close all;clear all;clc;
J = imread('lena.jpg');
K = imadjust(J,[70/255 160/255],[]);
figure;
subplot(121),imshow(J);
subplot(122),imshow(K);
[m,n] = size(J);
mm = round(m/2);
mn = round(n/2);
[p,q] = size(K);
pp = round(p/2);
qq = round(q/2);
J = double(J);
K = double(K);
colorsum = 0.0;
Javg = mean2(J)  %求原图像一阶矩
Kavg = mean2(K)  %求增强对比度后的图像一阶矩
Jstd = std(std(J))  %求原图像的二阶矩，因为一次std函数表示按列求标准差，两次std表示求整个矩阵的标准差
Kstd = std(std(K))   %求增强对比度后的图像二阶矩
for i=1:mm
    for j=1:mn
        colorsum = colorsum+(J(i,j)-Javg)^3;
    end
end
Jske = (colorsum/(mm*mn))^(1/3)  %求原图像的三阶矩
colorsum = 0.0;
for i=1:pp
    for j=1:qq
        colorsum = colorsum + (J(i,j)-Kavg)^3;
    end
end
Kske = (colorsum/(pp*qq))^(1/3)  %求增强对比度后的图像三阶矩