opencv - Error matching with ORB in Android -

my code working when extracts keypoints, matches poorly 2 images. here can find code, don't know how draw matched in java android

 descriptors = new mat();         keypoints = new matofkeypoint();         detector = featuredetector.create(featuredetector.orb);         detector.detect(img1, keypoints);         descriptor = descriptorextractor.create(descriptorextractor.orb);         descriptor.compute(img1, keypoints, descriptors);         matcher = descriptormatcher.create(descriptormatcher.bruteforce_hamming);      colordetection.cvt_yuvtorgbtohsv(myuv,mgraysubmat);           matofkeypoint mkeypoints = new matofkeypoint();         matofdmatch  matches = new matofdmatch();            detector.detect(mgraysubmat, mkeypoints);           descriptor.compute(mgraysubmat, mkeypoints, mintermediatemat);          matcher.match(mintermediatemat,descriptors,matches);         mintermediatemat2.create(resultsize, cvtype.cv_8uc1);         features2d.drawmatches(img1, keypoints, mgraysubmat, mkeypoints, matches,                  mintermediatemat2,green, red,  match_mask, features2d.not_draw_single_points);            imgproc.resize(mintermediatemat2, mintermediatemat2, mrgba.size());           imgproc.cvtcolor(mintermediatemat2, mrgba, imgproc.color_rgba2bgra, 4);      utils.mattobitmap(mrgba, bmp);        dmatch dm[] = matches.toarray();           list<point> lp1 = new arraylist<point>(dm.length);           list<point> lp2 = new arraylist<point>(dm.length);           keypoint tkp[] = keypoints.toarray();           keypoint qkp[] = mkeypoints.toarray();           (int = 0; < dm.length; i++) {               dmatch dma = dm[i];               lp1.add(tkp[dma.trainidx].pt);               lp2.add(qkp[dma.queryidx].pt);           }           matofpoint2f pointsprev = new matofpoint2f(lp1.toarray(new point[0]));           matofpoint2f pointsact  = new matofpoint2f(lp2.toarray(new point[0]));         log.i("pointsprev", pointsprev.size().tostring());         log.i("pointsact", pointsact.size().tostring());           fundamental_matrix.create(resultsize, cvtype.cv_8uc1);         fundamental_matrix = calib3d.findfundamentalmat(                   pointsact, pointsprev, calib3d.fm_ransac, 3, 0.99); 

any suggestion?

edit :

i can't convert matches list ! because feature2d.drawmatches() need matofdmatch , not list<dmatch>

matofdmatch matches, matches12, matches21; matcher.match( descriptors1, descriptors2, matches12 ); matcher.match( descriptors2, descriptors1, matches21 );  iterate matches12     dmatch forward = matches12[i];       dmatch backward = matches21[forward.trainidx];      if( backward.trainidx == forward.queryidx )   //add forward matches  features2d.drawmatches(img1, keypoints, mgraysubmat, mkeypoints, matches,mintermediatemat2); 

your code should this:

 featuredetector detector = featuredetector.create(featuredetector.orb);  descriptorextractor descriptor = descriptorextractor.create(descriptorextractor.orb);;  descriptormatcher matcher = descriptormatcher.create(descriptormatcher.bruteforce_hamming);   //first image  mat img1 = highgui.imread("<image1 path>");  mat descriptors1 = new mat();  matofkeypoint keypoints1 = new matofkeypoint();   detector.detect(img1, keypoints1);  descriptor.compute(img1, keypoints1, descriptors1);   //second image  mat img2 = highgui.imread("<image2 path>");  mat descriptors2 = new mat();  matofkeypoint keypoints2 = new matofkeypoint();   detector.detect(img2, keypoints2);  descriptor.compute(img2, keypoints2, descriptors2);   //matcher should include 2 different image's descriptors  matofdmatch  matches = new matofdmatch();               matcher.match(descriptors1,descriptors2,matches);  //feature , connection colors  scalar red = new scalar(255,0,0);  scalar green = new scalar(0,255,0);  //output image  mat outputimg = new mat();  matofbyte drawnmatches = new matofbyte();  //this draw matches, works fine  features2d.drawmatches(img1, keypoints1, img2, keypoints2, matches,   outputimg, green, red,  drawnmatches, features2d.not_draw_single_points); 

also if want display features, can add code:

 mat featuredimg = new mat();  scalar kpcolor = new scalar(255,159,10);//this color of keypoints  //featuredimg output of first image  features2d.drawkeypoints(img1, keypoints1, featuredimg , kpcolor, 0);  //featuredimg output of first image  features2d.drawkeypoints(img1, keypoints1, featuredimg , kpcolor, 0); 

then can show matched points this:

  bitmap imagematched = bitmap.createbitmap(outputimg.cols(), outputimg.rows(), bitmap.config.rgb_565);//need save bitmap   utils.mattobitmap(outputimg, imagematched);   imageview.setimagebitmap(imagematched); 

eventually can implement matches. hope this thread helpful.