Re: Fingerprint Image orientatiom problem

Re: Fingerprint Image orientatiom problem

this is my Implementation but not work.

Re: Fingerprint Image orientatiom problem

Hi Zahedpoor ,

What happens to the image if it is not working ?
What are you trying to do with this program exactly ?


Is this for local orientation of ridges or for global orientation ?

KoosDoos

Re: Fingerprint Image orientatiom problem

Hi

That is local and global base on Raymond Thai.

Do u know any paper that show it more exatly , in which address?

thanks
zahedpoor

Added after 6 minutes:

Hi Koosdoos

Thanks for replying me.

Im = image and blksize=block size =16

first I calculate local from i,j-w/2 to j,j+w/2 and find local eith theta and finally estimate global orientation ,

do u have any suggesstion,

zahedpoor

Re: Fingerprint Image orientatiom problem

By global orientation you mean for the whole image ?

OK , let me look through my papers and notes to see if i can help you out .

Koosdoos

Re: Fingerprint Image orientatiom problem

in Final_part2.pdf have come the formula that not work, but in Wau university by peter write a program like this for orientation image like fingerprint.

in following , I have commented som For , in that , I want to calculate formula in that pdf paper. but not work.


can u say me y it not Work with For lines?
can u say me , What is "denom" variable and how to calculate this?


regards
zahedpoor






blksize=16;
f = fspecial('sobel'); % Generate sobel filter. sobel is gradient mask,

Gx = filter2(f', im); % Gradient of the image in x
Gy = filter2(f, im); % ... and y

Gxy = zeros(size(im));
Gxx = zeros(size(im));
Gyy = zeros(size(im));
Gyyxx = zeros(size(im));


Gxx = Gx.^2; % Covariance data for the image gradients
Gxy = Gx.*Gy;
Gyy = Gy.^2;

% Now smooth the covariance data to perform a weighted summation of the
% data.

f = fspecial('gaussian', 18,3);
Gxx = filter2(f, Gxx);
Gxy = 2*filter2(f, Gxy);
Gyy = filter2(f, Gyy);

% Analytic solution of principal direction
denom = sqrt(Gxy.^2 + (Gxx - Gyy).^2) + eps;
sin2theta = Gxy./denom; % Sine and cosine of doubled angles
cos2theta = (Gxx-Gyy)./denom;


% n=blksize/2;
%
% [rows,cols]=size(im);
%
%
% for i=n+1:rows-n
% for j=n+1:cols-n
% Gxy(i,j)=Gxy(i,j)+ sum(sum( 2* Gx(i-n:i+n,j-n:j+n) .* Gy(i-n:i+n,j-n:j+n) )) ;
% Gxx(i,j)=Gxx(i,j)+ sum(sum( Gx(i-n:i+n,abs(j-n):j+n).^2 )) ;
% Gyy(i,j)=Gyy(i,j)+ sum(sum( Gy(i-n:i+n,abs(j-n):j+n).^2 )) ;
% Gyyxx(i,j)= Gyyxx(i,j)+ sum(sum( Gxx(i-n:i+n,abs(j-n):j+n) .* Gyy(i-n:i+n,abs(j-n):j+n) ));
% end
% end



%theta=atan2( (Gxx .* Gyy), 2 .* Gxy)/2;

%SMOOTHING the local neighbourhood base on x and y

f=fspecial('gaussian',8,1);
% theta = imfilter(theta ,f) ;
%
%
% cos2theta = cos(2*theta);
% sin2theta = sin(2*theta);

%final smoothed orientation image

cos2theta = imfilter(cos2theta ,f) ;
sin2theta = imfilter(sin2theta ,f);


Orientim= pi/2+atan2(sin2theta , cos2theta)/2;

Re: Fingerprint Image orientatiom problem

would u please describe more


regards
zahdpoor