【OpenCV】使用floodfill()实现PhotoShop魔棒功能

在OpenCV中看到一个很有意思的函数：floodfill()

使用给定颜色填充一个联通的区域

 C++: int floodFill(InputOutputArray image, Point seedPoint,
 Scalar newVal, Rect* rect=0, Scalar loDiff=Scalar(),
 Scalar upDiff=Scalar(), int flags=4 )

一个简单的例子：

 #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( )
 {
     char* filename="0.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;
 }

点击图标改变图像中的连图区域的颜色：

转载 ：http://blog.csdn.net/xiaowei_cqu/article/details/8987387