float Histogram::compareHist(Histogram h2,int method=comparison_method::NORM_L1)
{
Mat H1=this->getHist();
Mat H2=h2.getHist();
const Mat* arrays[] = {&H1, &H2, 0};
// H1.t()
// cv::pyrDown()
//planes,number of channels of histogram
Mat planes[2];
//N Dimensional array iterator
NAryMatIterator it(arrays, planes);
int len = it.planes[0].rows*it.planes[0].cols;
float result=0;
float a=0,b=0,s1=0,s2=0;
float s11=0,s12=0,s22=0;
//cerr << it.nplanes << endl;
//cerr << it.planes[0].rows << ":" << it.planes[0].cols << endl;
for( size_t i = 0; i < it.nplanes; i++, ++it )
{
const float* h1 = (const float*)it.planes[0].data;
const float* h2 = (const float*)it.planes[1].data;
if(method==comparison_method::NORM_L1)
{
for( int j = 0; j < len; j++ )
{
double a = abs(h1[j] - h2[j]);
if( fabs(a) > DBL_EPSILON )
result += a;
}
result=result/len;
}
else if(method==comparison_method::NORM_L2)
{
for( int j = 0; j < len; j++ )
{
double a = (h1[j] - h2[j])*(h1[j] - h2[j]);
if( fabs(a) > DBL_EPSILON )
result += a;
}
result=result/len;
}
else if(method == comparison_method::CHI_SQUARED)
{
for( int j = 0; j < len; j++ )
{
double a = h1[j] - h2[j];
double b = h1[j];
if( fabs(b) > DBL_EPSILON )
result += a*a/b;
}
}
else if( method == comparison_method::INTERSECTION )
{
for( int j = 0; j < len; j++ )
result += std::min(h1[j], h2[j]);
}
else if( method == comparison_method::BHATTACHRYA || method == comparison_method::BHATTACHRYA1 )
{
for( int j = 0; j < len; j++ )
{
double a = h1[j];
double b = h2[j];
result += std::sqrt(a*b);
s1 += a;
s2 += b;
}
cerr << (float)s1 <<":" << (float)s2 << endl;
}
else if( method == comparison_method::CORRELATION )
{
for( int j = 0; j < len; j++ )
{
double a = h1[j];
double b = h2[j];
s12 += a*b;
s1 += a;
s11 += a*a;
s2 += b;
s22 += b*b;
}
}
else
{
CV_Error( CV_StsBadArg, "Unknown comparison method" );
}
}
if(method==comparison_method::CORRELATION)
{
s1=s1/len;
s2=s2/len;
size_t total = len;
double scale = 1./total;
double num = s12 -(total*s1*s2);
double denom2 = (s11 - s1*s1*total)*(s22 - s2*s2*total);
result = std::abs(denom2) > DBL_EPSILON ? num/std::sqrt(denom2) : 1.;
}
else if( method == comparison_method::BHATTACHRYA|| method == comparison_method::BHATTACHRYA1)
{
s1 *= s2;
s1 = fabs(s1) > FLT_EPSILON ? 1./std::sqrt(s1) : 1.;
if( method == comparison_method::BHATTACHRYA1)
result=result*s1;
else
result = std::sqrt(std::max(1. - result*s1, 0.));
}
return result;
}
