opencv absdiff

opencv中计算两个数组差的绝对值的函数

void cv::absdiff( InputArray src1, InputArray src2, OutputArray dst )
{
    CV_INSTRUMENT_REGION()

    arithm_op(src1, src2, dst, noArray(), -1, getAbsDiffTab(), false, 0, OCL_OP_ABSDIFF);
}

static void arithm_op(InputArray _src1, InputArray _src2, OutputArray _dst,
                      InputArray _mask, int dtype, BinaryFuncC* tab, bool muldiv=false,
                      void* usrdata=0, int oclop=-1 )
{
    const _InputArray *psrc1 = &_src1, *psrc2 = &_src2;
    int kind1 = psrc1->kind(), kind2 = psrc2->kind();
    bool haveMask = !_mask.empty();
    bool reallocate = false;
    int type1 = psrc1->type(), depth1 = CV_MAT_DEPTH(type1), cn = CV_MAT_CN(type1);
    int type2 = psrc2->type(), depth2 = CV_MAT_DEPTH(type2), cn2 = CV_MAT_CN(type2);
    int wtype, dims1 = psrc1->dims(), dims2 = psrc2->dims();
    Size sz1 = dims1 <= 2 ? psrc1->size() : Size();
    Size sz2 = dims2 <= 2 ? psrc2->size() : Size();
#ifdef HAVE_OPENCL
    bool use_opencl = OCL_PERFORMANCE_CHECK(_dst.isUMat()) && dims1 <= 2 && dims2 <= 2;
#endif
    bool src1Scalar = checkScalar(*psrc1, type2, kind1, kind2);
    bool src2Scalar = checkScalar(*psrc2, type1, kind2, kind1);

    if( (kind1 == kind2 || cn == 1) && sz1 == sz2 && dims1 <= 2 && dims2 <= 2 && type1 == type2 &&
        !haveMask && ((!_dst.fixedType() && (dtype < 0 || CV_MAT_DEPTH(dtype) == depth1)) ||
                       (_dst.fixedType() && _dst.type() == type1)) &&
        ((src1Scalar && src2Scalar) || (!src1Scalar && !src2Scalar)) )
    {
        _dst.createSameSize(*psrc1, type1);
        CV_OCL_RUN(use_opencl,
            ocl_arithm_op(*psrc1, *psrc2, _dst, _mask,
                          (!usrdata ? type1 : std::max(depth1, CV_32F)),
                          usrdata, oclop, false))

        Mat src1 = psrc1->getMat(), src2 = psrc2->getMat(), dst = _dst.getMat();
        Size sz = getContinuousSize(src1, src2, dst, src1.channels());
        tab[depth1](src1.ptr(), src1.step, src2.ptr(), src2.step, dst.ptr(), dst.step, sz.width, sz.height, usrdata);
        return;
    }

    bool haveScalar = false, swapped12 = false;

    if( dims1 != dims2 || sz1 != sz2 || cn != cn2 ||
        (kind1 == _InputArray::MATX && (sz1 == Size(1,4) || sz1 == Size(1,1))) ||
        (kind2 == _InputArray::MATX && (sz2 == Size(1,4) || sz2 == Size(1,1))) )
    {
        if( checkScalar(*psrc1, type2, kind1, kind2) )
        {
            // src1 is a scalar; swap it with src2
            swap(psrc1, psrc2);
            swap(sz1, sz2);
            swap(type1, type2);
            swap(depth1, depth2);
            swap(cn, cn2);
            swap(dims1, dims2);
            swapped12 = true;
            if( oclop == OCL_OP_SUB )
                oclop = OCL_OP_RSUB;
            if ( oclop == OCL_OP_DIV_SCALE )
                oclop = OCL_OP_RDIV_SCALE;
        }
        else if( !checkScalar(*psrc2, type1, kind2, kind1) )
            CV_Error( CV_StsUnmatchedSizes,
                     "The operation is neither 'array op array' "
                     "(where arrays have the same size and the same number of channels), "
                     "nor 'array op scalar', nor 'scalar op array'" );
        haveScalar = true;
        CV_Assert(type2 == CV_64F && (sz2.height == 1 || sz2.height == 4));

        if (!muldiv)
        {
            Mat sc = psrc2->getMat();
            depth2 = actualScalarDepth(sc.ptr<double>(), sz2 == Size(1, 1) ? cn2 : cn);
            if( depth2 == CV_64F && (depth1 < CV_32S || depth1 == CV_32F) )
                depth2 = CV_32F;
        }
        else
            depth2 = CV_64F;
    }

