added holes to ContourFinder, closes #21

Author: kylemcdonald

example-contours-advanced/src/ofApp.cpp

@@ -12,13 +12,15 @@ void ofApp::setup() {
     gui.setup();
     gui.add(threshold.set("Threshold", 128, 0, 255));
     gui.add(trackHs.set("Track Hue/Saturation", false));
+    gui.add(holes.set("Holes", false));
 }
 
 void ofApp::update() {
 	cam.update();
     if(cam.isFrameNew()) {
         contourFinder.setTargetColor(targetColor, trackHs ? TRACK_COLOR_HS : TRACK_COLOR_RGB);
 		contourFinder.setThreshold(threshold);
+        contourFinder.setFindHoles(holes);
 		contourFinder.findContours(cam);
 	}
 }
@@ -91,11 +93,15 @@ void ofApp::draw() {
 		ofScale(5, 5);
 		ofDrawLine(0, 0, balance.x, balance.y);
 		ofPopMatrix();
+        
+        if(contourFinder.getHole(i)) {
+            ofDrawBitmapStringHighlight("hole", center.x, center.y);
+        }
 	}
 
     gui.draw();
 
-	ofTranslate(8, 75);
+	ofTranslate(8, 90);
 	ofFill();
 	ofSetColor(0);
 	ofDrawRectangle(-3, -3, 64+6, 64+6);

example-contours-advanced/src/ofApp.h

@@ -18,4 +18,5 @@ class ofApp : public ofBaseApp {
     ofxPanel gui;
     ofParameter<float> threshold;
     ofParameter<bool> trackHs;
+    ofParameter<bool> holes;
 };

example-contours-basic/src/ofApp.cpp

@@ -9,6 +9,7 @@ void ofApp::setup() {
     gui.add(minArea.set("Min area", 10, 1, 100));
     gui.add(maxArea.set("Max area", 200, 1, 500));
     gui.add(threshold.set("Threshold", 128, 0, 255));
+    gui.add(holes.set("Holes", false));
 }
 
 void ofApp::update() {
@@ -18,6 +19,7 @@ void ofApp::update() {
         contourFinder.setMaxAreaRadius(maxArea);
 		contourFinder.setThreshold(threshold);
 		contourFinder.findContours(cam);
+        contourFinder.setFindHoles(holes);
 	}
 }
 

example-contours-basic/src/ofApp.h

@@ -15,4 +15,5 @@ class ofApp : public ofBaseApp {
 
     ofxPanel gui;
     ofParameter<float> minArea, maxArea, threshold;
+    ofParameter<bool> holes;
 };

libs/CLD/addons.make

@@ -64,7 +64,8 @@ namespace ofxCv {
 		cv::RotatedRect getMinAreaRect(unsigned int i) const;
 		cv::Point2f getMinEnclosingCircle(unsigned int i, float& radius) const;
 		cv::RotatedRect getFitEllipse(unsigned int i) const;
-		std::vector<cv::Point> getFitQuad(unsigned int i) const;
+        std::vector<cv::Point> getFitQuad(unsigned int i) const;
+        bool getHole(unsigned int i) const;
 		cv::Vec2f getVelocity(unsigned int i) const;
 
 		RectTracker& getTracker();
@@ -107,7 +108,8 @@ namespace ofxCv {
 		std::vector<ofPolyline> polylines;
 
 		RectTracker tracker;
-		std::vector<cv::Rect> boundingRects;
+        std::vector<cv::Rect> boundingRects;
+        std::vector<bool> holes;
 
 		int contourFindingMode;
 		bool sortBySize;

libs/ofxCv/addons.make

@@ -75,12 +75,19 @@ namespace ofxCv {
 		bool needMaxFilter = maxAreaNorm ? (maxArea < 1) : (maxArea < numeric_limits<float>::infinity());
 		vector<size_t> allIndices;
 		vector<double> allAreas;
+        vector<bool> allHoles;
 		if(needMinFilter || needMaxFilter) {
 			double imgArea = img.rows * img.cols;
 			double imgMinArea = minAreaNorm ? (minArea * imgArea) : minArea;
 			double imgMaxArea = maxAreaNorm ? (maxArea * imgArea) : maxArea;
 			for(size_t i = 0; i < allContours.size(); i++) {
-				double curArea = contourArea(Mat(allContours[i]));
+				double curArea = contourArea(Mat(allContours[i]), true);
+                bool hole = true;
+                if(curArea < 0) {
+                    curArea = -curArea;
+                    hole = false;
+                }
+                allHoles.push_back(hole);
 				allAreas.push_back(curArea);
 				if((!needMinFilter || curArea >= imgMinArea) &&
 					 (!needMaxFilter || curArea <= imgMaxArea)) {
@@ -104,11 +111,13 @@ namespace ofxCv {
 		// generate polylines and bounding boxes from the contours
 		contours.clear();
 		polylines.clear();
-		boundingRects.clear();
+        boundingRects.clear();
+        holes.clear();
 		for(size_t i = 0; i < allIndices.size(); i++) {
 			contours.push_back(allContours[allIndices[i]]);
 			polylines.push_back(toOf(contours[i]));
 			boundingRects.push_back(boundingRect(contours[i]));
+            holes.push_back(allHoles[allIndices[i]]);
 		}
 
 		// track bounding boxes
@@ -248,12 +257,16 @@ namespace ofxCv {
 		}
 
 		return quad;
-	}
+    }
+    
+    bool ContourFinder::getHole(unsigned int i) const {
+        return holes[i];
+    }
 
 	cv::Vec2f ContourFinder::getVelocity(unsigned int i) const {
 		return tracker.getVelocity(i);
 	}
-	
+    
 	unsigned int ContourFinder::getLabel(unsigned int i) const {
 		return tracker.getCurrentLabels()[i];
 	}