sugr_ghm_update_homography

% GHM update spectrally normalized homography

 Hu = sugr_ghm_update_homography(Ha,k)

 * Ha = N x N matrix, approximate values
 * k  = N^2-1-vector, reduced corrections 

 Hu = updated matrix

 Wolfgang Förstner 03/2011
 wfoerstn@uni-bonn.de

0001 %% GHM update spectrally normalized homography
0002 %
0003 % Hu = sugr_ghm_update_homography(Ha,k)
0004 %
0005 % * Ha = N x N matrix, approximate values
0006 % * k  = N^2-1-vector, reduced corrections
0007 %
0008 % Hu = updated matrix
0009 %
0010 % Wolfgang Förstner 03/2011
0011 % wfoerstn@uni-bonn.de
0012 
0013 function Hu = sugr_ghm_update_homography(Ha,k)
0014 
0015 % dimension
0016 N = size(Ha,1);
0017 
0018 % K = traceless matrix
0019 K      = reshape([k;0],N,N);
0020 K(N,N) = -trace(K);
0021 
0022 % update
0023 Hu = expm(K)*Ha;
0024