orient.m

一个很好的人脸识别系统

% Computes the inclination angle of the segmented region.
% according to the centroid coordinates (xmean, ymean), and
% the segmented region itself.
% See reference [5] in the references section for more details.

function [theta] = orient(bw,xmean,ymean)
[m n] =size(bw);
bw=double(bw);

a = 0; b = 0; c = 0;
for i=1:m,
  for j=1:n,
     a = a + (j - xmean)^2 * bw(i,j);    
     b = b + (j - xmean) * (i - ymean) * bw(i,j);
     c = c + (i - ymean)^2 * bw(i,j);    
  end;
end;
b = 2 * b;

theta = atan(b/(a-c))/2;

% change from radians to degrees.
theta = theta*(180/pi);