euclide.m

进行ISAR运动补偿的程序 kylsdone 方法来消除越距离单元走动,注释完整

function [s,V] = euclide(z,rho,theta)
% function EUCLIDE.M
% Nearest neighbor approximation algorithm
%
% Usage: [s,V] =  euclide(z,rho,theta)
% Where: z = M by N matrix with samples in frequency domain 
% rho, theta = radius and angles ofdata points
% interpolated niattix
% V = vector that includes [X0 dkx dky fl]

close all
% Variables bursts
bursts = size(z,1);
pul_burst = size(z,2);
rho = rho.*(4*pi/3e8);  %% frequency matrix in rad/mt
rhov = rho(1,:);
drho = rhov(2) - rhov(1);
ac = theta(bursts,1) - theta(1,pul_burst);

% Points of Interpolation
x = linspace(min(rhov), max(rhov)*cos(ac/2),pul_burst);
y = min(rhov)*tan(ac/2)*linspace(-1,1,bursts);
[fxi,fyi] = meshgrid(x,y);
fxd = rho.*cos(theta);
fyd = rho.*sin(theta);
dkx = fxi(1,2) - fxi(1,1);
dky = fyi(2,1) - fyi(1,1);
X0 = pi/(rhov(2) - rhov(1));

% Interpolation
flops(0)
s = zeros(size(z));
for a = 1:bursts,a
   for b = 1:pul_burst,
      rr = sqrt(fxi(a,b)^2 + fyi(a,b)^2);
      tt = atan2(fyi(a,b),fxi(a,b));
      n = 1 + fix((rr - min(rhov))/drho);
      c = rr - (min(rhov) + drho*(n-1));
      t2 = (theta(:,n+1) - theta(:,n))*c/drho + theta(:,n);
      if a==128
         tt=tt-0.001;
      end
      k = min(find(tt<t2)) - 1;
      vx = [fxd(k,n) fxd(k+1,n) fxd(k+1,n+1) fxd(k,n+1)];
      vy = [fyd(k,n) fyd(k+1,n) fyd(k+1,n+1) fyd(k,n+1)];
      d = sqrt((fxi(a,b)-vx).^2 + (fyi(a,b)-vy).^2);
      s(a,b)=z(k,n)/d(1)+z(k+1,n)/d(2)+z(k+1,n+1)/d(3)+z(k,n+1)/d(4);
      s(a,b)=s(a,b)/sum(1./d);
end; end
fl = flops;

V = [X0 dkx dky fl];