opencv calcHist3D_Invoker

opencv  calcHist3D_Invoker

template<typename T>
class calcHist3D_Invoker
{
public:
    calcHist3D_Invoker( const std::vector<uchar*>& _ptrs, const std::vector<int>& _deltas,
                        Size imsize, Mat& hist, const double* uniranges, int _dims,
                        size_t* hstep, int* size )
        : mask_(_ptrs[_dims]),
          mstep_(_deltas[_dims*2 + 1]),
          imageWidth_(imsize.width),
          globalHistogram_(hist.data)
    {
        p_[0] = ((T**)&_ptrs[0])[0]; p_[1] = ((T**)&_ptrs[0])[1]; p_[2] = ((T**)&_ptrs[0])[2];
        step_[0] = (&_deltas[0])[1]; step_[1] = (&_deltas[0])[3]; step_[2] = (&_deltas[0])[5];
        d_[0] = (&_deltas[0])[0];    d_[1] = (&_deltas[0])[2];    d_[2] = (&_deltas[0])[4];
        a_[0] = uniranges[0];        a_[1] = uniranges[2];        a_[2] = uniranges[4];
        b_[0] = uniranges[1];        b_[1] = uniranges[3];        b_[2] = uniranges[5];
        size_[0] = size[0];          size_[1] = size[1];          size_[2] = size[2];
        hstep_[0] = hstep[0];        hstep_[1] = hstep[1];
    }

    void operator()( const BlockedRange& range ) const
    {
        T* p0 = p_[0] + range.begin()*(imageWidth_*d_[0] + step_[0]);
        T* p1 = p_[1] + range.begin()*(imageWidth_*d_[1] + step_[1]);
        T* p2 = p_[2] + range.begin()*(imageWidth_*d_[2] + step_[2]);
        uchar* mask = mask_ + range.begin()*mstep_;

        for( int i = range.begin(); i < range.end(); i++, p0 += step_[0], p1 += step_[1], p2 += step_[2] )
        {
            if( !mask_ )
            {
                for( int x = 0; x < imageWidth_; x++, p0 += d_[0], p1 += d_[1], p2 += d_[2] )
                {
                    int idx0 = cvFloor(*p0*a_[0] + b_[0]);
                    int idx1 = cvFloor(*p1*a_[1] + b_[1]);
                    int idx2 = cvFloor(*p2*a_[2] + b_[2]);
                    if( (unsigned)idx0 < (unsigned)size_[0] &&
                            (unsigned)idx1 < (unsigned)size_[1] &&
                            (unsigned)idx2 < (unsigned)size_[2] )
                    {
                        ( (tbb::atomic<int>*)(globalHistogram_ + hstep_[0]*idx0 + hstep_[1]*idx1) )[idx2].fetch_and_add(1);
                    }
                }
            }
            else
            {
                for( int x = 0; x < imageWidth_; x++, p0 += d_[0], p1 += d_[1], p2 += d_[2] )
                {
                    if( mask[x] )
                    {
                        int idx0 = cvFloor(*p0*a_[0] + b_[0]);
                        int idx1 = cvFloor(*p1*a_[1] + b_[1]);
                        int idx2 = cvFloor(*p2*a_[2] + b_[2]);
                        if( (unsigned)idx0 < (unsigned)size_[0] &&
                                (unsigned)idx1 < (unsigned)size_[1] &&
                                (unsigned)idx2 < (unsigned)size_[2] )
                        {
                            ( (tbb::atomic<int>*)(globalHistogram_ + hstep_[0]*idx0 + hstep_[1]*idx1) )[idx2].fetch_and_add(1);
                        }
                    }
                }
                mask += mstep_;
            }
        }
    }

    static bool isFit( const Mat& histogram, const Size imageSize )
    {
        return ( imageSize.width * imageSize.height >= 320*240
                 && histogram.total() >= 8*8*8 );
    }

private:
    calcHist3D_Invoker operator=(const calcHist3D_Invoker&);

    T* p_[three];
    uchar* mask_;
    int step_[three];
    int d_[three];
    const int mstep_;
    double a_[three];
    double b_[three];
    int size_[three];
    int imageWidth_;
    size_t hstep_[two];
    uchar* globalHistogram_;
};

代码参考：opencv-3.4.1modulesimgprocsrchistogram.cpp

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