camcald4.m

这是一个基于MATLAB的机器视觉工具箱,里面用很多非常有价值的的程序

% CAMCALD4	Compute partial camera calibration from four coplanar data points
%
%	C = CAMCALD4(D)
% 
% Solve the camera calibration using a least squares technique.  Input is a table 
% of data points, D, with each row of the form [x y iX iY] where (x,y) is the world
% coordinate of the point within the plane, and (iX, iY) is the image plane 
% coordinate.
%
% Output is a 3x3 partial camera calibration matrix (missing the usual third column).
%
% SEE ALSO: CAMPOSE4, CAMCALP, CAMERA, CAMCALT, INVCAMCAL
%
%
%	Copyright (c) Peter Corke, 1999  Machine Vision Toolbox for Matlab

%		pic 4/93
function t = camcald4(m)

	[rows,cols] = size(m);

	if (rows ~= 4) | (cols ~= 4)
		error('data matrix should be 4 x 4')
	end
%
% build the matrix as per Ballard and Brown p.482
%
% the row pair are one row at this point
%
	aa = [ m(:,1) m(:,2) ones(rows,1) zeros(rows,3)   ...
	       -m(:,3).*m(:,1) -m(:,3).*m(:,2)    ...
		zeros(rows,3) m(:,1) m(:,2)  ones(rows,1)  ...
	       -m(:,4).*m(:,1) -m(:,4).*m(:,2) ];
%
% reshape the matrix, so that the rows interleave
%

	aa = reshape(aa', 8, rows*2)';

	bb = reshape( [m(:,3) m(:,4)]', 1, rows*2)';

	t = aa\bb;
	t = reshape([t;1]',3,3)';