图像对比度计算

matlab中求解方式：

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %计算图像对比度 %方法一：中心像素灰度值与周围4近邻像素灰度值之差的平方之和，除以以上平方项的个数。 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% functioncg = duibidu4(f) %f为输入图像，cg为输出的对比度数值，是英文contrast gradient的首字母组合 [m,n] = size(f);%求原始图像的行数m和列数n g = padarray(f,[1 1],'symmetric','both');%对原始图像进行扩展，比如50*50的图像，扩展后变成52*52的图像， %扩展只是对原始图像的周边像素进行复制的方法进行 [r,c] = size(g);%求扩展后图像的行数r和列数c g = double(g);  %把扩展后图像转变成双精度浮点数 k = 0;  %定义一数值k，初始值为0 fori=2:r-1 forj=2:c-1 k = k+(g(i,j-1)-g(i,j))^2+(g(i-1,j)-g(i,j))^2+(g(i,j+1)-g(i,j))^2+(g(i+1,j)-g(i,j))^2; end end cg = k/(4*(m-2)*(n-2)+3*(2*(m-2)+2*(n-2))+4*2);%求原始图像对比度 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %计算图像对比度 %方法二：中心像素灰度值与周围8近邻像素灰度值之差的平方之和，除以以上之差的个数。 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% functioncg = duibidu8(f) %f为输入图像，cg为输出的对比度数值，是英文contrast gradient的首字母组合 [m,n] = size(f);%求原始图像的行数m和列数n g = padarray(f,[1 1],'symmetric','both');%对原始图像进行扩展，比如50*50的图像，扩展后变成52*52的图像， %扩展只是对原始图像的周边像素进行复制的方法进行 [r,c] = size(g);%求扩展后图像的行数r和列数c g = double(g);  %把扩展后图像转变成双精度浮点数 k=0;  %定义一数值k，初始值为0 fori=2:r-1 forj=2:c-1 k = k+(g(i,j-1)-g(i,j))^2+(g(i-1,j)-g(i,j))^2+(g(i,j+1)-g(i,j))^2+(g(i+1,j)-g(i,j))^2+... (g(i-1,j-1)-g(i,j))^2+(g(i-1,j+1)-g(i,j))^2+(g(i+1,j-1)-g(i,j))^2+(g(i+1,j+1)-g(i,j))^2; end end cg = k/(8*(m-2)*(n-2)+6*(2*(m-2)+2*(n-2))+4*3);%求原始图像对比度