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asked 2017-11-27 06:35:16 -0600

PATDESSE gravatar image

using StereoBM in java on Android

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web... Regards

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updated 2017-11-27 18:34:15 -0600

opalmirror gravatar image

using StereoBM in java on Android

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web... Regards

using StereoBM in java on Android

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web... Regards

using StereoBM in java on Android

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web... Regardsweb...

UPDATE : I wrote the following java code :

                Mat rgba_left = Utils.loadResource(MainActivity.this, R.drawable.trampoline3d_gauche,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);
                Mat rgba_right = Utils.loadResource(MainActivity.this, R.drawable.trampoline3d_droite,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);

                Mat mleft= new Mat(rgba_left.size(), CvType.CV_8UC1);
                Mat mright= new Mat(rgba_right.size(), CvType.CV_8UC1);
                Mat mdisparity= new Mat(rgba_left.size(), CvType.CV_8UC1);

                Imgproc.cvtColor(rgba_left, mleft, Imgproc.COLOR_BGR2GRAY);
                Imgproc.cvtColor(rgba_right, mright, Imgproc.COLOR_BGR2GRAY);

                StereoBM stereo = StereoBM.create(16*5, 21);
                stereo.setPreFilterSize(5);
                stereo.setPreFilterCap(61);
                stereo.setMinDisparity(-10);
                stereo.setNumDisparities(16*5);
                stereo.setTextureThreshold(300);
                stereo.setUniquenessRatio(5);
                stereo.setSpeckleWindowSize(0);
                stereo.setSpeckleRange(8);

                stereo.compute(mleft, mright, mdisparity);

                Core.normalize(mdisparity,rgba_right,0,255,Core.NORM_MINMAX,CvType.CV_8UC1);

                Imgproc.cvtColor(rgba_right, rgba_left, Imgproc.COLOR_GRAY2BGRA, 4);
                Imgproc.resize(rgba_left, rgba, rgba.size());

but I obtain poor result ...

using StereoBM in java on Android

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web...

UPDATE : I wrote the following java code :

                Mat rgba_left = Utils.loadResource(MainActivity.this, R.drawable.trampoline3d_gauche,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);
                Mat rgba_right = Utils.loadResource(MainActivity.this, R.drawable.trampoline3d_droite,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);

                Mat mleft= new Mat(rgba_left.size(), CvType.CV_8UC1);
                Mat mright= new Mat(rgba_right.size(), CvType.CV_8UC1);
                Mat mdisparity= new Mat(rgba_left.size(), CvType.CV_8UC1);

                Imgproc.cvtColor(rgba_left, mleft, Imgproc.COLOR_BGR2GRAY);
                Imgproc.cvtColor(rgba_right, mright, Imgproc.COLOR_BGR2GRAY);

                StereoBM stereo = StereoBM.create(16*5, 21);
                stereo.setPreFilterSize(5);
                stereo.setPreFilterCap(61);
                stereo.setMinDisparity(-10);
                stereo.setNumDisparities(16*5);
                stereo.setTextureThreshold(300);
                stereo.setUniquenessRatio(5);
                stereo.setSpeckleWindowSize(0);
                stereo.setSpeckleRange(8);

                stereo.compute(mleft, mright, mdisparity);

                Core.normalize(mdisparity,rgba_right,0,255,Core.NORM_MINMAX,CvType.CV_8UC1);

                Imgproc.cvtColor(rgba_right, rgba_left, Imgproc.COLOR_GRAY2BGRA, 4);
                Imgproc.resize(rgba_left, rgba, rgba.size());

but I obtain poor result ...

left image : image description

right image : image description

result : image description

using StereoBM in java on Android

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web...

