Function cvNormalizeHist

deps/opencv/modules/imgproc/src/histogram.cpp:2289–2329

Normalizes histogram (make sum of the histogram bins == factor)

// Normalizes histogram (make sum of the histogram bins == factor)
CV_IMPL void
cvNormalizeHist( CvHistogram* hist, double factor )
{
    double sum = 0;

    if( !CV_IS_HIST(hist) )
        CV_Error( CV_StsBadArg, "Invalid histogram header" );

    if( !CV_IS_SPARSE_HIST(hist) )
    {
        CvMat mat;
        cvGetMat( hist->bins, &mat, 0, 1 );
        sum = cvSum( &mat ).val[0];
        if( fabs(sum) < DBL_EPSILON )
            sum = 1;
        cvScale( &mat, &mat, factor/sum, 0 );
    }
    else
    {
        CvSparseMat* mat = (CvSparseMat*)hist->bins;
        CvSparseMatIterator iterator;
        CvSparseNode *node;
        float scale;

        for( node = cvInitSparseMatIterator( mat, &iterator );
             node != 0; node = cvGetNextSparseNode( &iterator ))
        {
            sum += *(float*)CV_NODE_VAL(mat,node);
        }

        if( fabs(sum) < DBL_EPSILON )
            sum = 1;
        scale = (float)(factor/sum);

        for( node = cvInitSparseMatIterator( mat, &iterator );
             node != 0; node = cvGetNextSparseNode( &iterator ))
        {
            *(float*)CV_NODE_VAL(mat,node) *= scale;
        }
    }
}


// Retrieves histogram global min, max and their positions