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to perform iris normalisation

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Tharini
Tharini el 14 de Sept. de 2011
Comentada: pawarcse el 4 de Jul. de 2017
Need matlab code to perform irid normalisation

Respuestas (2)

Walter Roberson
Walter Roberson el 14 de Sept. de 2011

omar mohamed
omar mohamed el 10 de Dic. de 2012
Editada: Walter Roberson el 29 de Jun. de 2017
function imP = ImToPolar (imR, rMin, rMax, M, N)
% IMTOPOLAR converts rectangular image to polar form. The output image is
% an MxN image with M points along the r axis and N points along the theta
% axis. The origin of the image is assumed to be at the center of the given
% image. The image is assumed to be grayscale.
% Bilinear interpolation is used to interpolate between points not exactly
% in the image.
%
% rMin and rMax should be between 0 and 1 and rMin < rMax. r = 0 is the
% center of the image and r = 1 is half the width or height of the image.
%
% V0.1 7 Dec 2007 (Created), Prakash Manandhar pmanandhar@umassd.edu
[Mr Nr] = size(imR); % size of rectangular image
Om = (Mr+1)/2; % co-ordinates of the center of the image
On = (Nr+1)/2;
sx = (Mr-1)/2; % scale factors
sy = (Nr-1)/2;
imP = zeros(M, N);
delR = (rMax - rMin)/(M-1);
delT = 2*pi/N;
% loop in radius and
for ri = 1:M
for ti = 1:N
r = rMin + (ri - 1)*delR;
t = (ti - 1)*delT;
x = r*cos(t);
y = r*sin(t);
xR = x*sx + Om;
yR = y*sy + On;
imP (ri, ti) = interpolate (imR, xR, yR);
end
end
function v = interpolate (imR, xR, yR)
xf = floor(xR);
xc = ceil(xR);
yf = floor(yR);
yc = ceil(yR);
if xf == xc & yc == yf
v = imR (xc, yc);
elseif xf == xc
v = imR (xf, yf) + (yR - yf)*(imR (xf, yc) - imR (xf, yf));
elseif yf == yc
v = imR (xf, yf) + (xR - xf)*(imR (xc, yf) - imR (xf, yf));
else
A = [ xf yf xf*yf 1
xf yc xf*yc 1
xc yf xc*yf 1
xc yc xc*yc 1 ];
r = [ imR(xf, yf)
imR(xf, yc)
imR(xc, yf)
imR(xc, yc) ];
a = A\double(r);
w = [xR yR xR*yR 1];
v = w*a;
end
end
  3 comentarios
Walter Roberson
Walter Roberson el 29 de Jun. de 2017
Mr and Nr will be assigned the size of the input image iMR.
Note: iMR should be 2D (grayscale) not RGB.
pawarcse
pawarcse el 4 de Jul. de 2017
Thank you very much sir!!

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