opcv检测直线交叉_opencv4 学习 13 直线和圆形的检测

1、直线检测

HoughLines函数：保存到输出的是直线的极坐标公式参数

HoughLines(

InputArray image,

OutputArray lines,

double rho, double theta,

int threshold,

double srn = 0, double stn = 0,

double min_theta = 0, double max_theta = CV_PI );

HoughLinesP：保存到输出的是直线的端点

HoughLinesP(

InputArray image,

OutputArray lines,

double rho, double theta,

int threshold,

double minLineLength = 0,

double maxLineGap = 0

);

#include #include#include#include

using namespacecv;using namespacestd;int main(int argc, char*argv[])

{

Mat dst, cdst, cdstP;const char* filename = "sudoku.png";

Mat src=imread(filename, IMREAD_GRAYSCALE);

Canny(src,dst,50,200,3);

cvtColor(dst,cdst,COLOR_GRAY2BGR);

cdstP=cdst.clone();

vectorlines;

HoughLines(dst, lines,1, CV_PI/180,150,0,0);for(size_t i = 0; i < lines.size(); i++){float rho = lines[i][0], theta = lines[i][1];

Point pt1, pt2;double a = cos(theta), b =sin(theta);double x0 = a * rho, y0 = b *rho;

pt1.x= cvRound(x0 + 1000 * (-b));

pt1.y= cvRound(y0 + 1000 *(a));

pt2.x= cvRound(x0 - 1000 * (-b));

pt2.y= cvRound(y0 - 1000 *(a));

line(cdst, pt1, pt2, Scalar(0,0,255), 3, LINE_AA);

}

vectorlinesP;

HoughLinesP(dst, linesP,1, CV_PI/180, 50, 50, 10);for(size_t i = 0; i < linesP.size(); i++){

Vec4i l=linesP[i];

line(cdstP, Point(l[0],l[1]), Point(l[2],l[3]), Scalar(0,0,255),3,LINE_AA);

}

imshow("Source", src);

imshow("Strandard Hough Line Transform", cdst);

imshow("Probabilistic Line Transform", cdstP);

waitKey();returnEXIT_SUCCESS;

}

2、圆形检测

HoughCircles(

InputArray image,

OutputArray circles,

int method, \ 目前只实现了，CV_HOUGH_GRADIENT

double dp,

double minDist, \ 圆心之间的最小距离，值设太小，误检的圆会增多；值设太大，漏检的圆会增多

double param1 = 100, \ 对应canny算子中的2个阈值，该阈值对应是upper，lower参数upper的 1/2

double param2 = 100, \ 被检测为圆心的阈值

int minRadius = 0, \ 最小的圆半径

int maxRadius = 0 \ 最大的圆半径

);

#include #include#include#include

using namespacecv;using namespacestd;int main(int argc, char*argv[])

{

Mat src= imread("smarties.png", IMREAD_COLOR);

Mat gray;

cvtColor(src, gray, COLOR_BGR2GRAY);

medianBlur(gray, gray,5);

vectorcircles;

HoughCircles(gray, circles, HOUGH_GRADIENT,1, gray.rows/16, 100, 30, 1, 30);for(size_t i = 0; i < circles.size(); i++){

Vec3i c=circles[i];

Point center= Point(c[0], c[1]);

circle(src, center,1, Scalar(0, 100, 100), 3, LINE_AA);int radius = c[2];

circle(src, center, radius, Scalar(255, 0, 255), 3, LINE_AA);

}

imshow("detected circles", src);

waitKey();returnEXIT_SUCCESS;

}