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changed default parameters of SURF, which improved its performance. Restored bi-linear interpolation in SURF descriptor extractor. Added test for SURF homography + check for non-zero (positive) responses.

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This commit is contained in:
Vadim Pisarevsky
2013-01-30 18:07:37 +04:00
parent 7e5f877ad9
commit 1f261c2f9d
3 changed files with 40 additions and 5 deletions
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modules/nonfree/src/surf.cpp
+34 -3
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@@ -698,11 +698,12 @@ struct SURFInvoker
cvGetQuadrangleSubPix( img, &win, &W );
*/
// Nearest neighbour version (faster)
float win_offset = -(float)(win_size-1)/2;
float start_x = center.x + win_offset*cos_dir + win_offset*sin_dir;
float start_y = center.y - win_offset*sin_dir + win_offset*cos_dir;
uchar* WIN = win.data;
#if 0
// Nearest neighbour version (faster)
for( i = 0; i < win_size; i++, start_x += sin_dir, start_y += cos_dir )
{
float pixel_x = start_x;
@@ -714,6 +715,36 @@ struct SURFInvoker
WIN[i*win_size + j] = img->at<uchar>(y, x);
}
}
#else
int ncols1 = img->cols-1, nrows1 = img->rows-1;
size_t imgstep = img->step;
for( i = 0; i < win_size; i++, start_x += sin_dir, start_y += cos_dir )
{
double pixel_x = start_x;
double pixel_y = start_y;
for( j = 0; j < win_size; j++, pixel_x += cos_dir, pixel_y -= sin_dir )
{
int ix = cvFloor(pixel_x), iy = cvFloor(pixel_y);
if( (unsigned)ix < (unsigned)ncols1 &&
(unsigned)iy < (unsigned)nrows1 )
{
float a = (float)(pixel_x - ix), b = (float)(pixel_y - iy);
const uchar* imgptr = &img->at<uchar>(iy, ix);
WIN[i*win_size + j] = (uchar)
cvRound(imgptr[0]*(1.f - a)*(1.f - b) +
imgptr[1]*a*(1.f - b) +
imgptr[imgstep]*(1.f - a)*b +
imgptr[imgstep+1]*a*b);
}
else
{
int x = std::min(std::max(cvRound(pixel_x), 0), ncols1);
int y = std::min(std::max(cvRound(pixel_y), 0), nrows1);
WIN[i*win_size + j] = img->at<uchar>(y, x);
}
}
}
#endif
}
else
{
@@ -844,10 +875,10 @@ struct SURFInvoker
SURF::SURF()
{
hessianThreshold = 100;
extended = true;
extended = false;
upright = false;
nOctaves = 4;
nOctaveLayers = 2;
nOctaveLayers = 3;
}
SURF::SURF(double _threshold, int _nOctaves, int _nOctaveLayers, bool _extended, bool _upright)