UPDATE : I wrote the following java code :

 // load left and right images
                Mat rgba_left = Utils.loadResource(MainActivity.this, Utils.loadResource(
                        MainActivity.this, 
                        R.drawable.trampoline3d_gauche,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);
                Mat rgba_right = Utils.loadResource(MainActivity.this, Utils.loadResource(
                        MainActivity.this, 
                        R.drawable.trampoline3d_droite,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);

                // create matrix with 1 channel
                Mat mleft= new Mat(rgba_left.size(), CvType.CV_8UC1);
                Mat mright= new Mat(rgba_right.size(), CvType.CV_8UC1);
                Mat mdisparity= new Mat(rgba_left.size(), CvType.CV_8UC1);

                // convert images to gray scale
                Imgproc.cvtColor(rgba_left, mleft, Imgproc.COLOR_BGR2GRAY);
                Imgproc.cvtColor(rgba_right, mright, Imgproc.COLOR_BGR2GRAY);

                StereoBM stereo = StereoBM.create(16*5, 21);
                stereo.setPreFilterSize(5);
                stereo.setPreFilterCap(61);
                stereo.setMinDisparity(-10);
                stereo.setNumDisparities(16*5);
                stereo.setTextureThreshold(300);
                stereo.setUniquenessRatio(5);
                stereo.setSpeckleWindowSize(0);
                stereo.setSpeckleRange(8);

                stereo.compute(mleft, mright, mdisparity);

                // normalize from float to bytes
                Core.normalize(mdisparity,rgba_right,0,255,Core.NORM_MINMAX,CvType.CV_8UC1);

                // display the result
                Imgproc.cvtColor(rgba_right, rgba_left, Imgproc.COLOR_GRAY2BGRA, 4);
                Imgproc.resize(rgba_left, rgba, rgba.size());

but I obtain poor result ...

left image : image description

right image : image description

result : image description

using StereoBM in java on Android

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web...

UPDATE : I wrote the following java code :

                // load left and right images
                Mat rgba_left = Utils.loadResource(
                        MainActivity.this, 
                        R.drawable.trampoline3d_gauche,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);
                Mat rgba_right = Utils.loadResource(
                        MainActivity.this, 
                        R.drawable.trampoline3d_droite,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);

                // create matrix with 1 channel
                Mat mleft= new Mat(rgba_left.size(), CvType.CV_8UC1);
                Mat mright= new Mat(rgba_right.size(), CvType.CV_8UC1);
                Mat mdisparity= new Mat(rgba_left.size(), CvType.CV_8UC1);

                // convert images to gray scale
                Imgproc.cvtColor(rgba_left, mleft, Imgproc.COLOR_BGR2GRAY);
                Imgproc.cvtColor(rgba_right, mright, Imgproc.COLOR_BGR2GRAY);

                StereoBM stereo = StereoBM.create(16*5, 21);
                stereo.setPreFilterSize(5);
                stereo.setPreFilterCap(61);
                stereo.setMinDisparity(-10);
                stereo.setNumDisparities(16*5);
                stereo.setTextureThreshold(300);
                stereo.setUniquenessRatio(5);
                stereo.setSpeckleWindowSize(0);
                stereo.setSpeckleRange(8);

                stereo.compute(mleft, mright, mdisparity);

                // normalize from float to bytes
                Core.normalize(mdisparity,rgba_right,0,255,Core.NORM_MINMAX,CvType.CV_8UC1);

                // display the result
                Imgproc.cvtColor(rgba_right, rgba_left, Imgproc.COLOR_GRAY2BGRA, 4);
                Imgproc.resize(rgba_left, rgba, rgba.size());

but I obtain poor result ...

left image : image description

right image : image description

result : image description

using StereoBM in java on AndroidAndroid -> some results

Hello is someone could give me an example to show how to use org.opencv.calib3d.StereoBM in Java (on Android in my case) ? I only found examples in C++ and Python on the web...

UPDATE EDIT2 : I tried to calibrate one camera before trying to calibrate both. So I wrote the following java code :

init variables :

        imageCorners = new MatOfPoint2f();
        savedImage = new Mat();
        imagePoints = new ArrayList<>();
        objectPoints = new ArrayList<>();
        intrinsic = new Mat(3, 3, CvType.CV_32FC1);
        distCoeffs = new Mat();
        boardSize = new Size(numCornersHor, numCornersVer);
        obj = new MatOfPoint3f();
        for (int j = 0; j < numSquares; j++)
            obj.push_back(new MatOfPoint3f(new Point3(j / numCornersHor, j % numCornersVer, 0.0f)));

