Help me understand a program for orientation image like fingerprint

Hi! I had a problem on frequency estimation.

The error written on the command window is 'Index exceeds matrix dimensions'.

Hope anyone can solve this problem. Thanks in advance.

Fingerprint Help?

MATLAB?

Type your error message into MATLAB's help search, and you will find this:
"If you try to use the value of an element outside of the matrix, it is an error: ... Index exceeds matrix dimensions."

Re: Fingerprint Help?

Hi

Can anyone help me about image Fingerprint orientation.

this is my implementation base on Raymond THai thesis

regards

Re: Fingerprint Help?

have done a pro on fingerprint recognition..
I have not used any orientation estimation.. Ramyond Thai is not a very good paper. Only the starting part of the paper is good...
U can download my report.. part2.pdf which is loaded in the forum.

Re: Fingerprint Help?

Hi

Can you get me your address of your paper

Re: Fingerprint Help?

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;

Fingerprint Help?

Hi again zahedpoor

Can you maybe post the paper/link of peter's paper from Wau university so that i can see what he is actually doing and what you want to do .

Regards
KoosDoos

Re: Fingerprint Help?

Hi Koosdoos

excuseme bacause I'm late,

thanks 4 replying me,

in here u can find som following functions

h**p://www.csse.uwa.edu.au/~pk/Research/MatlabFns/


ridgesegment.m identifies ridge-like regions of a fingerprint image. It also normalises the intensity values of the image.
ridgeorient.m estimates the local orientation of ridges in a fingerprint.
plotridgeorient.m plots ridge orientations calculated by ridgeorient.
ridgefreq.m estimates the local ridge frequency across a fingerprint image.
freqest.m estimates the ridge frequency within a small block of an image. This is used by ridgefreq.
ridgefilter.m enhances a fingerprint image using oriented filters.
Example of using these functions above.


and here is
h**p://www.csse.uwa.edu.au/~pk/studentprojects/raymondthai

the paper by reymond THai,


but what things that said in that paper does not exist in those functions, methods r difference.

thanks in advance and I'm waiting for ur answer

Re: Fingerprint Help?

I'm new in fingerprint image processing and still looking for a fingerprint scanner. Can anyone help me here?

I hope to know the recommended model as well as the price as soon as possible.

Thanks in advance!