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changeset 11419:c8b7b87a88a4 octave-forge

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cp2tform: avoid svd decomposition for performance (patch by Pantxo Diribarne) (bug #38179).
author carandraug
date Tue, 29 Jan 2013 09:17:31 +0000
parents ed31a7de4a80
children 354517fa551d
files main/image/inst/cp2tform.m
diffstat 1 files changed, 5 insertions(+), 4 deletions(-) [+]
line wrap: on
line diff
--- a/main/image/inst/cp2tform.m	Mon Jan 28 20:15:39 2013 +0000
+++ b/main/image/inst/cp2tform.m	Tue Jan 29 09:17:31 2013 +0000
@@ -205,10 +205,11 @@
       tmp1 = ones(size(u));
       A = [-u -v -tmp1 tmp0 tmp0 tmp0 x.*u x.*v x;
            tmp0 tmp0 tmp0 -u -v -tmp1 y.*u y.*v y];
-      [U S V] = svd (A);
-      tmat = V(:,end);
+      B = - A(:,end);
+      A(:,end) = [];
+      tmat = A\B;
+      tmat(9) = 1;
       tmat = reshape (tmat, 3, 3);
-      tmat = tmat./tmat(end,end);
       trans = maketform ("projective", tmat);
 
     case "polynomial"
@@ -289,7 +290,7 @@
 
 
 %!test
-%! npt = 10000;
+%! npt = 100000;
 %! [crw, cap] = coords (npt);
 %! ttype = 'projective';
 %! T = cp2tform (crw, cap, ttype);