> % Original: L. Tsang, 1998. randn('seed',seed); y=randn(N,1); for n=1:(N/2-1); bh(n)=(y(2*n-1)+i*y(2*n))/sqrt(2); end; bhc=conj(bh); bhf=fliplr(bhc); bi=[bh y(N-1) bhf y(N)]; kx=2*pi*[-N/2+1:1:N/2]/rL; y1=sqrt(wk(kx,h,lc)); y=y1*sqrt(2*pi*rL); b=y.*bi; xs=[b(N/2+1:1:N) b(1:1:N/2)]; xt=[xs(N),xs(1:1:N-1)]; ft=ifft(xt,N); ft=ft*N/rL; fs=[ft(2:1:N),ft(1)]; f=[fs(N/2+1:1:N) fs(1:1:N/2)]; f=real(f); dx=rL/N; x=[-N/2+1:1:N/2]*dx; n=2:N-1; df1=(f(n+1)-f(n-1))/(2*dx); df=[(f(2)-f(N))/(2*dx),df1,(f(1)-f(N-1))/(2*dx)]; ddf1=(df(n+1)-df(n-1))/(2*dx); ddf=[(df(2)-df(N))/(2*dx),ddf1,(df(1)-df(N-1))/(2*dx)]; %%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Gaussian spectral density % %%%%%%%%%%%%%%%%%%%%%%%%%%%%% function y=wk(kx,h,lc) y=h^2*lc*exp(-(kx*lc*0.5).^2)/(2*sqrt(pi));