示例/cpp/connected_components.cpp

该程序演示了连通组件的使用以及滑块的使用

 
#include <opencv2/core/utility.hpp>
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>
 
using namespace cv;
using namespace std;
 
Mat img;
int threshval = 100;
 
static void on_trackbar(int, void*)
{
    Mat bw = threshval < 128 ? (img < threshval) : (img > threshval);
    Mat labelImage(img.size(), CV_32S);
    int nLabels = connectedComponents(bw, labelImage, 8);
std::vector<Vec3b> colors(nLabels);
colors[0] = Vec3b(0, 0, 0);//背景
    for(int label = 1; label < nLabels; ++label){
colors[label] = Vec3b( (rand()&255), (rand()&255), (rand()&255) );
    }
    Mat dst(img.size(), CV_8UC3);
    for(int r = 0; r < dst.rows; ++r){
        for(int c = 0; c < dst.cols; ++c){
            int label = labelImage.at<int>(r, c);
            Vec3b &pixel = dst.at<Vec3b>(r, c);
pixel = colors[label];
         }
     }
 
imshow( "Connected Components", dst );
}
 
int main( int argc, const char** argv )
{
    CommandLineParser parser(argc, argv, "{@image|stuff.jpg|图像用于转换为灰度图}");
parser.about("\n该程序演示了连通组件的使用以及滑块的使用\n");
parser.printMessage();
cout << "\n图像被转换为灰度并显示，另一个图像有一个滑块\n"
            "控制阈值，从而提取以颜色绘制的轮廓\n";
 
    String inputImage = parser.get<string>(0);
img = imread(samples::findFile(inputImage), IMREAD_GRAYSCALE);
 
    if(img.empty())
    {
cout << "无法读取输入图像文件：" << inputImage << endl;
        return EXIT_FAILURE;
    }
 
    imshow( "Image", img );
 
    namedWindow( "Connected Components", WINDOW_AUTOSIZE);
    createTrackbar( "Threshold", "Connected Components", &threshval, 255, on_trackbar );
on_trackbar(threshval, 0);
 
    waitKey(0);
    return EXIT_SUCCESS;
}