GradHistChannel::GradHistChannel(const GradMagChannel& GMC)
{
int w = GMC.getWidth();
int h = GMC.getHeight();
int nChns = GMC.getnChns();
if (nChns != 1) {
std::cerr << "Number of channels should be 1 for the Magnitudes!!" << std::endl;
}
//Parameters, should be configurable
int binSize = 4; //equals shrinking
int nw = w / binSize;
int nh = h / binSize;
int nOrientations = 6;
bool full = false;
int softBin = 0;
//It is important that this memory is set to zero to avoid random values in the result
histogram = (float*)calloc(nw * nh * nOrientations, sizeof(float));
;
gradHist(GMC.getMagnitude(), GMC.getOrientation(), histogram, h, w, binSize, nOrientations, softBin, full);
setChanneldata(histogram, nw, nh, nOrientations);
}
// H=gradHist(M,O,[...]) - see gradientHist.m
void mGradHist( int nl, mxArray *pl[], int nr, const mxArray *pr[] ) {
int h, w, d, hb, wb, nChns, binSize, nOrients, softBin, useHog;
bool full; float *M, *O, *H, clipHog;
checkArgs(nl,pl,nr,pr,1,3,2,8,&h,&w,&d,mxSINGLE_CLASS,(void**)&M);
O = (float*) mxGetPr(pr[1]);
if( mxGetM(pr[1])!=h || mxGetN(pr[1])!=w || d!=1 ||
mxGetClassID(pr[1])!=mxSINGLE_CLASS ) mexErrMsgTxt("M or O is bad.");
binSize = (nr>=3) ? (int) mxGetScalar(pr[2]) : 8;
nOrients = (nr>=4) ? (int) mxGetScalar(pr[3]) : 9;
softBin = (nr>=5) ? (int) mxGetScalar(pr[4]) : 1;
useHog = (nr>=6) ? (int) mxGetScalar(pr[5]) : 0;
clipHog = (nr>=7) ? (float) mxGetScalar(pr[6]) : 0.2f;
full = (nr>=8) ? (bool) (mxGetScalar(pr[7])>0) : false;
hb = h/binSize; wb = w/binSize;
nChns = useHog== 0 ? nOrients : (useHog==1 ? nOrients*4 : nOrients*3+5);
pl[0] = mxCreateMatrix3(hb,wb,nChns,mxSINGLE_CLASS,1,(void**)&H);
if( nOrients==0 ) return;
if( useHog==0 ) {
gradHist( M, O, H, h, w, binSize, nOrients, softBin, full );
} else if(useHog==1) {
hog( M, O, H, h, w, binSize, nOrients, softBin, full, clipHog );
} else {
fhog( M, O, H, h, w, binSize, nOrients, softBin, clipHog );
}
}
void
pcl::people::HOG::compute (float *I, float *descriptor) const
{
// HOG computation:
float *M, *O, *G, *H;
M = new float[h_ * w_];
O = new float[h_ * w_];
H = new float[(w_ / bin_size_) * (h_ / bin_size_) * n_orients_]();
G = new float[(w_ / bin_size_) * (h_ / bin_size_) * n_orients_ *4]();
// Compute gradient magnitude and orientation at each location (uses sse):
gradMag (I, h_, w_, n_channels_, M, O );
// Compute n_orients gradient histograms per bin_size x bin_size block of pixels:
gradHist ( M, O, h_, w_, bin_size_, n_orients_, soft_bin_, H );
// Apply normalizations:
normalization ( H, h_, w_, bin_size_, n_orients_, clip_, G );
// Select descriptor of internal part of the image (remove borders):
int k = 0;
for (int l = 0; l < (n_orients_ * 4); l++)
{
for (int j = 1; j < (w_ / bin_size_ - 1); j++)
{
for (int i = 1; i < (h_ / bin_size_ - 1); i++)
{
descriptor[k] = G[i + j * h_ / bin_size_ + l * (h_ / bin_size_) * (w_ / bin_size_)];
k++;
}
}
}
delete[] M; delete[] O; delete[] H; delete[] G;
}
// compute HOG features
void hog( float *M, float *O, float *H, int h, int w, int binSize,
int nOrients, int softBin, bool full, float clip )
{
float *N, *R; const int hb=h/binSize, wb=w/binSize, nb=hb*wb;
// compute unnormalized gradient histograms
