bilinear_interpolation_zoom.m

MATLAB双线性插值法对图像进行放大和缩小

function Bilinear_Interpolation_Zoom
f1024 = imread('1024.jpg');
f256 = f1024(1:4:end,1:4:end);
[m,n] = size(f256);
X0 = 4;
x = X0-1;
ff1024 = zeros(m+x*(m-1),n+x*(n-1));
for i = 1:m
    for j = 1:n
        ff1024(i+x*(i-1),j+x*(j-1)) = f256(i,j);
    end;
end;
ff1024 = double(ff1024);
for i = 1:m+x*(m-1)
    for j = 1:n+x*(n-1)
        r = mod(j-1,X0);
        s = mod(i-1,X0); 
        if r~=0 & s==0 
           ff1024(i,j) = round((r*ff1024(i,j+(X0-r))+(X0-r)*ff1024(i,j-r))/X0); 
        end;
        if r==0 & s~=0
           ff1024(i,j)=round((s*ff1024(i+(X0-s),j)+(X0-s)*ff1024(i-s,j))/X0);
        end;
        if r~=0 &s~=0 
            ff1024(i,j)=round((s*(r*ff1024(i-s,j+(X0-r))+(X0-r)*ff1024(i-s,j-r))/X0+(X0-s)*(r*ff1024(i+(X0-s),j+(X0-r))+(X0-r)*ff1024(i+(X0-s),j-r))/X0)/X0);
        end;
    end;
end;
ff1024 = uint8(ff1024);
figure('Name','The 256 x 256 picture','NumberTitle','off');imshow(f256);        
figure('Name','The 1024 x 1024 picture','NumberTitle','off');imshow(ff1024);