matlab如何实现中值滤波？

i=imread('face1.jpg');
I=rgb2gray(i);
BW=im2bw(I);
figure,imshow(BW)
[n1 n2]=size(BW);
r=floor(n1/10);
c=floor(n2/10);
x1=1;x2=r;
s=r*c; 
for i=1:10
    y1=1;y2=c;
    for j=1:10
        if (y2<=c | y2>=9*c) | (x1==1 | x2==r*10)
            loc=find(BW(x1:x2, y1:y2)==0);
            [o p]=size(loc);
            pr=o*100/s;
            if pr<=100
                BW(x1:x2, y1:y2)=0;
                r1=x1;r2=x2;s1=y1;s2=y2;
                pr1=0;
            end
            imshow(BW);
        end
            y1=y1+c;
            y2=y2+c;
    end
 
 x1=x1+r;
 x2=x2+r;
end
 figure,imshow(BW)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%% detection of face object
 
L = bwlabel(BW,8);
BB  = regionprops(L, 'BoundingBox');
BB1=struct2cell(BB);
BB2=cell2mat(BB1);
 
[s1 s2]=size(BB2);
mx=0;
for k=3:4:s2-1
    p=BB2(1,k)*BB2(1,k+1);
    if p>mx & (BB2(1,k)/BB2(1,k+1))<1.8
        mx=p;
        j=k;
    end
end
figure,imshow(I);
hold on;
rectangle('Position',[BB2(1,j-2),BB2(1,j-1),BB2(1,j),BB2(1,j+1)],'EdgeColor','r' )

function varargout = FR_Processed_histogram(varargin)
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @FR_Processed_histogram_OpeningFcn, ...
                   'gui_OutputFcn',  @FR_Processed_histogram_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end
 
if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT
 
%--------------------------------------------------------------------------
% --- Executes just before FR_Processed_histogram is made visible.
function FR_Processed_histogram_OpeningFcn(hObject, eventdata, handles, varargin)
 
handles.output = hObject;
 
% Update handles structure
guidata(hObject, handles);
 
% UIWAIT makes FR_Processed_histogram wait for user response (see UIRESUME)
% uiwait(handles.figure1);
global total_sub train_img sub_img max_hist_level bin_num form_bin_num;
 
total_sub = 40;
train_img = 200;
sub_img = 10;
max_hist_level = 256;
bin_num = 9;
form_bin_num = 29;
%--------------------------------------------------------------------------
% --- Outputs from this function are returned to the command line.
function varargout = FR_Processed_histogram_OutputFcn(hObject, eventdata, handles) 
varargout{1} = handles.output;
 
%--------------------------------------------------------------------------
% --- Executes on button press in train_button.  
function train_button_Callback(hObject, eventdata, handles)
global train_processed_bin;
global total_sub train_img sub_img max_hist_level bin_num form_bin_num;
 
train_processed_bin(form_bin_num,train_img) = 0;
K = 1;
train_hist_img = zeros(max_hist_level, train_img);
 
for Z=1:1:total_sub 
  for X=1:2:sub_img    %%%train on odd number of images of each subject
 
    I = imread( strcat('ORL\S',int2str(Z),'\',int2str(X),'.bmp') );        
    [rows cols] = size(I);
 
    for i=1:1:rows
       for j=1:1:cols
           if( I(i,j) == 0 )
               train_hist_img(max_hist_level, K) =  train_hist_img(max_hist_level, K) + 1;                            
           else
               train_hist_img(I(i,j), K) = train_hist_img(I(i,j), K) + 1;                         
           end
       end   
    end   
     K = K + 1;        
  end  
 end  
 
[r c] = size(train_hist_img);
sum = 0;
for i=1:1:c
    K = 1;
   for j=1:1:r        
        if( (mod(j,bin_num)) == 0 )
            sum = sum + train_hist_img(j,i);            
            train_processed_bin(K,i) = sum/bin_num;
            K = K + 1;
            sum = 0;
        else
            sum = sum + train_hist_img(j,i);            
        end
    end
    train_processed_bin(K,i) = sum/bin_num;
end
 
display ('Training Done')
save 'train'  train_processed_bin;
 
%--------------------------------------------------------------------------
% --- Executes on button press in Testing_button.    
function Testing_button_Callback(hObject, eventdata, handles)
global train_img max_hist_level bin_num form_bin_num;
global train_processed_bin;
global filename pathname I
 
load 'train'
test_hist_img(max_hist_level) = 0;
test_processed_bin(form_bin_num) = 0;
 
 
 [rows cols] = size(I);
 
    for i=1:1:rows
       for j=1:1:cols
           if( I(i,j) == 0 )
               test_hist_img(max_hist_level) =  test_hist_img(max_hist_level) + 1;                            
           else
               test_hist_img(I(i,j)) = test_hist_img(I(i,j)) + 1;                         
           end
       end   
    end   
 
  [r c] = size(test_hist_img);
  sum = 0;
 
    K = 1;
    for j=1:1:c        
        if( (mod(j,bin_num)) == 0 )
            sum = sum + test_hist_img(j);            
            test_processed_bin(K) = sum/bin_num;
            K = K + 1;
            sum = 0;
        else
            sum = sum + test_hist_img(j);            
        end
    end
 
 test_processed_bin(K) = sum/bin_num;
 
sum = 0;
K = 1;
 
    for y=1:1:train_img
        for z=1:1:form_bin_num        
          sum = sum + abs( test_processed_bin(z) - train_processed_bin(z,y) );  
        end         
        img_bin_hist_sum(K,1) = sum;
        sum = 0;
        K = K + 1;
    end
 
    [temp M] = min(img_bin_hist_sum);
    M = ceil(M/5);
    getString_start=strfind(pathname,'S');
    getString_start=getString_start(end)+1;
    getString_end=strfind(pathname,'\');
    getString_end=getString_end(end)-1;
    subjectindex=str2num(pathname(getString_start:getString_end));
 
    if (subjectindex == M)
      axes (handles.axes3)
      %image no: 5 is shown for visualization purpose
      imshow(imread(STRCAT('ORL\S',num2str(M),'\5.bmp')))    
      msgbox ( 'Correctly Recognized');
    else
     display ([ 'Error==>  Testing Image of Subject >>' num2str(subjectindex) '  matches with the image of subject >> '  num2str(M)])
     axes (handles.axes3)
     %image no: 5 is shown for visualization purpose
     imshow(imread(STRCAT('ORL\S',num2str(M),'\5.bmp')))    
     msgbox ( 'Incorrectly Recognized');
    end
 
display('Testing Done')
%--------------------------------------------------------------------------
function box_Callback(hObject, eventdata, handles)
function box_CreateFcn(hObject, eventdata, handles)
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end
%--------------------------------------------------------------------------
% --- Executes on button press in Input_Image_button.
function Input_Image_button_Callback(hObject, eventdata, handles)
% hObject    handle to Input_Image_button (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global filename pathname I
[filename, pathname] = uigetfile('*.bmp', 'Test Image');
axes(handles.axes1)
imgpath=STRCAT(pathname,filename);
 
I = imread(imgpath);
imshow(I)
 
%--------------------------------------------------------------------------
% --- Executes during object creation, after setting all properties.
function axes3_CreateFcn(hObject, eventdata, handles)