function fea=humanFeaExtract(im, opt, showPlot)
% feaExtract: Feature extraction for human images
%
%	Usage:
%		fea=humanFeaExtract(imFile, opt, showPlot)
%
%	Example:
%		imFile='TrainingDatas216.png';
%		im=imread(imFile);
%		opt=humanFeaExtract('defaultOpt');
%		fea=humanFeaExtract(im, opt, 1);

%	Category: Human image feature extraction
%	Roger Jang, 20150110

if nargin<1, selfdemo; return; end
if ischar(im) && strcmpi(im, 'inputName')	% Return the input names
	fea={'fd1', 'fd2', 'fd3', 'fd4', 'fd5', 'fd6', 'fd7', 'fd8'};
	return
end
if ischar(im) && strcmpi(im, 'defaultOpt')	% Set the default options
	fea.dim=8;		% Dummy field to be added later
	return
end
if nargin<2||isempty(opt), opt=feval(mfilename, 'defaultOpt'); end
if nargin<3, showPlot=0; end

% To get binary image
im=im2double(im);
imBw = im2bw(im, graythresh(im));

% To find boundary of main's object which has the largest length
boundarySet = bwboundaries(imBw, 'noholes');
leng = zeros(length(boundarySet),1);
for i=1:length(boundarySet)
    leng(i)=length(boundarySet{i}); 
end
[junk, maxId] = max(leng);
boundaryPos=boundarySet{maxId};

% FFT transform
X_points = boundaryPos(:,2);
Y_points = boundaryPos(:,1);
x_fft = fft(X_points);
y_fft = fft(Y_points);

% computing magnitude value
magnitude_X = abs(x_fft);
magnitude_Y = abs(y_fft);

% computing magnitude of Fourier Descriptors
R = sqrt(magnitude_X.^2 + magnitude_Y.^2);
first_conponent = R(1);
other_conponents = R(2:length(R));

% Get fourier Descriptors vector
FourierDescriptors_Vector = other_conponents/first_conponent;

% Get 15 coefficiences of Fourier Descriptors
temp = FourierDescriptors_Vector(1:opt.dim);
fea=temp(:);

if showPlot
	subplot(221);imshow(im); title('Original image');
	subplot(222); imshow(imBw); title('BW image and boundary');
	for i=1:size(boundaryPos, 1)
		line(boundaryPos(i,2), boundaryPos(i, 1), 'color', 'r', 'marker', '.');
	end
	subplot(223); plot([magnitude_X(:), magnitude_Y(:)], '.-'); title('Magnitude of FFT of x and y');
	subplot(224); plot(fea, '.-'); title('Feature vector');
end

% ====== Self demo
function selfdemo
mObj=mFileParse(which(mfilename));
strEval(mObj.example);