    if( dtype < 0 )
    {
        if( _dst.fixedType() )
            dtype = _dst.type();
        else
        {
            if( !haveScalar && type1 != type2 )
                CV_Error(CV_StsBadArg,
                     "When the input arrays in add/subtract/multiply/divide functions have different types, "
                     "the output array type must be explicitly specified");
            dtype = type1;
        }
    }
    dtype = CV_MAT_DEPTH(dtype);

    if( depth1 == depth2 && dtype == depth1 )
        wtype = dtype;
    else if( !muldiv )
    {
        wtype = depth1 <= CV_8S && depth2 <= CV_8S ? CV_16S :
                depth1 <= CV_32S && depth2 <= CV_32S ? CV_32S : std::max(depth1, depth2);
        wtype = std::max(wtype, dtype);

        // when the result of addition should be converted to an integer type,
        // and just one of the input arrays is floating-point, it makes sense to convert that input to integer type before the operation,
        // instead of converting the other input to floating-point and then converting the operation result back to integers.
        if( dtype < CV_32F && (depth1 < CV_32F || depth2 < CV_32F) )
            wtype = CV_32S;
    }
    else
    {
        wtype = std::max(depth1, std::max(depth2, CV_32F));
        wtype = std::max(wtype, dtype);
    }

    dtype = CV_MAKETYPE(dtype, cn);
    wtype = CV_MAKETYPE(wtype, cn);

    if( haveMask )
    {
        int mtype = _mask.type();
        CV_Assert( (mtype == CV_8UC1 || mtype == CV_8SC1) && _mask.sameSize(*psrc1) );
        reallocate = !_dst.sameSize(*psrc1) || _dst.type() != dtype;
    }

    _dst.createSameSize(*psrc1, dtype);
    if( reallocate )
        _dst.setTo(0.);

    CV_OCL_RUN(use_opencl,
               ocl_arithm_op(*psrc1, *psrc2, _dst, _mask, wtype,
               usrdata, oclop, haveScalar))

    BinaryFunc cvtsrc1 = type1 == wtype ? 0 : getConvertFunc(type1, wtype);
    BinaryFunc cvtsrc2 = type2 == type1 ? cvtsrc1 : type2 == wtype ? 0 : getConvertFunc(type2, wtype);
    BinaryFunc cvtdst = dtype == wtype ? 0 : getConvertFunc(wtype, dtype);

    size_t esz1 = CV_ELEM_SIZE(type1), esz2 = CV_ELEM_SIZE(type2);
    size_t dsz = CV_ELEM_SIZE(dtype), wsz = CV_ELEM_SIZE(wtype);
    size_t blocksize0 = (size_t)(BLOCK_SIZE + wsz-1)/wsz;
    BinaryFunc copymask = getCopyMaskFunc(dsz);
    Mat src1 = psrc1->getMat(), src2 = psrc2->getMat(), dst = _dst.getMat(), mask = _mask.getMat();

    AutoBuffer<uchar> _buf;
    uchar *buf, *maskbuf = 0, *buf1 = 0, *buf2 = 0, *wbuf = 0;
    size_t bufesz = (cvtsrc1 ? wsz : 0) +
                    (cvtsrc2 || haveScalar ? wsz : 0) +
                    (cvtdst ? wsz : 0) +
                    (haveMask ? dsz : 0);
    BinaryFuncC func = tab[CV_MAT_DEPTH(wtype)];

    if( !haveScalar )
    {
        const Mat* arrays[] = { &src1, &src2, &dst, &mask, 0 };
        uchar* ptrs[4];

        NAryMatIterator it(arrays, ptrs);
        size_t total = it.size, blocksize = total;

        if( haveMask || cvtsrc1 || cvtsrc2 || cvtdst )
            blocksize = std::min(blocksize, blocksize0);

