mtalab实现基于傅里叶描述子的树叶识别

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Leaf Classify

QIN, Yujie

03.11.2009

1. Grundlegenden Funktionen

%function plotFD(F)

% F: The (non-normalised) Fourier descriptor of a contour

U = [U U(1)];

plot(U);

end

end

%function [G]=shiftFD(F, x, y)

% F: The (non-normalised) Fourier descriptor of a contour

% x: X-Translation

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% y: Y-Translation

% G: The (non-normalised) Fourier descriptor of the shifted contour

G(1)=F(1) + N .* (x + y*i);

end

%function [G]=scaleFD(F,scaleFactor)

% F: The (non-normalised) Fourier descriptor of a contour

% scaleFactor: Change in contour scale

% G: The (non-normalised) Fourier descriptor of the scaled contour

% Scales the contour corresponding to F by 100*scaleFactor %.

% This operation does not require an (inverse) DFT!

% G: The a resized Fourier descriptor with n elements

% Processes F to obtain G, which has been shortened to contain only n

% elements (assume F has more than n elements).

function [G]=resizeFD(F, n)

G=F;

len=length(F);

if (len > n)

T1=fftshift(F);

p=round((len-n) ./ 2);

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end

% G: The normalised, invariant Fourier descriptor of the contour

% Processes F to obtain G, which is invariant to translation,

% rotation and scaling of the original contour.

function [G]=normaliseFD(F)

T=F;

%Translation Invariance

T(1)=0;

%Scale Invariance

si=abs(T(2));

T=T ./ si;

%Rotation and changes in starting point

T=abs(T);

%Output the result

%function [diff]=compareFD(F, G)

% diff: A measure of the difference between F and G

% Quantifies the difference between F and G (see lecture notes)

diff = -1;

if (length(F) == length(G))

diff = sum((abs(F-G)) .^ 2);

end

end