private static Mat findLargestRectangle(Mat original_image) { Mat imgSource = original_image.clone(); // convert the image to black and white Imgproc.cvtColor(imgSource, imgSource, Imgproc.COLOR_BGR2GRAY); // convert the image to black and white does (8 bit) Imgproc.Canny(imgSource, imgSource, 50, 50); // apply gaussian blur to smoothen lines of dots Imgproc.GaussianBlur(imgSource, imgSource, new Size(5, 5), 5); // find the contours List<MatOfPoint> contours = new ArrayList<MatOfPoint>(); Imgproc.findContours( imgSource, contours, new Mat(), Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE); double maxArea = -1; MatOfPoint temp_contour = contours.get(0); // the largest is at the // index 0 for starting // point MatOfPoint2f approxCurve = new MatOfPoint2f(); List<MatOfPoint> largest_contours = new ArrayList<MatOfPoint>(); for (int idx = 0; idx < contours.size(); idx++) { temp_contour = contours.get(idx); double contourarea = Imgproc.contourArea(temp_contour); // compare this contour to the previous largest contour found if (contourarea > maxArea) { // check if this contour is a square MatOfPoint2f new_mat = new MatOfPoint2f(temp_contour.toArray()); int contourSize = (int) temp_contour.total(); Imgproc.approxPolyDP(new_mat, approxCurve, contourSize * 0.05, true); if (approxCurve.total() == 4) { maxArea = contourarea; largest_contours.add(temp_contour); } } } MatOfPoint temp_largest = largest_contours.get(largest_contours.size() - 1); largest_contours = new ArrayList<MatOfPoint>(); largest_contours.add(temp_largest); // Imgproc.cvtColor(imgSource, imgSource, Imgproc.COLOR_BayerBG2RGB); Imgproc.drawContours(original_image, largest_contours, -1, new Scalar(0, 255, 0), 10); // Mat perspectiveTransform = new Mat(3, 3, CvType.CV_32FC1); // Imgproc.warpPerspective(original_image, imgSource, // perspectiveTransform, new Size(300,300)); Highgui.imwrite(output, original_image); // create the new image here using the largest detected square // Toast.makeText(getApplicationContext(), "Largest Contour: ", // Toast.LENGTH_LONG).show(); return imgSource; }
public static void getSquare(Mat imgSource) { Mat sourceImage = imgSource.clone(); Imgproc.cvtColor(imgSource, imgSource, Imgproc.COLOR_BGR2GRAY); // convert the image to black and white does (8 bit) Imgproc.Canny(imgSource, imgSource, 50, 50); // apply gaussian blur to smoothen lines of dots Imgproc.GaussianBlur(imgSource, imgSource, new org.opencv.core.Size(5, 5), 5); // find the contours List<MatOfPoint> contours = new ArrayList<MatOfPoint>(); Imgproc.findContours( imgSource, contours, new Mat(), Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE); double maxArea = -1; int maxAreaIdx = -1; // Log.d("size",Integer.toString(contours.size())); MatOfPoint temp_contour = contours.get(0); // the largest is at the // index 0 for starting // point MatOfPoint2f approxCurve = new MatOfPoint2f(); MatOfPoint largest_contour = contours.get(0); // largest_contour.ge List<MatOfPoint> largest_contours = new ArrayList<MatOfPoint>(); // Imgproc.drawContours(imgSource,contours, -1, new Scalar(0, 255, 0), // 1); for (int idx = 0; idx < contours.size(); idx++) { temp_contour = contours.get(idx); double contourarea = Imgproc.contourArea(temp_contour); // compare this contour to the previous largest contour found if (contourarea > maxArea) { // check if this contour is a square MatOfPoint2f new_mat = new MatOfPoint2f(temp_contour.toArray()); int contourSize = (int) temp_contour.total(); MatOfPoint2f approxCurve_temp = new MatOfPoint2f(); Imgproc.approxPolyDP(new_mat, approxCurve_temp, contourSize * 0.05, true); if (approxCurve_temp.total() == 4) { maxArea = contourarea; maxAreaIdx = idx; approxCurve = approxCurve_temp; largest_contour = temp_contour; } } } Imgproc.cvtColor(imgSource, imgSource, Imgproc.COLOR_BayerBG2RGB); double[] temp_double; temp_double = approxCurve.get(0, 0); Point p1 = new Point(temp_double[0], temp_double[1]); // Core.circle(imgSource,p1,55,new Scalar(0,0,255)); // Imgproc.warpAffine(sourceImage, dummy, rotImage,sourceImage.size()); temp_double = approxCurve.get(1, 0); Point p2 = new Point(temp_double[0], temp_double[1]); // Core.circle(imgSource,p2,150,new Scalar(255,255,255)); temp_double = approxCurve.get(2, 0); Point p3 = new Point(temp_double[0], temp_double[1]); // Core.circle(imgSource,p3,200,new Scalar(255,0,0)); temp_double = approxCurve.get(3, 0); Point p4 = new Point(temp_double[0], temp_double[1]); // Core.circle(imgSource,p4,100,new Scalar(0,0,255)); List<Point> source = getCorners(p1, p2, p3, p4); for (Point p : source) { // System.out.println(p); } Mat startM = Converters.vector_Point2f_to_Mat(source); // Imgproc.cvtColor(sourceImage, sourceImage, Imgproc.COLOR_BGR2GRAY); Mat result = warp(sourceImage, startM, 5); // result = warp(result,result,1); // Imgproc.cvtColor(result, result, Imgproc.COLOR_BGR2GRAY); Highgui.imwrite(output, result); // System.out.println("Done"); // return result; }