www.pudn.com > fvsmatlabsourcecodebyRF.rar > centralizing.m

function [Outputprint,XofCenter,YofCenter] = centralizing(fingerprint,ctrl) 
%	 modified by PRTsinghua@hotmail.com 
 
imgN=size(fingerprint,1); 
imgM=size(fingerprint,2); 
 
image = wiener2(fingerprint,[3 3]); 
[Gx,Gy] = gradient(image); 
orientnum = wiener2(2.*Gx.*Gy,[3 3]); 
orientden = wiener2((Gx.^2) - (Gy.^2),[3 3]); 
W = 8; 
ll = 9; 
orient = zeros(imgN/W,imgM/W); 
%----------------------------------------------- 
points=(imgN/W)*(imgM/W); 
for i = 1:1:points 
    x = floor((i-1)/(imgM/W))*W+1; 
    y = mod(i-1,(imgN/W))*W+1; 
    numblock = orientnum(y:y+W-1,x:x+W-1); 
    denblock = orientden(y:y+W-1,x:x+W-1); 
     
    somma_num=sum(sum(numblock)); 
    somma_denom=sum(sum(denblock)); 
     
    if somma_denom ~= 0 
        inside = somma_num/somma_denom; 
        angle = 0.5*atan(inside); 
    else 
        angle = pi/2; 
    end 
    % each block 
    if angle < 0 
        if somma_num < 0 
            angle = angle + pi/2; 
        else 
            angle = angle + pi; 
        end 
    else 
        if somma_num > 0 
            angle = angle + pi/2; 
        end 
    end 
    orient(1+(y-1)/W,1+(x-1)/W) = angle;    
end 
 
binarize = (orient < pi/2); 
[bi,bj] = find(binarize); 
xdir = zeros(W,W); 
ydir = zeros(W,W); 
for k = 1:1:size(bj,1) 
    i = bj(k); 
    j = bi(k); 
    if orient(j,i) < pi/2 
        x = fix(ll*cos(orient(j,i)-pi/2)/(W/2)); 
        y = fix(ll*sin(orient(j,i)-pi/2)/(W/2)); 
        xdir(j,i) = i-x; 
        ydir(j,i) = j-y; 
         
    end 
end 
 
binarize2 = zeros(imgN/W,imgM/W); 
for i = 1:1:size(bj,1) 
    x = bj(i); 
    y = bi(i); 
    if ~(xdir(y,x) < 1 | ydir(y,x) < 1 | xdir(y,x) > imgM/W | ydir(y,x) > imgN/W) 
        while binarize(ydir(y,x),xdir(y,x)) > 0 
            xtemp = xdir(y,x); 
            ytemp = ydir(y,x); 
            if xtemp < 1 | ytemp < 1 | xtemp > imgM/W | ytemp > imgN/W 
                break; 
            end 
            x = xtemp; 
            y = ytemp; 
            if xdir(y,x) < 1 | ydir(y,x) < 1 | xdir(y,x) > imgM/W | ydir(y,x) > imgN/W 
                if x-1 > 0 
                    while binarize(y,x-1) > 0 
                        x = x-1; 
                        if x-1 < 1 
                            break; 
                        end 
                    end 
                end 
                break; 
            end 
        end 
    end 
    binarize2(y,x) = binarize2(y,x)+1; 
end 
 
[temp,y] = max(binarize2(1:end-7,:)); 
[temp2,x] = max(temp); 
angle = orient(y(x),x)-pi/2; 
XofCenter=round(x*W-(W/2)-(ll/2)*cos(angle)); 
YofCenter=round(y(x)*W-(W/2)-(ll/2)*sin(angle)); 
Outputprint=binarize2;