使用floodfill()函数:

#include "opencv2/imgproc/imgproc.hpp"

#include "opencv2/highgui/highgui.hpp"

#include <iostream>

using namespace cv;

using namespace std;

//floodfill()

//Fills a connected component with the given color.

static void help()

{

    cout << "\nThis program demonstrated the floodFill() function\n"

        "Call:\n"

        "./ffilldemo [image_name -- Default: fruits.jpg]\n" << endl;

    cout << "Hot keys: \n"

        "\tESC - quit the program\n"

        "\tc - switch color/grayscale mode\n"

        "\tm - switch mask mode\n"

        "\tr - restore the original image\n"

        "\ts - use null-range floodfill\n"

        "\tf - use gradient floodfill with fixed(absolute) range\n"

        "\tg - use gradient floodfill with floating(relative) range\n"

        "\t4 - use 4-connectivity mode\n"

        "\t8 - use 8-connectivity mode\n" << endl;

}

Mat image0, image, gray, mask;

int ffillMode = 1;

int loDiff = 20, upDiff = 20;

int connectivity = 4;

int isColor = true;

bool useMask = false;

int newMaskVal = 255;

static void onMouse( int event, int x, int y, int, void* )

{

    if( event != CV_EVENT_LBUTTONDOWN )

        return;

    Point seed = Point(x,y);

    int lo = ffillMode == 0 ? 0 : loDiff;

    int up = ffillMode == 0 ? 0 : upDiff;

    int flags = connectivity + (newMaskVal << 8) +

        (ffillMode == 1 ? CV_FLOODFILL_FIXED_RANGE : 0);

    int b = (unsigned)theRNG() & 255;

    int g = (unsigned)theRNG() & 255;

    int r = (unsigned)theRNG() & 255;

    Rect ccomp;

    Scalar newVal = isColor ? Scalar(b, g, r) : Scalar(r*0.299 + g*0.587 + b*0.114);

    Mat dst = isColor ? image : gray;

    int area;

    if( useMask )

    {

        threshold(mask, mask, 1, 128, CV_THRESH_BINARY);

        area = floodFill(dst, mask, seed, newVal, &ccomp, Scalar(lo, lo, lo),

            Scalar(up, up, up), flags);

        imshow( "mask", mask );

    }

    else

    {

        area = floodFill(dst, seed, newVal, &ccomp, Scalar(lo, lo, lo),

            Scalar(up, up, up), flags);

    }

    imshow("image", dst);

    cout << area << " pixels were repainted\n";

}

int main( int argc, char** argv )

{

    char* filename= argc >= 2 ? argv[1] : (char*)"pic5.png";

    image0 = imread(filename, 1);

    if( image0.empty() )

    {

        cout << "Image empty. Usage: ffilldemo <image_name>\n";

        return 0;

    }

    help();

    image0.copyTo(image);

    cvtColor(image0, gray, CV_BGR2GRAY);

    mask.create(image0.rows+2, image0.cols+2, CV_8UC1);

    namedWindow( "image", 0 );

    createTrackbar( "lo_diff", "image", &loDiff, 255, 0 );

    createTrackbar( "up_diff", "image", &upDiff, 255, 0 );

    setMouseCallback( "image", onMouse, 0 );

    for(;;)

    {

        imshow("image", isColor ? image : gray);

        int c = waitKey(0);

        if( (c & 255) == 27 )

        {

            cout << "Exiting ...\n";

            break;

        }

        switch( (char)c )

        {

        case 'c':

            if( isColor )

            {

                cout << "Grayscale mode is set\n";

                cvtColor(image0, gray, CV_BGR2GRAY);

                mask = Scalar::all(0);

                isColor = false;

            }

            else

            {

                cout << "Color mode is set\n";

                image0.copyTo(image);

                mask = Scalar::all(0);

                isColor = true;

            }

            break;

        case 'm':

            if( useMask )

            {

                destroyWindow( "mask" );

                useMask = false;

            }

            else

            {

                namedWindow( "mask", 0 );

                mask = Scalar::all(0);

                imshow("mask", mask);

                useMask = true;

            }

            break;

        case 'r':

            cout << "Original image is restored\n";

            image0.copyTo(image);

            cvtColor(image, gray, CV_BGR2GRAY);

            mask = Scalar::all(0);

            break;

        case 's':

            cout << "Simple floodfill mode is set\n";

            ffillMode = 0;

            break;

        case 'f':

            cout << "Fixed Range floodfill mode is set\n";

            ffillMode = 1;

            break;

        case 'g':

            cout << "Gradient (floating range) floodfill mode is set\n";

            ffillMode = 2;

            break;

        case '4':

            cout << "4-connectivity mode is set\n";

            connectivity = 4;

            break;

        case '8':

            cout << "8-connectivity mode is set\n";

            connectivity = 8;

            break;

        }

    }

    return 0;

}