matlab 双线性插值简单实现代码

clear
clc
close
X=linspace(-pi,pi,10);
Y=linspace(-2pi,2pi,10);
[xx,yy]=meshgrid(X,Y);
zz=1+sin(2xx)+sin(2yy);
[r,c]=size(zz);

fig=figure();
set(fig,‘color’,‘white’)
set(gca,‘FontSize’,18)
xlabel(‘x’)
ylabel(‘y’)
zlabel(‘z’)
hold on
grid on

for idx=1:r
for jdx=1:c
plot3(xx(idx,jdx),yy(idx,jdx),zz(idx,jdx),‘b*’,‘MarkerSize’,10)
end
end

xstar=-2;
ystar=1.5;
locx=find(xstar<X,1);
locy=find(ystar<Y,1);

x0=X(locx-1);
x1=X(locx);
y0=X(locy-1);
y1=X(locy);

z00=zz(locx-1,locy-1);
z10=zz(locx,locy-1);
z01=zz(locx-1,locy);
z11=zz(locx,locy);

plot3(x0,y0,z00,‘gs’,‘MarkerSize’,10)
plot3(x1,y0,z10,‘gs’,‘MarkerSize’,10)
plot3(x0,y1,z01,‘gs’,‘MarkerSize’,10)
plot3(x1,y1,z11,‘gs’,‘MarkerSize’,10)

zU=z01+(z11-z01)/(x1-x0)(xstar-x0);
zL=z00+(z10-z00)/(x1-x0)(xstar-x0);

plot3(xstar,y0,zL,‘r*’,‘MarkerSize’,10)
plot3(xstar,y1,zU,‘r*’,‘Markersize’,10)

zstar=zL+(zU-zL)/(y1-y0)*(ystar-y0);
plot3(xstar,ystar,zstar,‘k’,‘MarkerSize’,10)