10/11 Notes
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A fingerprint is an Oriented texture pattern

Oriendted Texture (FFT Method)
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Orientation (range = [0,pi))

Frequency = frequency of ridges

w(x,y) = Amplitude x cos(2pi x frequency x (xcos(theta) + ysin(theta)))

Example
 * A = 150
 * freq = 1/8 (approx)
 * theta = pi / 4
 
for i = 1 : 11
for j = 1 : 11

w(i, j)


Coordinates for image domain
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row by column, not x by y

so top left is (0,0)


What is Amplitude, freq, and theta? (FFT Method)
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image (spatial domain) -- fast fourier transform --> frequency domain == W(u,v)

frequency = distance between center of W and bright spot (impulse) = sqrt((u^)^2 + (v^)^2)

theta = angle of frequency line and x axis = arctan(v^ / u^)

W(u^, v^) = brightest pixel location

Amplitude = color value of W(u^, v^) = abs(W(u^, v^))