how can i write matlab code for recursive mean separation histogram equlization without using inbuilt functions

//----main module-----// PicOri=imread('C:\Users\Public\Pictures\Sample Pictures\image14.jpg'); % if isgray(PicOri)==0 PicGray=rgb2gray(PicOri); % else % PicGray=PicOri; % end figure(1),imshow(PicGray),title('Ô­»Ò¶ÈͼÏñ');

h=imhist(PicGray); % figure(2),plot(h),title('ԭͼÏñÖ±·½Í¼');

[m,n]=size(PicGray); PicHEt=zeros(m,n);

max = double(max(PicGray(:))); min = double(min(PicGray(:)));

r=1; length=2^r; Xm=zeros(1,length); Xm(1)=max+1; Xm(2)=min+1;

for i=1:r for j=1:2^(i-1) Xm(2^(i-1)+j+1)= averpixcal(h,Xm(2^(i-1)-j+2),Xm(2^(i-1)-j+1)); end Xm=sort(Xm,'descend'); end Xm=sort(Xm);

for i=2:2^r [row,col]=find((PicGray>=Xm(i-1)-1)&(PicGray<=Xm(i)-2)); PicHEt=FuncHE(PicGray,PicHEt,row,col,h,Xm(i-1)-1,Xm(i)-2,m,n); end [row,col]=find((PicGray>=Xm(2^r)-1)&(PicGray<=Xm(2^r+1)-1)); PicHEt=FuncHE(PicGray,PicHEt,row,col,h,Xm(2^r)-1,Xm(2^r+1)-1,m,n);

PicHE=uint8(PicHEt); h1=imhist(PicHE); figure(3),imshow(PicHE),title('¾ùºâºóµÄͼÏñ'); figure(4),plot(h1),title('¾ùºâºóµÄÖ±·½Í¼'); ---------------------------------------------------------------------------------

//---function averpixcal----// function Xm=averpixcal(h,begin,ending)

PixSum=0; Sum=0; for i=begin:ending PixSum=(i-1)*h(i)+PixSum; Sum=h(i)+Sum; end Xm= double(round(PixSum/Sum)) -----------------------------------------------------------------------------------

//-----function to find the histogram equalization-------// function PicHEt=FuncHE(PicGray,PicHEt,row,col,h,min,max,m,n)

pix=size(col,1);

%PZ=zeros(1,Xm(2)-1); PZ=zeros(1,max-min+1);

for i=min+1:max+1 PZ(i-min)=h(i)/pix; end

%S=zeros(1,Xm(2)-1); S=zeros(1,max+1);

S(min+1)=PZ(1); for i=min+2:max+1 S(i)=PZ(i-min)+S(i-1); end

FuncHE=min+(max-min)*S;

for k=1:pix PicHEt(row(k),col(k))=floor(FuncHE(PicGray(row(k),col(k))+1)); end