clc
clear?all;%?clear?all?variables?from?previous?sessions
close?all;

covername?=?input（‘Enter?image?file?name?with?extension:?‘?‘s‘）;
messagename?=?input（‘Enter?message?image?file?name?with?extension:?‘?‘s‘）;

cover?=?imread（covername）;

sz?=?size（cover）;
rows?=?sz（11）;???????????????
cols?=?sz（12）;
colors?=?max（max（cover））;??

%r=1;
%for?i=1:rows
%????for?j=1:3:cols
%????????rgb（r1）=cover（ij）;
%????????rgb（r2）=cover（ij+1）;
%????????rgb（r3）=cover（ij+2）;
%????????r=r+1;
%????end
%end



%gray=rgb2gray（rgb）;
%cover=gray;

fd?=?fopen?（messagename?‘r‘）;
message?=?fgetl（fd）;
messagelength?=?length（message）;

figure（1）?imshow（cover）;?title（‘Original?Image?（Cover?Image）‘）;
%disp（message）;

%cover=double（cover）;
%message=double（message）;
message?=?uint8（message）;

coverzero?=?cover;
%disp（coverzero）;

%coverzero=imread（‘GrayScale.bmp‘）;

quant_multiple?=?1;????
???????????????????????
blocksize?=?8;?????????
DCT_quantizer?=?...????
	[?16??11??10??16??24??40??51??61;?...
	??12??12??14??19??26??58??60??55;?...
	??14??13??16??24??40??57??69??56;?...
	??14??17??22??29??51??87??80??62;?...
	??18??22??37??56??68?109?103??77;?...
	??24??35??55??64??81?104?113??92;?...
	??49??64??78??87?103?121?120?101;?...
	??72??92??95??98?112?100?103??99?];



%figure（1）
%image（coverzero）
figure（2）;imshow（coverzero）;
%colormap（map）
title（‘Original?image‘）;
%figure（2）


%coverzero?=?coverzero?-?ceil（colors/2）;

%figure（2）;imshow（coverzero）;

pad_cols?=?（1?-?（cols/blocksize?-?floor（cols/blocksize）））?*?blocksize;
if?pad_cols?==?blocksize?pad_cols?=?0;?end
pad_rows?=?（1?-?（rows/blocksize?-?floor（rows/blocksize）））?*?blocksize;
if?pad_rows?==?blocksize?pad_rows?=?0;?end

for?extra_cols?=?1:pad_cols
??coverzero（1:rows?cols+extra_cols）?=?coverzero（1:rows?cols）;
end

cols?=?cols?+?pad_cols;????%?coverzero?is?now?pad_cols?wider

for?extra_rows?=?1:pad_rows
??coverzero（rows+extra_rows?1:cols）?=?coverzero（rows?1:cols）;
end

rows?=?rows?+?pad_rows;????%?coverzero?is?now?pad_rows?taller


for?row?=?1:?blocksize:?rows
??for?col?=?1:?blocksize:?cols
??????
??????DCT_matrix?=?coverzero（row:?row?+?blocksize-1?col:?col?+?blocksize-1）;
??????DCT_matrix?=?DCT2（DCT_matrix）;

???????%?quantize?it?（levels?stored?in?DCT_quantizer?matrix）:
????%DCT_matrix?=?floor?（DCT_matrix?...
????%??????./?（DCT_quantizer（1:blocksize?1:blocksize）?*?quant_multiple）?+?0.5）;
????DCT_matrix?=?round（DCT_matrix?...
??????????./?（DCT_quantizer（1:blocksize?1:blocksize）?*?quant_multiple））;
??????%DCT_matrix=round（DCT_matrix）;
???????%?place?it?into?the?compressed-image?matrix:
????jpeg_img（row:?row?+?blocksize-1?col:?col?+?blocksize-1）?=?DCT_matrix;
??end
end

figure（3）;hist（jpeg_img）;
figure（4）;imshow（jpeg_img）;

bitlength=1;
%messagebit=zeros（messagelength*8）;

for?i=1:messagelength
%imbed=7;

for?imbed=1:8
messageshift=bitshift（message（i）8-imbed）;

showmess=uint8（messageshift）;
s

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件??????10091??2003-07-31?08:05??lenna.JPG

?????文件?????786486??2010-05-19?22:51??pepper.bmp

?????文件???????7280??2014-09-26?09:34??Jsteg.m

?????文件?????263222??2010-05-19?22:45??lena512.bmp

-----------?---------??----------?-----??----

??????????????1067079????????????????????4