R = (float*) wrCalloc(wb*hb*nOrients,sizeof(float));
gradHist( M, O, R, h, w, binSize, nOrients, softBin, full );
// compute block normalization values
N = hogNormMatrix( R, nOrients, hb, wb, binSize );
// perform four normalizations per spatial block
hogChannels( H, R, N, hb, wb, nOrients, clip, 0 );
wrFree(N); wrFree(R);
}
// H=gradHist(M,O,[bin],[nOrients],[softBin],[useHog],[clip])-see gradientHist.m
void mGradHist( int nl, mxArray *pl[], int nr, const mxArray *pr[] ) {
int h, w, d, hb, wb, bin, nOrients; bool softBin, useHog;
float *M, *O, *H, *G, clip;
checkArgs(nl,pl,nr,pr,1,3,2,7,&h,&w,&d,mxSINGLE_CLASS,(void**)&M);
O = (float*) mxGetPr(pr[1]);
if( mxGetM(pr[1])!=h || mxGetN(pr[1])!=w || d!=1 ||
mxGetClassID(pr[1])!=mxSINGLE_CLASS ) mexErrMsgTxt("M or O is bad.");
bin = (nr>=3) ? (int) mxGetScalar(pr[2]) : 8;
nOrients = (nr>=4) ? (int) mxGetScalar(pr[3]) : 9;
softBin = (nr>=5) ? (bool) (mxGetScalar(pr[4])>0) : true;
useHog = (nr>=6) ? (bool) (mxGetScalar(pr[5])>0) : false;
clip = (nr>=7) ? (float) mxGetScalar(pr[6]) : 0.2f;
hb=h/bin; wb=w/bin;
if( useHog==false ) {
pl[0] = mxCreateMatrix3(hb,wb,nOrients,mxSINGLE_CLASS,1,(void**)&H);
gradHist( M, O, H, h, w, bin, nOrients, softBin );
} else {
pl[0] = mxCreateMatrix3(hb,wb,nOrients*4,mxSINGLE_CLASS,1,(void**)&G);
H = (float*) mxCalloc(wb*hb*nOrients,sizeof(float));
gradHist( M, O, H, h, w, bin, nOrients, softBin );
hog( H, G, h, w, bin, nOrients, clip ); mxFree(H);
}
}
/* H = hog( I, [sBin], [oBin] ) - see hog.m */
void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[] ) {
int h, w, d, hb, wb, nb, hb1, wb1, sBin, oBin;
double *I, *M, *H, *HG; float *O;
checkArgs(nlhs,plhs,nrhs,prhs,1,1,1,3,&h,&w,&d,&I);
sBin = (nrhs>=2) ? (int) mxGetScalar(prhs[1]) : 8;
oBin = (nrhs>=3) ? (int) mxGetScalar(prhs[2]) : 9;
hb=h/sBin; wb=w/sBin; nb=wb*hb; hb1=hb>2?hb-2:0; wb1=wb>2?wb-2:0;
plhs[0] = mxCreateMatrix3( hb1, wb1, oBin*4, mxDOUBLE_CLASS, 0, (void**) &HG);
if( hb1==0 || wb1==0 ) return;
M = (double*) mxMalloc(h*w*sizeof(double));
O = (float*) mxMalloc(h*w*sizeof(float));
H = (double*) mxCalloc(nb*oBin, sizeof(double));
gradMag( I, M, O, h, w, d );
gradHist( M, O, H, h, w, d, sBin, oBin, true, true );
hog( H, HG, h, w, d, sBin, oBin );
mxFree(M); mxFree(O); mxFree(H);
}
// compute FHOG features
void fhog( float *M, float *O, float *H, int h, int w, int binSize,
int nOrients, int softBin, float clip )
{
const int hb=h/binSize, wb=w/binSize, nb=hb*wb, nbo=nb*nOrients;
float *N, *R1, *R2; int o, x;
// compute unnormalized constrast sensitive histograms
R1 = (float*) wrCalloc(wb*hb*nOrients*2,sizeof(float));
gradHist( M, O, R1, h, w, binSize, nOrients*2, softBin, true );
// compute unnormalized contrast insensitive histograms
R2 = (float*) wrCalloc(wb*hb*nOrients,sizeof(float));
for( o=0; o<nOrients; o++ ) for( x=0; x<nb; x++ )
R2[o*nb+x] = R1[o*nb+x]+R1[(o+nOrients)*nb+x];
// compute block normalization values
N = hogNormMatrix( R2, nOrients, hb, wb, binSize );
// normalized histograms and texture channels
hogChannels( H+nbo*0, R1, N, hb, wb, nOrients*2, clip, 1 );
hogChannels( H+nbo*2, R2, N, hb, wb, nOrients*1, clip, 1 );
hogChannels( H+nbo*3, R1, N, hb, wb, nOrients*2, clip, 2 );
wrFree(N); mxFree(R1); wrFree(R2);
}