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

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 \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：?

--------------------------------------分割线 --------------------------------------

--------------------------------------分割线 --------------------------------------