双边滤波OpenCV源码

1、源码路径

OpenCV\modules\opencv_imgproc\Src\bilateral_filter.dispatch.cpp


2、源码代码

void bilateralFilter( InputArray _src, OutputArray _dst, int d,double sigmaColor, double sigmaSpace,int borderType )
{CV_INSTRUMENT_REGION();CV_Assert(!_src.empty());_dst.create( _src.size(), _src.type() );CV_OCL_RUN(_src.dims() <&＃61; 2 && _dst.isUMat(),ocl_bilateralFilter_8u(_src, _dst, d, sigmaColor, sigmaSpace, borderType))Mat src &＃61; _src.getMat(), dst &＃61; _dst.getMat();CV_IPP_RUN_FAST(ipp_bilateralFilter(src, dst, d, sigmaColor, sigmaSpace, borderType));if( src.depth() &＃61;&＃61; CV_8U )bilateralFilter_8u( src, dst, d, sigmaColor, sigmaSpace, borderType );else if( src.depth() &＃61;&＃61; CV_32F )bilateralFilter_32f( src, dst, d, sigmaColor, sigmaSpace, borderType );elseCV_Error( CV_StsUnsupportedFormat,"Bilateral filtering is only implemented for 8u and 32f images" );
}

static void
bilateralFilter_32f( const Mat& src, Mat& dst, int d,double sigma_color, double sigma_space,int borderType )
{CV_INSTRUMENT_REGION();int cn &＃61; src.channels();int i, j, maxk, radius;double minValSrc&＃61;-1, maxValSrc&＃61;1;const int kExpNumBinsPerChannel &＃61; 1 << 12;int kExpNumBins &＃61; 0;float lastExpVal &＃61; 1.f;float len, scale_index;CV_Assert( (src.type() &＃61;&＃61; CV_32FC1 || src.type() &＃61;&＃61; CV_32FC3) && src.data !&＃61; dst.data );if( sigma_color <&＃61; 0 )sigma_color &＃61; 1;if( sigma_space <&＃61; 0 )sigma_space &＃61; 1;double gauss_color_coeff &＃61; -0.5/(sigma_color*sigma_color);double gauss_space_coeff &＃61; -0.5/(sigma_space*sigma_space);if( d <&＃61; 0 )radius &＃61; cvRound(sigma_space*1.5);elseradius &＃61; d/2;radius &＃61; MAX(radius, 1);d &＃61; radius*2 &＃43; 1;// compute the min/max range for the input image (even if multichannel)minMaxLoc( src.reshape(1), &minValSrc, &maxValSrc );if(std::abs(minValSrc - maxValSrc) < FLT_EPSILON){src.copyTo(dst);return;}// temporary copy of the image with borders for easy processingMat temp;copyMakeBorder( src, temp, radius, radius, radius, radius, borderType );// allocate lookup tablesstd::vector<float> _space_weight(d*d);std::vector<int> _space_ofs(d*d);float* space_weight &＃61; &_space_weight[0];int* space_ofs &＃61; &_space_ofs[0];// assign a length which is slightly more than neededlen &＃61; (float)(maxValSrc - minValSrc) * cn;kExpNumBins &＃61; kExpNumBinsPerChannel * cn;std::vector<float> _expLUT(kExpNumBins&＃43;2);float* expLUT &＃61; &_expLUT[0];scale_index &＃61; kExpNumBins/len;// initialize the exp LUTfor( i &＃61; 0; i < kExpNumBins&＃43;2; i&＃43;&＃43; ){if( lastExpVal > 0.f ){double val &＃61; i / scale_index;expLUT[i] &＃61; (float)std::exp(val * val * gauss_color_coeff);lastExpVal &＃61; expLUT[i];}elseexpLUT[i] &＃61; 0.f;}// initialize space-related bilateral filter coefficientsfor( i &＃61; -radius, maxk &＃61; 0; i <&＃61; radius; i&＃43;&＃43; )for( j &＃61; -radius; j <&＃61; radius; j&＃43;&＃43; ){double r &＃61; std::sqrt((double)i*i &＃43; (double)j*j);if( r > radius || ( i &＃61;&＃61; 0 && j &＃61;&＃61; 0 ) )continue;space_weight[maxk] &＃61; (float)std::exp(r*r*gauss_space_coeff);space_ofs[maxk&＃43;&＃43;] &＃61; (int)(i*(temp.step/sizeof(float)) &＃43; j*cn);}// parallel_for usageCV_CPU_DISPATCH(bilateralFilterInvoker_32f, (cn, radius, maxk, space_ofs, temp, dst, scale_index, space_weight, expLUT),CV_CPU_DISPATCH_MODES_ALL);
}


static void
bilateralFilter_8u( const Mat& src, Mat& dst, int d,double sigma_color, double sigma_space,int borderType )
{CV_INSTRUMENT_REGION();int cn &＃61; src.channels();int i, j, maxk, radius;CV_Assert( (src.type() &＃61;&＃61; CV_8UC1 || src.type() &＃61;&＃61; CV_8UC3) && src.data !&＃61; dst.data );if( sigma_color <&＃61; 0 )sigma_color &＃61; 1;if( sigma_space <&＃61; 0 )sigma_space &＃61; 1;double gauss_color_coeff &＃61; -0.5/(sigma_color*sigma_color);double gauss_space_coeff &＃61; -0.5/(sigma_space*sigma_space);if( d <&＃61; 0 )radius &＃61; cvRound(sigma_space*1.5);elseradius &＃61; d/2;radius &＃61; MAX(radius, 1);d &＃61; radius*2 &＃43; 1;Mat temp;copyMakeBorder( src, temp, radius, radius, radius, radius, borderType );std::vector<float> _color_weight(cn*256);std::vector<float> _space_weight(d*d);std::vector<int> _space_ofs(d*d);float* color_weight &＃61; &_color_weight[0];float* space_weight &＃61; &_space_weight[0];int* space_ofs &＃61; &_space_ofs[0];// initialize color-related bilateral filter coefficientsfor( i &＃61; 0; i < 256*cn; i&＃43;&＃43; )color_weight[i] &＃61; (float)std::exp(i*i*gauss_color_coeff);// initialize space-related bilateral filter coefficientsfor( i &＃61; -radius, maxk &＃61; 0; i <&＃61; radius; i&＃43;&＃43; ){j &＃61; -radius;for( ; j <&＃61; radius; j&＃43;&＃43; ){double r &＃61; std::sqrt((double)i*i &＃43; (double)j*j);if( r > radius )continue;space_weight[maxk] &＃61; (float)std::exp(r*r*gauss_space_coeff);space_ofs[maxk&＃43;&＃43;] &＃61; (int)(i*temp.step &＃43; j*cn);}}CV_CPU_DISPATCH(bilateralFilterInvoker_8u, (dst, temp, radius, maxk, space_ofs, space_weight, color_weight),CV_CPU_DISPATCH_MODES_ALL);
}