识别圈子

Question

下面给出的代码用于识别视频Feed中的圈子。 for循环没有执行。为什么会这样？

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <opencv/cv.h>
#include <iostream>
#include <stdio.h>

using namespace cv;

int main(int argc, char** argv)
{
    CvCapture* capture=0;
    capture=cvCaptureFromCAM(0);
    if(!capture)
    {
        printf("Capture failure\n");
        return -1;
    }
    IplImage* frame;
    while(true)
    {
        frame=cvQueryFrame(capture);
        if(!frame) break;
        Mat src(frame);
        IplImage* framegray=cvCreateImage(cvGetSize(frame),8,3);
        Mat srcgray(framegray);
        cvtColor(src,srcgray,CV_BGR2GRAY);
        GaussianBlur(srcgray,srcgray,Size(9, 9), 2, 2 );
        vector<Vec3f> circles;

        HoughCircles( srcgray, circles, CV_HOUGH_GRADIENT, 1, srcgray.rows/8, 200, 100, 0, 0 );
        for( size_t i = 0; i < circles.size(); i++ )
        {
            Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
            int radius = cvRound(circles[i][2]);
            circle( src, center, radius, Scalar(0,255,0), 3, 8, 0 );
        }
        namedWindow( "Hough Circle Transform Demo", CV_WINDOW_AUTOSIZE );
        imshow( "Hough Circle Transform Demo", src );
        int c=cvWaitKey(10);
        if(char(c)==27)
            break;
    }
    return 0;
}

以下给出了用于在不使用相机时测试程序的样本：|

Answer 1

修改

我错了。 cv :: houghCircles不需要边作为输入。你需要的只是好的参数。我已经检查过opencv实现，并且已经在内部进行了sobel。感谢@micka进行更正

---

霍夫需要边缘作为输入。我稍微修改了你的程序，并通过将网络摄像头指向监视器来验证它是否正常工作。

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <opencv/cv.h>
#include <iostream>
#include <stdio.h>

using namespace cv;

int main(int argc, char** argv)
{
    CvCapture* capture=0;
    capture=cvCaptureFromCAM(0);
    if(!capture)
    {
        printf("Capture failure\n");
        return -1;
    }

    int dp=1,mindist=100,param1=300,param2=60,minradius=0,maxradius=0;
    cv::namedWindow("ctrl");
    cv::createTrackbar( "dp", "ctrl", &dp, 50);
    cv::createTrackbar( "mindist", "ctrl", &mindist, 1000);
    cv::createTrackbar( "param1", "ctrl", &param1, 1000);
    cv::createTrackbar( "param2", "ctrl", &param2, 1000);
    cv::createTrackbar( "minradius", "ctrl", &minradius, 1000);
    cv::createTrackbar( "maxradius", "ctrl", &maxradius, 1000);
    IplImage* frame;
    while(true)
    {
        frame=cvQueryFrame(capture);
        if(!frame) break;
        Mat src(frame);
        IplImage* framegray=cvCreateImage(cvGetSize(frame),8,3);
        Mat srcgray(framegray);
        cvtColor(src,srcgray,CV_BGR2GRAY);
        vector<Vec3f> circles;

        HoughCircles( srcgray, circles, CV_HOUGH_GRADIENT, dp,mindist, param1, param2, minradius, maxradius );
        for( size_t i = 0; i < circles.size(); i++ )
        {
            Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
            int radius = cvRound(circles[i][2]);
            circle( src, center, radius, Scalar(0,255,0), 3, 8, 0 );
        }
        namedWindow( "Hough Circle Transform Demo", CV_WINDOW_AUTOSIZE );
        imshow( "Hough Circle Transform Demo", src );
        cvReleaseImage(&framegray);
        int c=cvWaitKey(1);
        if(char(c)==27)
            break;
    }
    return 0;
} 

Answer 2

尝试使用您的代码，它可以与您的测试图像配合使用。我不再使用IplImage将代码更改为一致的c ++ openCV语法。

void identifyCircles()
{

    cv::Mat src = cv::imread("identifyCircles2.png");

    cv::Mat srcgray;
    cv::cvtColor(src,srcgray,CV_BGR2GRAY);
    cv::GaussianBlur(srcgray,srcgray,Size(9, 9), 2, 2 );
    std::vector<cv::Vec3f> circles;

    cv::HoughCircles( srcgray, circles, CV_HOUGH_GRADIENT, 1, srcgray.rows/8, 200, 100, 0, 0 );
    for( size_t i = 0; i < circles.size(); i++ )
    {
        cv::Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
        int radius = cvRound(circles[i][2]);
        circle( src, center, radius, cv::Scalar(0,255,0), 3, 8, 0 );
    }
    cv::namedWindow( "Hough Circle Transform Demo", CV_WINDOW_AUTOSIZE );
    cv::imshow( "Hough Circle Transform Demo", src );
    cv::imwrite("houghCirclesIdentified.png",src);
    cv::waitKey(-1);

}

给我输出：

所以您的问题可能是视频流输入，那里的圈子可能不够“好”。或者您的图像未正确流式传输（图像是否显示？！？）。

如果未输入for loop，circles.size() is <= 0，您可能需要添加std::cout << "circles found in this image: " << circles.size() << std::endl或if(circles.size() == 0) std::cout << "no circles found" << std::endl进行调试。