笔尖检测，C++ opencv

Question

我正在尝试用绿色标记笔尖。我写了一个程序，但它不能正确标记它。我尝试了不同的 HSV 值，但结果是一样的。是我的方法错了还是我的方法有小错误？

我的代码；

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <string>
#include <iostream>

using namespace std;
using namespace cv;
int main(){

Mat image = imread("C:/denem5.jpg");
Mat bwRed;
Mat hsvImage;
int BiggestAreaIdx = 0;
int BiggestAreaValue = 20;
cvtColor(image, hsvImage, CV_BGR2HSV);
inRange(hsvImage, Scalar(130, 70, 70), Scalar(179, 255, 255), bwRed);
vector<vector<Point>> contours;
findContours(bwRed,
    contours,
    CV_RETR_TREE,
    CV_CHAIN_APPROX_SIMPLE);

//Here I find biggest contour because others are noise
for (int i = 0; i < contours.size(); i++)
{
    double area = contourArea(contours[i], false);
    if (area > BiggestAreaValue)
    {
        BiggestAreaValue = area;
        BiggestAreaIdx = i;
    }
}

Mat dst(image.size(), CV_8UC1, Scalar::all(0));
drawContours(dst, contours, BiggestAreaIdx, Scalar(255), CV_FILLED);

 vector<Moments> mu(contours.size() );
for( int i = 0; i < contours.size(); i++ )
   { mu[i] = moments( contours[i], false ); }

vector<Point2f> mc(contours.size());
 for (int i = 0; i < contours.size(); i++)
 {
  mc[i] = Point2f(mu[i].m10 / mu[i].m00, mu[i].m01 / mu[i].m00);
 }
 circle(image, Point(mc[BiggestAreaIdx]), 5, Scalar(0,255,0), 5, 8, 0);
 namedWindow("myimage");
 imshow("myimage",image);
 waitKey(0);
 }

原图

我的结果

Answer 1

既然是搜索圈子，可以用HoughCircles。这是一种不同的方法，有利有弊。

优点：

与笔的颜色无关
您不需要select正确的颜色值

缺点：

需要正确调整参数
如果你想要一个非圆圈就不行。

这里是代码：

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <string>
#include <iostream>

using namespace std;
using namespace cv;
int main(){

    Mat3b src = imread("path_to_image");
    Mat1b src_gray;
    cvtColor( src, src_gray, CV_BGR2GRAY );

    vector<Vec3f> circles;
    HoughCircles(src_gray, circles, CV_HOUGH_GRADIENT, 1, 10, 200, 30, 0, 0);

    /// Draw the circles detected
    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 center
        circle(src, center, 3, Scalar(0, 255, 0), -1, 8, 0);
        // circle outline
        circle(src, center, radius, Scalar(0, 0, 255), 3, 8, 0);
    }

    imshow("src", src);
    waitKey();

    return 0;
}

这里是结果：

笔尖检测，C++ opencv

Detecting point of a pen, C++ opencv

opencv

image-processing

object-detection