%一個修改后的PCA進行人臉識別的Matlab代碼

%?calc?xmeansigma?and?its?eigen?decomposition
allsamples=[];%所有訓練圖像
for?i=1:40
????for?j=1:5
??????a=imread（strcat（‘ORL\s‘num2str（i）‘\‘num2str（j）‘.pgm‘））;
??????%?imshow（a）;
??????b=a（1:112*92）;?%?b是行矢量?1×N，其中N＝10304，提取順序是先列后行，即從上到下，從左到右
??????b=double（b）;
??????allsamples=[allsamples;?b];??%?allsamples?是一個M?*?N?矩陣，allsamples?中每一行數據代表一張圖片，其中M＝200
??end
end
samplemean=mean（allsamples）;?%?平均圖片，1?×?N
for?i=1:200?xmean（i:）=allsamples（i:）-samplemean;?%?xmean是一個M?×?N矩陣，xmean每一行保存的數據是“每個圖片數據-平均圖片”
end;

sigma=xmean*xmean‘;???%?M?*?M?階矩陣
[v?d]=eig（sigma）;
d1=diag（d）;
[d2?index]=sort（d1）;?%以升序排序
cols=size（v2）;%?特征向量矩陣的列數
for?i=1:cols
????vsort（:i）?=?v（:?index（cols-i+1）?）;?%?vsort?是一個M*col（注:col一般等于M）階矩陣，保存的是按降序排列的特征向量每一列構成一個特征向量
????dsort（i）???=?d1（?index（cols-i+1）?）;??%?dsort?保存的是按降序排列的特征值，是一維行向量
end??%完成降序排列
%以下選擇90%的能量
dsum?=?sum（dsort）;
????dsum_extract?=?0;
????p?=?0;
????while（?dsum_extract/dsum?????????p?=?p?+?1;
????????dsum_extract?=?sum（dsort（1:p））;
????end
i=1;
%?（訓練階段）計算特征臉形成的坐標系
while?（i<=p?&&?dsort（i）>0）
????base（:i）?=?dsort（i）^（-1/2）?*?xmean‘?*?vsort（:i）;???%?base是N×p階矩陣，除以dsort（i）^（1/2）是對人臉圖像的標準化，詳見《基于PCA的人臉識別算法研究》p31
????i?=?i?+?1;
end

%?add?by?wolfsky?就是下面兩行代碼，將訓練樣本對坐標系上進行投影得到一個?M*p?階矩陣allcoor
allcoor?=?allsamples?*?base;
accu?=?0;

%?測試過程
for?i=1:40
????for?j=6:10?%讀入40?x?5?副測試圖像
????????a=imread（strcat（‘ORL\s‘num2str（i）‘\‘num2str（j）‘.pgm‘））;
????????b=a（1:10304）;
????????b=double（b）;
????????tcoor=?b?*?base;?%計算坐標，是1×p階矩陣
????????for?k=1:200?
????????????????mdist（k）=norm（tcoor-allcoor（k:））;
????????????end;
????????%三階近鄰?
?[distindex2]=sort（mdist）;
????????class1=floor（?index2（1）/5?）+1;
????????class2=floor（index2（2）/5）+1;
????????class3=floor（index2（3）/5）+1;
????????if?class1~=class2?&&?class2~=class3
????????????class=class1;
????????elseif?class1==class2
????????????class=class1;
????????????%elseif?class2==class3
??????????%??class=class2;
????????end;
????????if?class==i
????????????accu=accu+1;
????????end;
????end;
end;
accuracy=accu/200?%輸出識別率
zuobiao=[1:100];
plot（zuobiaoaccuracy）;

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

?????文件???????1579??1995-02-24?02:13??orl\README

?????文件??????10318??1994-04-18?21:17??orl\s1\1.pgm

?????文件??????10318??1994-04-18?21:07??orl\s1\10.pgm

?????文件??????10318??1994-04-18?21:17??orl\s1\2.pgm

?????文件??????10318??1994-04-18?21:17??orl\s1\3.pgm

?????文件??????10318??1994-04-18?21:17??orl\s1\4.pgm

?????文件??????10318??1994-04-18?21:17??orl\s1\5.pgm

?????文件??????10318??1994-04-18?21:07??orl\s1\6.pgm

?????文件??????10318??1994-04-18?21:07??orl\s1\7.pgm

?????文件??????10318??1994-04-18?21:07??orl\s1\8.pgm

?????文件??????10318??1994-04-18?21:07??orl\s1\9.pgm

?????文件??????10318??2008-06-18?17:33??orl\s1\1.pgmhex.TXT

?????文件?????209256??2008-07-05?11:13??orl\s1\pgm.rar

?????文件???????3387??2008-06-18?18:01??orl\s1\pgm\Test1.dsp

?????文件????????533??2008-06-18?18:01??orl\s1\pgm\Test1.dsw

?????文件??????41984??2008-08-01?16:52??orl\s1\pgm\Test1.ncb

?????文件???????1427??2008-07-05?11:25??orl\s1\pgm\Test1.plg

?????文件????????923??2008-07-05?11:25??orl\s1\pgm\Test1.c

?????文件?????218112??2008-08-01?16:52??orl\s1\pgm\Test1.opt

?????文件??????10318??1994-04-18?21:17??orl\s1\pgm\a\1.pgm

?????文件??????33792??2008-07-05?11:25??orl\s1\pgm\Debug\vc60.idb

?????文件??????53248??2008-07-05?11:25??orl\s1\pgm\Debug\vc60.pdb

?????文件?????175656??2008-06-18?21:10??orl\s1\pgm\Debug\Test1.pch

?????文件???????4302??2008-07-05?11:25??orl\s1\pgm\Debug\Test1.obj

?????文件?????180282??2008-07-05?11:25??orl\s1\pgm\Debug\Test1.exe

?????文件?????451584??2008-07-05?11:25??orl\s1\pgm\Debug\Test1.pdb

?????文件?????210672??2008-07-05?11:25??orl\s1\pgm\Debug\Test1.ilk

?????文件??????10318??1994-04-18?21:17??orl\s1\pgm\Debug\a\1.pgm

?????文件??????10318??1994-04-18?21:18??orl\s10\1.pgm

?????文件??????10318??1994-04-18?21:07??orl\s10\10.pgm

............此處省略437個文件信息