opencv  calcHist1D_Invoker

 

template<typename T>
class calcHist1D_Invoker
{
public:
    calcHist1D_Invoker( const std::vector<uchar*>& _ptrs, const std::vector<int>& _deltas,
                        Mat& hist, const double* _uniranges, int sz, int dims,
                        Size& imageSize )
        : mask_(_ptrs[dims]),
          mstep_(_deltas[dims*2 + 1]),
          imageWidth_(imageSize.width),
          histogramSize_(hist.size()), histogramType_(hist.type()),
          globalHistogram_((tbb::atomic<int>*)hist.data)
    {
        p_[0] = ((T**)&_ptrs[0])[0];
        step_[0] = (&_deltas[0])[1];
        d_[0] = (&_deltas[0])[0];
        a_[0] = (&_uniranges[0])[0];
        b_[0] = (&_uniranges[0])[1];
        size_[0] = sz;
    }

    void operator()( const BlockedRange& range ) const
    {
        T* p0 = p_[0] + range.begin() * (step_[0] + imageWidth_*d_[0]);
        uchar* mask = mask_ + range.begin()*mstep_;

        for( int row = range.begin(); row < range.end(); row++, p0 += step_[0] )
        {
            if( !mask_ )
            {
                for( int x = 0; x < imageWidth_; x++, p0 += d_[0] )
                {
                    int idx = cvFloor(*p0*a_[0] + b_[0]);
                    if( (unsigned)idx < (unsigned)size_[0] )
                    {
                        globalHistogram_[idx].fetch_and_add(1);
                    }
                }
            }
            else
            {
                for( int x = 0; x < imageWidth_; x++, p0 += d_[0] )
                {
                    if( mask[x] )
                    {
                        int idx = cvFloor(*p0*a_[0] + b_[0]);
                        if( (unsigned)idx < (unsigned)size_[0] )
                        {
                            globalHistogram_[idx].fetch_and_add(1);
                        }
                    }
                }
                mask += mstep_;
            }
        }
    }

private:
    calcHist1D_Invoker operator=(const calcHist1D_Invoker&);

    T* p_[one];
    uchar* mask_;
    int step_[one];
    int d_[one];
    int mstep_;
    double a_[one];
    double b_[one];
    int size_[one];
    int imageWidth_;
    Size histogramSize_;
    int histogramType_;
    tbb::atomic<int>* globalHistogram_;
};

 

 

 

代码参考：opencv-3.4.1\modules\imgproc\src\histogram.cpp

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