% Script: EiffelFit.m
%  after generating [x y] vectors of curve location,
%  then compute a least squares fit of degree d using
%  matlab functions. 
%   x0 and y0 are origin location
%   lenscale is normalization to physical scale
  clear all;
  close all;
  eiffel = imread('Eiffel.jpg');
  imshow(eiffel)
  disp('Click on 6 input points on the curve')
  [x y] = ginput(6)  % click 6 points on a curve, end is auto
  x0 = 321; y0 = 241;    % origin at middle of VGA image
  lenscale = 12;         % 12 pixels/meter?
  d = 2;                 % degree of 
  xs = (x-x0)/lenscale; ys = (y-y0)/lenscale;
  c = polyfit(xs,ys,d);
  xvals = linspace(min(xs),max(xs));
  yvals = polyval(c,xvals);
  figure
  plot(xvals,yvals,xs,ys,'o')