Mercurial > forge
changeset 10739:7ffd9112104b octave-forge
xcorr2: remove old coeff option code, replace by new method
| author | carandraug |
|---|---|
| date | Wed, 29 Aug 2012 02:45:12 +0000 |
| parents | bc121b646499 |
| children | a9fd789b543e |
| files | main/signal/NEWS main/signal/inst/xcorr2.m |
| diffstat | 2 files changed, 24 insertions(+), 14 deletions(-) [+] |
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--- a/main/signal/NEWS Mon Aug 27 13:28:45 2012 +0000 +++ b/main/signal/NEWS Wed Aug 29 02:45:12 2012 +0000 @@ -18,8 +18,8 @@ ** Bugfix in `xcorr2' introduced in 1.1.2 that would not accept "none" as scale option. - ** `xcorr2' accepts a new scale option, "norm", to return the normalized - cross correlation. + ** `xcorr2' scaling option "coeff" was changed to return the normalized + cross-correlation. ** The following functions are new: movingrms schtrig clustersegment
--- a/main/signal/inst/xcorr2.m Mon Aug 27 13:28:45 2012 +0000 +++ b/main/signal/inst/xcorr2.m Wed Aug 29 02:45:12 2012 +0000 @@ -41,10 +41,6 @@ ## element. ## ## @item "coeff" -## Normalizes the sequence dividing by the max of the cross-correlation, so that -## the largest cross-correlation element is 1. -## -## @item "norm" ## Returns the normalized cross-correlation. ## @end table ## @@ -75,7 +71,7 @@ ## bias routines by Dave Cogdell (cogdelld@asme.org) ## optimized by Paul Kienzle (pkienzle@users.sf.net) - ## norm routine by Carnë Draug (carandraug+dev@gmail.com) + ## coeff routine by Carnë Draug (carandraug+dev@gmail.com) switch lower (biasflag) case {"none"} ## do nothing, it's all done @@ -94,15 +90,10 @@ c = c./bias; case {"coeff"} - c = c/max(c(:))'; - - case {"norm"} - ## FIXME maybe these conversions for double can be removed when - ## https://savannah.gnu.org/bugs/?37199 gets fixed? a = double (a); b = double (b); a = conv2 (a.^2, ones (size (b))); - b = dot (b(:), b(:)); + b = sumsq (b(:)); c(:,:) = c(:,:) ./ sqrt (a(:,:) * b); otherwise @@ -110,7 +101,7 @@ endswitch endfunction -%!test +%!test # basic usage %! a = magic (5); %! b = [6 13 22; 10 18 23; 8 15 23]; %! c = [391 807 519 391 473 289 120 @@ -121,3 +112,22 @@ %! 473 1006 1643 1457 946 347 108 %! 242 539 850 477 374 129 54]; %! assert (xcorr2 (a, b), c); + +%!shared a, b, c, row_shift, col_shift +%! row_shift = 18; +%! col_shift = 20; +%! a = randi (255, 30, 30); +%! b = a(row_shift-10:row_shift, col_shift-7:col_shift); +%! c = xcorr2 (a, b, "coeff"); +%!assert (nthargout ([1 2], @find, c == max (c(:))), {row_shift, col_shift}); # should return exact coordinates +%! m = rand (size (b)) > 0.5; +%! b(m) = b(m) * 0.95; +%! b(!m) = b(!m) * 1.05; +%! c = xcorr2 (a, b, "coeff"); +%!assert (nthargout ([1 2], @find, c == max (c(:))), {row_shift, col_shift}); # even with some small noise, should return exact coordinates + +%!test # coeff of autocorrelation must be same as negavtive of correlation by additive inverse +%! a = 10 * randn (100, 100); +%! auto = xcorr2 (a, "coeff"); +%! add_in = xcorr2 (a, -a, "coeff"); +%! assert ([min(auto(:)), max(auto(:))], -[max(add_in(:)), min(add_in(:))]);