clc;
close?all;
clear;

%%%%%%%%%%%%%%%%%%%%%%%?Reading?a?Secret?Text?File?%%%%%%%%%%%%%%%%%%%%%%%%
file_id?=?fopen（‘message.txt‘‘r‘）;
file_content?=?fread（file_id）;
file_length?=?length（file_content）;
in?=?[];
in?=?[in?dec2bin（file_length20）];?%character?to?binary?conversion?
for?i=1:file_length?????????????????????????????????????????
????in=[in?dec2bin（file_content（i）7）];
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%?Reading?Cover?Image?%%%%%%%%%%%%%%%%%%%%%%%%%%%
cover_image?=?imread（‘cover_image.bmp‘）;?%get?cover?image????????????????????????????????????????
red?=?cover_image（::1）;?%seperating?rgb?values?
blue?=?cover_image（::2）;
green?=?cover_image（::3）;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%?embedding?Data?%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
color?=?red;?%red?color?selected?for?embedding
[rc]?=?size（color）;
final?=?double（color）;?
next=0;
capacity=0;?%total?no?of?bits?that?can?be?embedded

for?x=0:1:r-1?
????for?y=0:2:c-1
????????enable?=?1;?%enable=0?when?new?pixels?may?fall?off?the?boundary
????????p?=?color（1+x1+y:2+y）;?%block?of?two?pixels?pi?&?pi+1
????????p?=?double（p）;
????????d?=?p（12）?-?p（11）;?%d?=?difference?between?2?pixel
????????d_abs?=?abs（d）;?%absolute?difference
????????lb=[0?8?16?32?64?128];?%lowerbound
????????ub=[7?15?31?63?127?255];?%upperbound
????????for?i=1:1:6?%test?the?R?boundary
????????????if（（d_abs?>=?lb（i））?&&?（d_abs?<=?ub（i）））?%selecting?range
????????????????%check?if?any?pixel?in?a?block?fall?off?the?boundary?[0255]
????????????????even2?=?mod（d2）;?
????????????????m2?=?ub（i）?-?d;
????????????????if?（even2?==?0）
????????????????????Pcheck=[p（11）-floor（m2/2）?p（12）+ceil（m2/2）];
????????????????else
????????????????????Pcheck=[p（11）-ceil（m2/2）?p（12）+floor（m2/2）];
????????????????end
????????????????if（Pcheck（1）<0?||?Pcheck（2）<0?||?Pcheck（1）>255?||?Pcheck（2）>255）
????????????????????enable?=?0;
????????????????????break
????????????????end
????????????????
????????????????n?=?ub（i）-lb（i）+1;?%quantization?width?of?range
????????????????t?=?floor（log2（n））;?%maximum?bit?can?be?embedded?in?2?pixels
????????????????capacity=capacity+t;?%max?capacity?of?the?cover?image?
????????????????
????????????????%check?if?next?exceeds?the?length?of?message
????????????????if（next>length（in））?
????????????????????m=0;
????????????????%check?if?next+t?exceeds?the?length?of?message
????????????????elseif（next+t>length（in））?
????????????????????if（1+next>=length（in））
????????????????????????k=zeros（1t）;
????????????????????else
????????????????????????k=in（1+next:length（in））;
????????????????????end
????????????????????diff?=next+t-length（in）;
????????????????????k1=zeros（1t）;
????????????????????if（diff>0）
????????????????????????for?j=1:next+t-length（in）
????????????????????????????k1（j）=k（j）;
????????????????????

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

?????文件?????786486??2012-05-12?18:09??Image_Steg\cover_image.bmp

?????文件??????12342??2012-05-09?23:43??Image_Steg\cover_image2.bmp

?????文件???????4951??2012-05-27?16:40??Image_Steg\data_embedding.m

?????文件???????2743??2012-05-27?21:24??Image_Steg\data_extraction.m

?????文件???????2735??2012-05-27?01:27??Image_Steg\histogram_analysis.m

?????文件???????4757??2012-05-27?18:15??Image_Steg\message.txt

?????文件????????923??2012-05-27?16:31??Image_Steg\psnr.m

?????文件????????897??2012-05-27?18:13??Image_Steg\Read?Me?Please!.txt

?????目錄??????????0??2012-10-10?13:30??Image_Steg

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

???????????????815834????????????????????9