Working on undistortion. Currently at the experimental example phase.

Author: atduskgreg

examples/WarpPerspective/WarpPerspective.pde

@@ -0,0 +1,76 @@
+import gab.opencv.*;
+import org.opencv.imgproc.Imgproc;
+import org.opencv.core.MatOfPoint2f;
+import org.opencv.core.Point;
+import org.opencv.core.Size;
+
+import org.opencv.core.Mat;
+import org.opencv.core.CvType;
+
+
+OpenCV opencv;
+PImage src;
+PImage card;
+int cardWidth = 250;
+int cardHeight = 350;
+
+Contour contour;
+
+void setup() {
+  src = loadImage("cards.png");
+  size(src.width + cardWidth, src.height);
+  opencv = new OpenCV(this, src);
+
+  opencv.blur(1);
+  opencv.threshold(120);
+
+  contour = opencv.findContours(false, true).get(0).getPolygonApproximation();
+
+  card = createImage(cardWidth, cardHeight, ARGB);  
+  opencv.toPImage(warpPerspective(contour.getPoints(), cardWidth, cardHeight), card);
+}
+
+Mat getPerspectiveTransformation(ArrayList<PVector> inputPoints, int w, int h) {
+  Point[] canonicalPoints = new Point[4];
+  canonicalPoints[0] = new Point(w, 0);
+  canonicalPoints[1] = new Point(0, 0);
+  canonicalPoints[2] = new Point(0, h);
+  canonicalPoints[3] = new Point(w, h);
+
+  MatOfPoint2f canonicalMarker = new MatOfPoint2f();
+  canonicalMarker.fromArray(canonicalPoints);
+
+  Point[] points = new Point[4];
+  for (int i = 0; i < 4; i++) {
+    points[i] = new Point(inputPoints.get(i).x, inputPoints.get(i).y);
+  }
+  MatOfPoint2f marker = new MatOfPoint2f(points);
+  return Imgproc.getPerspectiveTransform(marker, canonicalMarker);
+}
+
+Mat warpPerspective(ArrayList<PVector> inputPoints, int w, int h) {
+  Mat transform = getPerspectiveTransformation(inputPoints, w, h);
+  Mat unWarpedMarker = new Mat(w, h, CvType.CV_8UC1);    
+  Imgproc.warpPerspective(opencv.getColor(), unWarpedMarker, transform, new Size(w, h));
+  return unWarpedMarker;
+}
+
+
+void draw() {
+  image(src, 0, 0);
+  noFill(); 
+  stroke(0, 255, 0); 
+  strokeWeight(4);
+  contour.draw();
+  fill(255, 0);
+  ArrayList<PVector> points = contour.getPoints();
+  for (int i = 0; i < points.size(); i++) {
+    text(i, points.get(i).x, points.get(i).y);
+  }
+
+  pushMatrix();
+  translate(src.width, 0);
+  image(card, 0, 0);
+  popMatrix();
+}
+

examples/WarpPerspective/cards.png

@@ -173,6 +173,14 @@ An advanced example. Calculates depth information from a pair of stereo images.
 
 Code: [DepthFromStereo.pde](https://github.com/atduskgreg/opencv-processing/blob/master/examples/DepthFromStereo/DepthFromStereo.pde)
 
+#### WarpPerspective (in progress)
+
+Un-distort an object that's in perspective. Coming to the real API soon.
+
+<a href="http://www.flickr.com/photos/unavoidablegrain/9279197332/" title="Warp Perspective by atduskgreg, on Flickr"><img src="http://farm3.staticflickr.com/2861/9279197332_ca6beb3760.jpg" width="500" height="416" alt="Warp Perspective"></a>
+
+Code: [WarpPerspective.pde](https://github.com/atduskgreg/opencv-processing/blob/master/examples/WarpPerspective/WarpPerspective.pde)
+
 #### MarkerDetection
 
 An in-depth advanced example. Detect a CV marker in an image, warp perspective, and detect the number stored in the marker. Many steps in the code. Uses many un-wrapped OpenCV objects and functions.

readme.md

@@ -73,7 +73,7 @@ public void draw(){
 		for (PVector p : points) {
 			parent.vertex(p.x, p.y);
 		}
-		parent.endShape();
+		parent.endShape(PConstants.CLOSE);
 
 	}
 

src/gab/opencv/Contour.java

@@ -326,15 +326,17 @@ public void loadCascade(String cascadeFileName){
 		// localize path to cascade file to point at the library's data folder
 		String relativePath = "data/" + cascadeFileName;		
 		String jarPath = getClass().getProtectionDomain().getCodeSource().getLocation().getPath();
-
+		
 		String[] parts = jarPath.split("/");
 
 		String cascadePath = "";
 		for(int i = 0; i < parts.length-2; i++){
 			cascadePath += parts[i] + "/";
 		}
 		cascadePath += relativePath;
-		
+				
+		PApplet.println("Load cascade from: " + cascadePath);
+
 		classifier = new CascadeClassifier(cascadePath);   
 
         if(classifier.empty()){
@@ -521,18 +523,7 @@ public ArrayList<Contour> findContours(){
 		return findContours(true, false);
 	}
 
-	public ArrayList<Line> findLines(int threshold, double minLineLength, double maxLineGap){
-		ArrayList<Line> result = new ArrayList<Line>();
-		
-		Mat lineMat = new Mat();
-		Imgproc.HoughLinesP(getCurrentMat(), lineMat, 1, PConstants.PI/180.0, threshold, minLineLength, maxLineGap);
-		for (int i = 0; i < lineMat.width(); i++) {
-			double[] coords = lineMat.get(0, i);
-		    result.add(new Line(coords[0], coords[1], coords[2], coords[3]));
-		}
-		
-		return result;
-	}
+	
 
 	public ArrayList<Contour> findContours(boolean findHoles, boolean sort){
 		ArrayList<Contour> result = new ArrayList<Contour>();
@@ -556,6 +547,21 @@ public ArrayList<Contour> findContours(boolean findHoles, boolean sort){
 		return result;
 	}
 
+	public ArrayList<Line> findLines(int threshold, double minLineLength, double maxLineGap){
+		ArrayList<Line> result = new ArrayList<Line>();
+		
+		Mat lineMat = new Mat();
+		Imgproc.HoughLinesP(getCurrentMat(), lineMat, 1, PConstants.PI/180.0, threshold, minLineLength, maxLineGap);
+		for (int i = 0; i < lineMat.width(); i++) {
+			double[] coords = lineMat.get(0, i);
+		    result.add(new Line(coords[0], coords[1], coords[2], coords[3]));
+		}
+		
+		return result;
+	}
+	
+	
+	
 	public ArrayList<PVector> findChessboardCorners(int patternWidth, int patternHeight){
 		MatOfPoint2f corners = new MatOfPoint2f();
 		Calib3d.findChessboardCorners(getCurrentMat(), new Size(patternWidth,patternHeight), corners);