这是得到干涉图的代码，怎样还原干涉物体表面的三维图呢？
xmax = 15;
ymax = 15;
Lambda = 632.8e-006;
f=200;
n=1.0;
N=150;
x=linspace(-xmax,xmax,N);
y=linspace(-ymax,ymax,N);
for i=1:N
for j= 1:N
r(i,j)=sqrt(x(i)*x(i)+y(j)*y(j));
if 30<=i&i<=120&30<=j&j<=120
d=0.39
else
d=0.39005
end B(i,j)=cos(pi*(2*n*d*cos(asin(n*sin(atan(r(i,j)/f)))))/Lambda).^2;
end
end
figure(gcf);
NClevels=200;
Br=2.5*B*NClevels;
image(x,y,Br);
colormap(gray(NClevels));