c++ - Save what's inside of a circle detected by a Hough Circle on OpenCV -

i'm using hough circle transform opencv detect circles images passed command line parameter. need save information inside determined circle (shape , colors), defined specific color. actual code following:

// read image while(*argv){     images_read[i] = cv::imread(*argv, 1);      if(!images_read[i].data){         std::cout << "image " << *argv << " couldn't read!\n";         exit(-1);     }      ++argv;     ++i; }  array_size = i;  /// convert gray for(i = 0; < array_size; ++i){     cv::cvtcolor(images_read[i], images_gray[i], cv_bgr2gray);      /// reduce noise avoid false circle detection     cv::gaussianblur(images_gray[i], images_gray[i], cv::size(9, 9), 2, 2);     //cvsmooth(images_gray[i], images_gray[i], cv_gaussian, 7, 7);      /// apply hough transform find circles     cv::houghcircles(images_gray[i], circles[i], cv_hough_gradient, 1, images_gray[i].rows / 8, 200, 100, 0, 0); } 

how can that? thanks.

i don't have complete grasp of code. however, can save image of bounding rectangle circle following. first find center of given circle.

// assuming variable circle output houghcircles cv::point center(cvround(circle[0]),cvround(circles[1])); 

then find radius.

int radius = cvround(circle[2]); 

given center , radius can create new image circles bounding rectangle

// assuming src original image cv::mat boundingrectangle(images_read[i], cv::rect(               cv::point(                   center.x - radius,                   center.y - radius                   ),               cv::point(                   center.x + radius,                   center.y + radius                   )               )); 

and save following

cv::imwrite("/path/to/file", boundingrectangle); 

so putting end following

#include <vector> #include <sstream> #include <string>  int main(int argc, char **argv) {     std::vector<cv::mat> images_read;     std::vector<std::string> image_names;      // read image     for(size_t = 1; < argc; ++i) {         cv::mat tmp = cv::imread(argv[i], 1);          if(!tmp.data){             std::cout << "image " << *argv << " couldn't read!\n";             exit(-1);         }         images_read.push_back(tmp);         image_names.push_back(argv[i]);     }      std::vector<cv::mat> images_gray(images_read.size());      // convert gray     for(size_t = 0; < images_read.size(); ++i){         cv::cvtcolor(images_read[i], images_gray[i], cv_bgr2gray);          // reduce noise avoid false circle detection         cv::gaussianblur(images_gray[i], images_gray[i], cv::size(9, 9), 2, 2);          // apply hough transform find circles         std::vector<cv::vec3f> circles;         cv::houghcircles(images_gray[i], circles, cv_hough_gradient,1,             images_gray[i].rows / 8, 200, 100, 0, 0);          // loop through of circles found , write them         for(size_t j = 0; j < circles.size(); ++j) {             cv::point center(                          cvround(circles[j][0]),                          cvround(circles[j][1])                         );             int radius = cvround(circles[j][2]);              // create image bounding             // rectangle using center , radius             cv::mat boundingrectangle(images_read[i], cv::rect(                        cv::point(                                  center.x - radius,                                  center.y - radius                                  ),                        cv::point(                                  center.x + radius,                                  center.y + radius                                  )                                 ));             std::string tmp = std::string(image_names[i]);             // assuming files you're reading jpeg images             std::string output = std::string(tmp, 0, tmp.find(".jpg"));                   std::ostringstream os;             os << "-" << j << ".jpg";              output += os.str();              cv::imwrite(output, boundingrectangle);         }     }     return 0; } 

the key parts including finding radius, center, , creating image bounding rectangle of circle.

the image inside bounding rectangle saved file path number of j after it.