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lib/Image/Leptonica/Func/correlscore.pm  view on Meta::CPAN

  constraint.  However, this is not particularly effective.

  The implementation here gives the same result as in
  pixCorrelationScoreSimple(), where a temporary Pix is made to hold
  the AND and implementation uses rasterop:
      pixt = pixCreateTemplate(pix1);
      pixRasterop(pixt, idelx, idely, wt, ht, PIX_SRC, pix2, 0, 0);
      pixRasterop(pixt, 0, 0, wi, hi, PIX_SRC & PIX_DST, pix1, 0, 0);
      pixCountPixels(pixt, &count, tab);
      pixDestroy(&pixt);
  However, here it is done in a streaming fashion, counting as it goes,
  and touching memory exactly once, giving a 3-4x speedup over the
  simple implementation.  This very fast correlation matcher was
  contributed by William Rucklidge.

=head2 pixCorrelationScoreShifted

l_int32 pixCorrelationScoreShifted ( PIX *pix1, PIX *pix2, l_int32 area1, l_int32 area2, l_int32 delx, l_int32 dely, l_int32 *tab, l_float32 *pscore )

  pixCorrelationScoreShifted()