        _buf.allocate(bufesz*blocksize + 64);
        buf = _buf;
        if( cvtsrc1 )
            buf1 = buf, buf = alignPtr(buf + blocksize*wsz, 16);
        if( cvtsrc2 )
            buf2 = buf, buf = alignPtr(buf + blocksize*wsz, 16);
        wbuf = maskbuf = buf;
        if( cvtdst )
            buf = alignPtr(buf + blocksize*wsz, 16);
        if( haveMask )
            maskbuf = buf;

        for( size_t i = 0; i < it.nplanes; i++, ++it )
        {
            for( size_t j = 0; j < total; j += blocksize )
            {
                int bsz = (int)MIN(total - j, blocksize);
                Size bszn(bsz*cn, 1);
                const uchar *sptr1 = ptrs[0], *sptr2 = ptrs[1];
                uchar* dptr = ptrs[2];
                if( cvtsrc1 )
                {
                    cvtsrc1( sptr1, 1, 0, 1, buf1, 1, bszn, 0 );
                    sptr1 = buf1;
                }
                if( ptrs[0] == ptrs[1] )
                    sptr2 = sptr1;
                else if( cvtsrc2 )
                {
                    cvtsrc2( sptr2, 1, 0, 1, buf2, 1, bszn, 0 );
                    sptr2 = buf2;
                }

                if( !haveMask && !cvtdst )
                    func( sptr1, 1, sptr2, 1, dptr, 1, bszn.width, bszn.height, usrdata );
                else
                {
                    func( sptr1, 1, sptr2, 1, wbuf, 0, bszn.width, bszn.height, usrdata );
                    if( !haveMask )
                        cvtdst( wbuf, 1, 0, 1, dptr, 1, bszn, 0 );
                    else if( !cvtdst )
                    {
                        copymask( wbuf, 1, ptrs[3], 1, dptr, 1, Size(bsz, 1), &dsz );
                        ptrs[3] += bsz;
                    }
                    else
                    {
                        cvtdst( wbuf, 1, 0, 1, maskbuf, 1, bszn, 0 );
                        copymask( maskbuf, 1, ptrs[3], 1, dptr, 1, Size(bsz, 1), &dsz );
                        ptrs[3] += bsz;
                    }
                }
                ptrs[0] += bsz*esz1; ptrs[1] += bsz*esz2; ptrs[2] += bsz*dsz;
            }
        }
    }
    else
    {
        const Mat* arrays[] = { &src1, &dst, &mask, 0 };
        uchar* ptrs[3];

        NAryMatIterator it(arrays, ptrs);
        size_t total = it.size, blocksize = std::min(total, blocksize0);

        _buf.allocate(bufesz*blocksize + 64);
        buf = _buf;
        if( cvtsrc1 )
            buf1 = buf, buf = alignPtr(buf + blocksize*wsz, 16);
        buf2 = buf; buf = alignPtr(buf + blocksize*wsz, 16);
        wbuf = maskbuf = buf;
        if( cvtdst )
            buf = alignPtr(buf + blocksize*wsz, 16);
        if( haveMask )
            maskbuf = buf;

        convertAndUnrollScalar( src2, wtype, buf2, blocksize);

        for( size_t i = 0; i < it.nplanes; i++, ++it )
        {
            for( size_t j = 0; j < total; j += blocksize )
            {
                int bsz = (int)MIN(total - j, blocksize);
                Size bszn(bsz*cn, 1);
                const uchar *sptr1 = ptrs[0];
                const uchar* sptr2 = buf2;
                uchar* dptr = ptrs[1];

                if( cvtsrc1 )
                {
                    cvtsrc1( sptr1, 1, 0, 1, buf1, 1, bszn, 0 );
                    sptr1 = buf1;
                }

                if( swapped12 )
                    std::swap(sptr1, sptr2);

                if( !haveMask && !cvtdst )
                    func( sptr1, 1, sptr2, 1, dptr, 1, bszn.width, bszn.height, usrdata );
                else
                {
                    func( sptr1, 1, sptr2, 1, wbuf, 1, bszn.width, bszn.height, usrdata );
                    if( !haveMask )
                        cvtdst( wbuf, 1, 0, 1, dptr, 1, bszn, 0 );
                    else if( !cvtdst )
                    {
                        copymask( wbuf, 1, ptrs[2], 1, dptr, 1, Size(bsz, 1), &dsz );
                        ptrs[2] += bsz;
                    }
                    else
                    {
                        cvtdst( wbuf, 1, 0, 1, maskbuf, 1, bszn, 0 );
                        copymask( maskbuf, 1, ptrs[2], 1, dptr, 1, Size(bsz, 1), &dsz );
                        ptrs[2] += bsz;
                    }
                }
                ptrs[0] += bsz*esz1; ptrs[1] += bsz*dsz;
            }
        }
    }
}

代码来自：opencv3_4_1opencv-3.4.1modulescoresrcarithm.cpp  990

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