Tutorial for Generalized Hough Ballard and Guil Transform

2022-09-08 03:04:19 +02:00
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+/**
+  @file generalizedHoughTransform.cpp
+  @author Markus Heck
+  @brief Detects an object, given by a template, in an image using GeneralizedHoughBallard and GeneralizedHoughGuil.
+*/
+
+#include "opencv2/highgui.hpp"
+#include "opencv2/imgproc.hpp"
+
+using namespace cv;
+using namespace std;
+
+int main() {
+//  load source images
+    Mat image = imread("images/generalized_hough_mini_image.jpg");
+    Mat imgTemplate = imread("images/generalized_hough_mini_template.jpg");
+
+//  create grayscale image and template
+    Mat templ = Mat(imgTemplate.rows, imgTemplate.cols, CV_8UC1);
+    Mat grayImage;
+    cvtColor(imgTemplate, templ, COLOR_RGB2GRAY);
+    cvtColor(image, grayImage, COLOR_RGB2GRAY);
+
+//  create variable for location, scale and rotation of detected templates
+    vector<Vec4f> positionBallard, positionGuil;
+
+//  template width and height
+    int w = templ.cols;
+    int h = templ.rows;
+
+//  create ballard and set options
+    Ptr<GeneralizedHoughBallard> ballard = createGeneralizedHoughBallard();
+    ballard->setMinDist(10);
+    ballard->setLevels(360);
+    ballard->setDp(2);
+    ballard->setMaxBufferSize(1000);
+    ballard->setVotesThreshold(40);
+
+    ballard->setCannyLowThresh(30);
+    ballard->setCannyHighThresh(110);
+    ballard->setTemplate(templ);
+
+
+//  create guil and set options
+    Ptr<GeneralizedHoughGuil> guil = createGeneralizedHoughGuil();
+    guil->setMinDist(10);
+    guil->setLevels(360);
+    guil->setDp(3);
+    guil->setMaxBufferSize(1000);
+
+    guil->setMinAngle(0);
+    guil->setMaxAngle(360);
+    guil->setAngleStep(1);
+    guil->setAngleThresh(1500);
+
+    guil->setMinScale(0.5);
+    guil->setMaxScale(2.0);
+    guil->setScaleStep(0.05);
+    guil->setScaleThresh(50);
+
+    guil->setPosThresh(10);
+
+    guil->setCannyLowThresh(30);
+    guil->setCannyHighThresh(110);
+
+    guil->setTemplate(templ);
+
+
+//  execute ballard detection
+    ballard->detect(grayImage, positionBallard);
+//  execute guil detection
+    guil->detect(grayImage, positionGuil);
+
+
+//  draw ballard
+    for (vector<Vec4f>::iterator iter = positionBallard.begin(); iter != positionBallard.end(); ++iter) {
+        RotatedRect rRect = RotatedRect(Point2f((*iter)[0], (*iter)[1]),
+                                        Size2f(w * (*iter)[2], h * (*iter)[2]),
+                                        (*iter)[3]);
+        Point2f vertices[4];
+        rRect.points(vertices);
+        for (int i = 0; i < 4; i++)
+            line(image, vertices[i], vertices[(i + 1) % 4], Scalar(255, 0, 0), 6);
+    }
+
+//  draw guil
+    for (vector<Vec4f>::iterator iter = positionGuil.begin(); iter != positionGuil.end(); ++iter) {
+        RotatedRect rRect = RotatedRect(Point2f((*iter)[0], (*iter)[1]),
+                                        Size2f(w * (*iter)[2], h * (*iter)[2]),
+                                        (*iter)[3]);
+        Point2f vertices[4];
+        rRect.points(vertices);
+        for (int i = 0; i < 4; i++)
+            line(image, vertices[i], vertices[(i + 1) % 4], Scalar(0, 255, 0), 2);
+    }
+
+    imshow("result_img", image);
+    waitKey();
+    return EXIT_SUCCESS;
+}