M=256;??%原圖256x256
N=32;	%水印32x32同時256/8=32
K=8;????%原圖按8x8分塊
I=zeros（MM）;
EI=zeros（MM）;			%保存原圖的邊界圖
J=zeros（NN）;
BLOCK=zeros（KK）;
Alpha1=0.1;
Alpha2=0.03;
T1=3;

subplot（321）;
I=imread（‘original.bmp‘）;
imshow（I）;
title（‘原圖‘）;

EI=edge（I‘prewitt‘）;
subplot（322）;
imshow（EI）;
title（‘原圖邊界‘）;

subplot（323）;
J=imread（‘originalWater.bmp‘）;
imshow（J）;
title（‘水印‘）;

%%%%%%%??分塊DCT變換	%%%%%%%
for?p=1:N				%256/8
????for?q=1:N
????????x=（p-1）*K+1;	%每個小塊左上角的點
????????y=（q-1）*K+1;
????????BLOCK=I（x:x+K-1y:y+K-1）;		%取每個小塊相應元素保存到BLOCK
????????BLOCK=dct2（BLOCK）;				%二維離散余弦變換
		EIBlock=EI（x:x+K-1?y:y+K-1）;
????????%%		嵌入水印反DCT變換
????????T=sum（sum（EIBlock））;
		if?T>T1
			Alpha=Alpha1;
		else
			Alpha=Alpha2;
????????end
????????if?J（pq）==0
????????????a=-1;
????????else
????????????a=1;
????????end
????????BLOCK=BLOCK*（1+a*Alpha）;
????????BLOCK=idct2（BLOCK）;		%反二維離散余弦變換
????????I（x:x+K-1y:y+K-1）=BLOCK;
????end
end

subplot（324）;
imshow（I）;
title（‘嵌入水印后的圖像‘）;
imwrite（I‘marked.bmp‘）;


%%%%%??提取水印??%%%%%
I=imread（‘original.bmp‘）;		%原圖
P=imread（‘marked.bmp‘）;	%嵌入水印的圖像
%提取水印算法
for?p=1:N
????for?q=1:N
????????x=（p-1）*K+1;
????????y=（q-1）*K+1;
????????BLOCK1=I（x:x+K-1y:y+K-1）;
????????BLOCK1=idct2（BLOCK1）;
????????BLOCK2=P（x:x+K-1y:y+K-1）;
????????BLOCK2=idct2（BLOCK2）;
????????a=BLOCK2（11）/BLOCK1（11）-1;
????????if?a<0
			W（pq）=0;
????????else
????????????W（pq）=1;
????????end
????end
end

subplot（325）;
imshow（W）;
title（‘提取的水印‘）;
imwrite（W‘waterPrint2.bmp‘）;

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件???????66614??2018-06-20?17:59??original.bmp
?????文件?????????190??2018-06-20?17:47??originalWater.bmp
?????文件????????1676??2018-06-20?18:03??self_adopt_dct.m