hao_LARGEST_CONTOUR

package test;
import java.awt.image.*;
import java.io.*;

import javax.imageio.*;

import org.bytedeco.javacpp.Loader;
import org.bytedeco.javacpp.Pointer;
import org.bytedeco.javacpp.opencv_core.CvContour;
import org.bytedeco.javacpp.opencv_core.CvMemStorage;
import org.bytedeco.javacpp.opencv_core.CvSeq;
import org.bytedeco.javacpp.opencv_core.IplImage;
import org.bytedeco.javacpp.opencv_highgui;

import static org.bytedeco.javacpp.helper.opencv_imgproc.cvFindContours;
import static org.bytedeco.javacpp.opencv_core.*;
import static org.bytedeco.javacpp.opencv_highgui.*;
import static org.bytedeco.javacpp.opencv_imgproc.*;

public class CannyContour {
    public static void main(String[] args) {
        imageToContour("C:\\Documents and Settings\\Hao\\Desktop\\skull.jpg");
    }

    public static void imageToContour (String srcPath) {
        IplImage src = cvLoadImage(srcPath);
        IplImage grayImage = IplImage.create(src.width(), src.height(), IPL_DEPTH_8U, 1);
        cvCvtColor(src, grayImage, CV_BGR2GRAY);


        CvSeq contours = new CvSeq();
        cvThreshold(grayImage, grayImage, 10, 255, CV_THRESH_BINARY);
//      cvCanny(grayImage, grayImage, 100, 200, 3);
        CvMemStorage memory = CvMemStorage.create();
        cvFindContours(grayImage, memory, contours, Loader.sizeof(CvContour.class), CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0));
//      while(contours!=null && !contours.isNull()){
//          System.out.println("Elem size: " + contours.elem_size());
//          System.out.println("Total: " + contours.total());
//          if(contours.elem_size()>0 && contours.total()>=1){
//              CvSeq point = cvApproxPoly(contours, Loader.sizeof(CvContour.class), memory, CV_POLY_APPROX_DP, cvContourPerimeter(contours)*0.00002, 0);
//              cvDrawContours(src, point, CvScalar.YELLOW, CvScalar.RED, -1, 1, CV_AA);
//          }
//          contours = contours.h_next();
//      }
        ///////////////////////////////////////////////////////
        CvSeq largestContour = new CvSeq();
        double largestArea = 0;
        while(contours!=null && !contours.isNull()){
            double area = cvContourArea(contours);
            System.out.println(contours.total());
            System.out.println("Area: " + area);
            System.out.println("Largest Area: " + largestArea);
            if(area>0) {
                if(area>largestArea){
                    largestArea = area;
                    largestContour = contours;
                }
            }
            contours = contours.h_next();
        }
        /////////////////////////////////////////////////////////

        System.out.println("total: " + largestContour.total());
        CvSeq point = cvApproxPoly(largestContour, Loader.sizeof(CvContour.class), memory, CV_POLY_APPROX_DP, cvContourPerimeter(largestContour)*0.00002, 0);
        cvDrawContours(src, point, CvScalar.YELLOW, CvScalar.RED, -1, 1, CV_AA);

        String path = "C:\\Documents and Settings\\Hao\\Desktop\\target.jpg";
        cvSaveImage(path, src);
        System.exit(0);
    }
}