图像像素灰度内插(Matlab实现)

时间：2023-01-01 07:07:15

常用的像素灰度内插法：最近邻元法、双线性内插法、三次内插法

%%像素灰度内插

factor = 0.75;%缩放比

u = 0.6;v = 0.7;

itp1 = uint8(zeros(ceil(h/factor),ceil(w/factor)));

itp2 = uint8(zeros(ceil(h/u),ceil(w/v)));

itp3 = uint8(zeros(ceil(h/u),ceil(w/v)));

下述的J3为待插值灰度图像，itp为插值图像

1.最近邻元法

在待求像素的四邻像素中，将距离这点最近的邻像素灰度赋给待求像素。

%最近邻元法

 for i = :h/factor

    for j = :w/factor

        itp1(i,j) = J3(floor(i*factor+0.5),floor(j*factor+0.5));

    end

 end

2.双线性内插法

图像像素灰度内插(Matlab实现)

图像像素灰度内插(Matlab实现)

%双线性内插法

for i = :h/u-

    for j = :w/v-

        itp2(i,j) = (-(i*u-floor(i*u)))*(-(j*v-floor(j*v)))*J3(floor(i*u),floor(j*v))...

                   +(-(i*u-floor(i*u)))*(j*v-floor(j*v))*J3(floor(i*u),floor(j*v)+)...

                   +(i*u-floor(i*u))*(-(j*v-floor(j*v)))*J3(floor(i*u)+,floor(j*v))...

                   +(i*u-floor(i*u))*(j*v-floor(j*v))*J3(floor(i*u)+,floor(j*v)+);         

    end

end

3.三次内插法

图像像素灰度内插(Matlab实现)

图像像素灰度内插(Matlab实现)

function [f] = S(x)
if (0<=abs(x))&&(abs(x)<1)
    f = 1-2*(abs(x))^2+(abs(x))^3;
elseif (1<=abs(x))&&(abs(x)<2)
    f = 4-8*abs(x)+5*(abs(x))^2-(abs(x))^3;
else
    f = 0;
end
end

%三次内插法

f = double(J3);

u = 0.6;v = 0.7;

for i = ceil(/u):h/u-

    for j = ceil(/v):w/v-

       A = [S(+(j*v-floor(j*v))) S((j*v-floor(j*v))) S(-(j*v-floor(j*v))) S(-(j*v-floor(j*v)))];

       C = [S(+(i*u-floor(i*u)));S((i*u-floor(i*u)));S(-(i*u-floor(i*u)));S(-(i*u-floor(i*u)))];

       i1 = floor(i*u); j1 = floor(j*v);

       B = [f(i1-,j1-) f(i1-,j1) f(i1-,j1+) f(i1-,j1+);

            f(i1,j1-) f(i1,j1) f(i1,j1+) f(i1,j1+);

            f(i1+,j1-) f(i1+,j1) f(i1+,j1+) f(i1+,j1+);

            f(i1+,j1-) f(i1+,j1) f(i1+,j1+) f(i1+,j1+);];

        itp3(i,j) = A*B*C;

    end

end

上述的内插法处理的结果出现了黑边，可以通过将黑边区域赋予原始图像的对应区域的像素灰度值。

可通过以下循环实现。

%去黑边
    [m,n] = size(J3);%原始图像的行列数

    for i = :floor(1/u)

        for j = :floor(n/v)

          itp(i,j) = J3(ceil(i*u),ceil(j*v));

          itp(floor(m/u),j) = J3(m,ceil(j*v));

        end

    end

    for j = :floor(1/v)

        for i = :floor(m/u)

           itp(i,j) = J3(ceil(i*u),ceil(j*v));

           itp(i,floor(n/v)) = J3(ceil(i*u),n);

        end

    end

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