EMD算法原理:
![](https://img.laitimes.com/img/_0nNw4CM6IyYiwiM6ICdiwiIwczX0xiRGZkRGZ0Xy9GbvNGL2EzXlpXazxSP9ElTzklaOhXV65ke4wmYwhGWhxGZzwEMW1mY1RzRapnTtxkb5ckYplTeMZTTINGMShUYfRHelRHLwEzX39GZhh2css2RkBnVHFmb1clWvB3MaVnRtp1XlBXe0xyayFWbyVGdhd3LcV2Zh1Wa9M3clN2byBXLzN3btg3Pn5GcuITN1ADNzATM3IDNwkTMwIzLc52YucWbp5GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.png)
MATLAB代碼如下:
clear;
clc;
pout=imread('pout.tif');
[m,n]= size(pout);%讀取出圖檔的列像素個數和行像素個數
S = floor(rand(1,(m*n)/2)*5);%産生一組二分之一像素個數的0—4的随機數,作為待隐藏的資訊
carrier = reshape(pout,1,m*n);%将載體圖檔轉化為一維數組
figure(1);
subplot(1,2,1),imshow(pout), title('原始圖像');%顯示原始圖像;
%加密算法
for i=1:2:m*n
g1=double(carrier(i));
g2=double(carrier(i+1));
f=mod((g1+g2*2),5);
r=mod((S((i+1)/2)-f),5);
if(r==0) %r=0時,g1,g2保持不變
g1=g1;
g2=g2;
elseif(r<=2) %r小于等于二時,gr+1
if(r==1)
g1=g1+1;
else
g2=g2+1;
end
elseif(r>2) %r大于2時,g(5-r)—-5
if(5-r==1)
g1=g1-1;
else
g2=g2-1;
end
end
newcarrier(i)=uint8(g1);
newcarrier(i+1)=uint8(g2);
end
newimg=reshape(newcarrier,m,n);
subplot(1,2,2),imshow(newimg),title('嵌入資訊後');%列印嵌入資訊後的圖檔
%提取算法
for k=1:2:m*n
b1=double(newcarrier(k));
b2=double(newcarrier(k+1));
information((k+1)/2)=mod((b1+b2*2),5);
end
執行效果:
圖像的像素發生了變化:
提取資訊結果:
實驗中踩的坑:
圖像中均采用uint8的類型,f函數運算溢出的話,模将為0。是以在運算f之前,需要把g1,g2變量轉換為其他類型。到顯示新圖像之前還要将其轉換為uint8類型。