clc;
i=imread（‘E:\Student\receive\flower.jpg‘）;
a=rgb2gray（i）;
%???subplot（133）;imshow（a）;?title（‘灰度圖‘）;
[linerow]=size（a）;
L=1;
R=1;
for?i=1:2:line;
????for?j=1:2:row;
????????b1（LR）=a（ij）;
????????R=R+1;
????end;
????L=L+1;
????R=1;
end;????????
c=（0.5）*a;c1=floor（c）;
?subplot（131）imshow（a）;?title（‘灰度‘）;
?subplot（132）;imshow（b1）;?title（‘4倍采樣圖‘）;
subplot（133）imshow（c）title（‘灰度級降為128級‘）;

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

?????文件????1772080??2016-06-28?11:17??08田林玉\08田林玉.docx

?????文件????????432??2016-06-28?10:50??08田林玉\m1.m

?????文件????????653??2016-06-28?10:47??08田林玉\m2.m

?????文件???????1655??2016-06-28?11:14??08田林玉\m3.m

?????文件???????1072??2016-06-28?09:39??08田林玉\m31.m

?????文件????????289??2016-06-28?09:58??08田林玉\m4.m

?????文件????????936??2016-06-28?10:10??08田林玉\m5.m

?????文件????????481??2016-06-28?10:21??08田林玉\m6.m

?????文件????????376??2016-06-28?10:13??08田林玉\m7.m

?????目錄??????????0??2016-07-02?23:42??08田林玉

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

??????????????1777974????????????????????10