find论文的angular落

我是openCV的新手，从最近3天到4天都在努力工作，我已经检测到了纸张边界，现在我想在angular落画4个圆。

我从这个代码中划出边界

const cv::Point* p = &squares[i][0]; int n = (int)squares[i].size(); polylines(image, &p,&n, 1, true, Scalar(255,255,0), 5, CV_AA); 

我在openCV中是新的，所以我认为我有左上angular的点p-> x和p-> y，但是我怎样得到其他的angular，我也混淆了这个多义线方法中的参数＆n，这个多义线方法绘制完整的矩形？

当我使用边界矩形时，它不是完美的给纸面上的一点点空间。

任何帮助真的很感激

代码是：

 - (cv::Mat)finshWork:(cv::Mat &)image { // read in the apple (change path to the file) Mat img0 =image;// imread("/home/philipp/img/apple.jpg", 1); Mat img1; cvtColor(img0, img1, CV_RGB2GRAY); // apply your filter Canny(img1, img1, 100, 200); // find the contours vector< vector<cv::Point> > contours; findContours(img1, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE); /////for SQUARE CODE std::vector<std::vector<cv::Point> > squares; std::vector<cv::Point> approx; for( size_t i = 0; i < contours.size(); i++ ) { cv::approxPolyDP(cv::Mat(contours[i]), approx, arcLength(cv::Mat(contours[i]), true)*0.02, true); if( approx.size() == 4 && fabs(contourArea(cv::Mat(approx))) > 1000 && cv::isContourConvex(cv::Mat(approx))) { double maxCosine = 0; for( int j = 2; j < 5; j++ ) { double cosine = fabs(angle(approx[j%4], approx[j-2], approx[j-1])); maxCosine = MAX(maxCosine, cosine); } if( maxCosine < 0.3 ) { squares.push_back(approx); cv::Point newPoint = approx[0]; NSLog(@"x is %d and y is %d",newPoint.x,newPoint.y); } } } const cv::Point* p = &squares[0][0]; int n = (int)squares[0].size(); NSLog(@"%d",n); //THIS IS WORKING CODE polylines(image, &p,&n, 1, true, Scalar(0,0,255), 10, CV_AA); //polylines(image, &p,&n, 1, true, Scalar(255,255,0), 5, CV_AA); //////////// } 

谢谢

Answer 1

参考我的原始代码 ，它只是检测图像上的正方形。

这意味着在应用程序的主要方法中，您可以编写如下的伪代码来调用find_squares() ：

 Mat image = imread("test.jpg", 1); // Detect all regions in the image that are similar to a rectangle vector<vector<Point> > squares; find_squares(image, squares); // The largest of them probably represents the paper vector<Point> largest_square; find_largest_square(squares, largest_square); // Print the x,y coordinates of the square cout << "Point 1: " << largest_square[0] << endl; cout << "Point 2: " << largest_square[1] << endl; cout << "Point 3: " << largest_square[2] << endl; cout << "Point 4: " << largest_square[3] << endl; 

这个技巧依赖于find_largest_square()如下：

 void find_largest_square(const vector<vector<Point> >& squares, vector<Point>& biggest_square) { if (!squares.size()) { // no squares detected return; } int max_width = 0; int max_height = 0; int max_square_idx = 0; const int n_points = 4; for (size_t i = 0; i < squares.size(); i++) { // Convert a set of 4 unordered Points into a meaningful cv::Rect structure. Rect rectangle = boundingRect(Mat(squares[i])); // cout << "find_largest_square: #" << i << " rectangle x:" << rectangle.x << " y:" << rectangle.y << " " << rectangle.width << "x" << rectangle.height << endl; // Store the index position of the biggest square found if ((rectangle.width >= max_width) && (rectangle.height >= max_height)) { max_width = rectangle.width; max_height = rectangle.height; max_square_idx = i; } } biggest_square = squares[max_square_idx]; }