In the main loop :

                if (!isCalibrated) {
                    if (touch_screen_down) {
                        Mat grayImage = new Mat(rgba.size(), CvType.CV_8UC1);
                        Imgproc.cvtColor(rgba, grayImage, Imgproc.COLOR_BGR2GRAY);

                        boolean found = Calib3d.findChessboardCorners(
                                grayImage, boardSize, imageCorners,
                                Calib3d.CALIB_CB_ADAPTIVE_THRESH + Calib3d.CALIB_CB_NORMALIZE_IMAGE + Calib3d.CALIB_CB_FAST_CHECK);

                        if (found && successes <= boardsNumber) {
                            // optimization
                            TermCriteria term = new TermCriteria(TermCriteria.EPS | TermCriteria.MAX_ITER, 30, 0.001);
                            Imgproc.cornerSubPix(grayImage, imageCorners,
                                    new Size(11, 11), new Size(-1, -1), term);

                            // save the current frame for further elaborations
                            grayImage.copyTo(savedImage);

                            // show the chessboard inner corners on screen
                            Calib3d.drawChessboardCorners(rgba, boardSize,
                                    imageCorners, found);

                            imagePoints.add(imageCorners);
                            imageCorners = new MatOfPoint2f();
                            objectPoints.add(obj);
                            successes++;
                        }

                        if (successes == boardsNumber) {
                            List<Mat> rvecs = new ArrayList<>();
                            List<Mat> tvecs = new ArrayList<>();
                            intrinsic.put(0, 0, 1);
                            intrinsic.put(1, 1, 1);

                            calib_error = Calib3d.calibrateCamera(objectPoints, imagePoints, savedImage.size(), intrinsic, distCoeffs, rvecs, tvecs);
                            isCalibrated = true;
                        }
                    }
                }
                else {   // is already calibrated so undistord the picture
                    Mat undistored = new Mat();
                    Imgproc.undistort(rgba, undistored, intrinsic, distCoeffs);
                    undistored.copyTo(rgba);
                }

BUT the calibration error (calib_error) is bad when I run this code with 20 pictures of a chessboard : values are between 150 and 200. I read that the calibration error should be less than 0.5 !! And when calibration is done, news pictures from my camera are very distorded... What is the problem ?

EDIT1 : I wrote the following java code :

                // load left and right images
                Mat rgba_left = Utils.loadResource(
                        MainActivity.this, 
                        R.drawable.trampoline3d_gauche,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);
                Mat rgba_right = Utils.loadResource(
                        MainActivity.this, 
                        R.drawable.trampoline3d_droite,
                        Imgcodecs.CV_LOAD_IMAGE_COLOR);

                // create matrix with 1 channel
                Mat mleft= new Mat(rgba_left.size(), CvType.CV_8UC1);
                Mat mright= new Mat(rgba_right.size(), CvType.CV_8UC1);
                Mat mdisparity= new Mat(rgba_left.size(), CvType.CV_8UC1);

                // convert images to gray scale
                Imgproc.cvtColor(rgba_left, mleft, Imgproc.COLOR_BGR2GRAY);
                Imgproc.cvtColor(rgba_right, mright, Imgproc.COLOR_BGR2GRAY);

                StereoBM stereo = StereoBM.create(16*5, 21);
                stereo.setPreFilterSize(5);
                stereo.setPreFilterCap(61);
                stereo.setMinDisparity(-10);
                stereo.setNumDisparities(16*5);
                stereo.setTextureThreshold(300);
                stereo.setUniquenessRatio(5);
                stereo.setSpeckleWindowSize(0);
                stereo.setSpeckleRange(8);

                stereo.compute(mleft, mright, mdisparity);

                // normalize from float to bytes
                Core.normalize(mdisparity,rgba_right,0,255,Core.NORM_MINMAX,CvType.CV_8UC1);

                // display the result
                Imgproc.cvtColor(rgba_right, rgba_left, Imgproc.COLOR_GRAY2BGRA, 4);
                Imgproc.resize(rgba_left, rgba, rgba.size());

but I obtain poor result ...

left image : image description

right image : image description

result : image description

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