static bool SIFTDetector(const Image<unsigned char>& I,
std::vector<SIOPointFeature>& feats,
std::vector<Descriptor<type,128> >& descs,
bool bDezoom = false,
bool bRootSift = false,
float dPeakThreshold = 0.04f)
{
// First Octave Index.
int firstOctave = (bDezoom == true) ? -1 : 0;
// Number of octaves.
int numOctaves = 6;
// Number of scales per octave.
int numScales = 3;
// Max ratio of Hessian eigenvalues.
float edgeThresh = 10.0f;
// Min contrast.
float peakThresh = dPeakThreshold;
int w=I.Width(), h=I.Height();
//Convert to float
Image<float> If( I.GetMat().cast<float>() );
vl_constructor();
VlSiftFilt *filt = vl_sift_new(w,h,numOctaves,numScales,firstOctave);
if (edgeThresh >= 0)
vl_sift_set_edge_thresh(filt, edgeThresh);
if (peakThresh >= 0)
vl_sift_set_peak_thresh(filt, 255*peakThresh/numScales);
vl_sift_process_first_octave(filt, If.data());
vl_sift_pix descr[128];
Descriptor<type, 128> descriptor;
while (true) {
vl_sift_detect(filt);
VlSiftKeypoint const *keys = vl_sift_get_keypoints(filt);
int nkeys = vl_sift_get_nkeypoints(filt);
for (int i=0;i<nkeys;++i) {
double angles [4];
int nangles=vl_sift_calc_keypoint_orientations(filt,angles,keys+i);
for (int q=0 ; q < nangles ; ++q) {
vl_sift_calc_keypoint_descriptor(filt,descr, keys+i, angles [q]);
SIOPointFeature fp;
fp.x() = keys[i].x;
fp.y() = keys[i].y;
fp.scale() = keys[i].sigma;
fp.orientation() = static_cast<float>(angles[q]);
siftDescToFloat(descr, descriptor, bRootSift);
descs.push_back(descriptor);
feats.push_back(fp);
}
}
if (vl_sift_process_next_octave(filt))
break; // Last octave
}
vl_sift_delete(filt);
vl_destructor();
return true;
}
SIFT_Image_describer(const SiftParams & params = SiftParams(), bool bOrientation = true)
:Image_describer(), _params(params), _bOrientation(bOrientation)
{
vl_constructor();
}
