(转)Opencv卷积操作

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Mat kern = (Mat_<char>(3,3) <<  0, -1,  0,

                               -1,  5, -1,

                                0, -1,  0);</char>

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void filter2D(InputArray src, //要进行滤波的图像

              OutputArray dst,//滤波后的图像

              int ddepth,     //原图像的深度  src.depth()

              InputArray kernel, //第一步建立的Mask

              Point anchor=Point(-1,-1),//Mask的中心点

              double delta=0, //Optional value added to the filtered pixels before storing them in dst

              int borderType=BORDER_DEFAULT

               )

filter2D(I, K, I.depth(), kern );

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#include <opencv2 core="" core.hpp="">

#include <opencv2 highgui="" highgui.hpp="">

#include <opencv2 imgproc="" imgproc.hpp="">

#include <iostream>

using namespace std;

using namespace cv;

void help(char* progName)

{

    cout << endl

        <<  "This program shows how to filter images with mask: the write it yourself and the"

        << "filter2d way. " << endl

        <<  "Usage:"                                                                        << endl

        << progName << " [image_name -- default lena.jpg] [G -- grayscale] "        << endl << endl;

}

void Sharpen(const Mat& myImage,Mat& Result);

int main( int argc, char* argv[])

{

    help(argv[0]);

    const char* filename = argc >=2 ? argv[1] : "lena.jpg";

    Mat I, J, K;

    if (argc >= 3 && !strcmp("G", argv[2]))

        I = imread( filename, CV_LOAD_IMAGE_GRAYSCALE);

    else

        I = imread( filename, CV_LOAD_IMAGE_COLOR);

    namedWindow("Input", CV_WINDOW_AUTOSIZE);

    namedWindow("Output", CV_WINDOW_AUTOSIZE);

    imshow("Input", I);

    double t = (double)getTickCount();

    Sharpen(I, J);

    t = ((double)getTickCount() - t)/getTickFrequency();

    cout << "Hand written function times passed in seconds: " << t << endl;

    imshow("Output", J);

    cvWaitKey(0);

    Mat kern = (Mat_<char>(3,3) <<  0, -1,  0,

                                   -1,  5, -1,

                                    0, -1,  0);

    t = (double)getTickCount();

    filter2D(I, K, I.depth(), kern );

    t = ((double)getTickCount() - t)/getTickFrequency();

    cout << "Built-in filter2D time passed in seconds:      " << t << endl;

    imshow("Output", K);

    cvWaitKey(0);

    return 0;

}

void Sharpen(const Mat& myImage,Mat& Result)

{

    CV_Assert(myImage.depth() == CV_8U);  // accept only uchar images

    const int nChannels = myImage.channels();

    Result.create(myImage.size(),myImage.type());

    for(int j = 1 ; j < myImage.rows-1; ++j)

    {

        const uchar* previous = myImage.ptr<uchar>(j - 1);

        const uchar* current  = myImage.ptr<uchar>(j    );

        const uchar* next     = myImage.ptr<uchar>(j + 1);

        uchar* output = Result.ptr<uchar>(j);

        for(int i= nChannels;i < nChannels*(myImage.cols-1); ++i)

        {

            *output++ = saturate_cast<uchar>(5*current[i]

                         -current[i-nChannels] - current[i+nChannels] - previous[i] - next[i]);

        }

    }

    Result.row(0).setTo(Scalar(0));

    Result.row(Result.rows-1).setTo(Scalar(0));

    Result.col(0).setTo(Scalar(0));

    Result.col(Result.cols-1).setTo(Scalar(0));

}</uchar></uchar></uchar></uchar></uchar></char></iostream></opencv2></o