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;
}