Example usage for org.opencv.imgproc Imgproc threshold

List of usage examples for org.opencv.imgproc Imgproc threshold

Introduction

In this page you can find the example usage for org.opencv.imgproc Imgproc threshold.

Prototype

public static double threshold(Mat src, Mat dst, double thresh, double maxval, int type) 

Source Link

Usage

From source file:de.hftl_projekt.ict.MainActivity.java

/**
 * method to reduce the color (quantize) the given matrix (image)
 * @param image input matrix/* w ww.ja  v  a  2 s  . c  o  m*/
 * @return modified input matrix
 */
public Mat reduceColors(Mat image) {
    if (channels.size() == 0) {
        for (int i = 0; i < image.channels(); i++) {
            Mat channel = new Mat(); // fill array with a matrix for each channel
            channels.add(channel);
        }

    }
    int i = 0;
    // process each channel individually
    for (Mat c : channels) {
        Core.extractChannel(image, c, i);
        // binary quantization (set threshold so each color (R, G, B) can have the value (0 or 255) )
        // and using the Otsu algorithm to optimize the quantization
        Imgproc.threshold(c, c, 0, 255, Imgproc.THRESH_BINARY_INV + Imgproc.THRESH_OTSU);
        i++;
    }
    Core.merge(channels, image); // put the channel back together
    return image;
}

From source file:detectiontest.ParticleDetector.java

/**
 * Particle detection algorithm./*from  w  w  w. j av  a2  s  .  c o m*/
 * 
 * @param image an image where we want to detect
 * @return list of detected particles
 */
public static List<Particle> detect(Mat image) {

    // blur the image to denoise
    Imgproc.blur(image, image, new Size(3, 3));

    // thresholds the image
    Mat thresholded = new Mat();
    Imgproc.threshold(image, thresholded, THRESHOLD, MAX, Imgproc.THRESH_TOZERO_INV);

    // detect contours
    List<MatOfPoint> contours = new ArrayList<>();
    Imgproc.findContours(thresholded, contours, new Mat(), Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE,
            ORIGIN);

    // create particle from each contour
    List<Particle> particles = new ArrayList<>();
    for (MatOfPoint contour : contours) {
        particles.add(new Particle(contour));
    }

    return particles;
}

From source file:edu.fiu.cate.breader.BaseSegmentation.java

/**
 * Finds the bounding box for the book on the stand using 
 * the high resolution image.//from w w  w  .  j  a va2 s  .co m
 * @param src- High Resolution image of the book
 * @return Rectangle delineating the book
 */
public Rect highRes(Mat src) {
    Mat dst = src.clone();
    Imgproc.blur(src, dst, new Size(100.0, 100.0), new Point(-1, -1), Core.BORDER_REPLICATE);
    Imgproc.threshold(dst, dst, 0, 255, Imgproc.THRESH_BINARY_INV + Imgproc.THRESH_OTSU);
    Imgproc.Canny(dst, dst, 50, 200, 3, false);

    List<MatOfPoint> contours = new LinkedList<>();
    Mat hierarchy = new Mat();
    Imgproc.findContours(dst, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE,
            new Point(0, 0));

    Mat color = new Mat();
    Imgproc.cvtColor(src, color, Imgproc.COLOR_GRAY2BGR);
    for (int k = 0; k < contours.size(); k++) {
        byte[] vals = ITools.getHeatMapColor((float) k / (float) contours.size());
        Imgproc.drawContours(color, contours, k, new Scalar(vals[0], vals[1], vals[2]), 8);
    }
    new IViewer("HighRes Contours ", BReaderTools.bufferedImageFromMat(color));

    Point center = new Point(src.cols() / 2, src.rows() / 2);
    //Check hierarchy tree
    int[] res = polySearch(center, hierarchy, contours, 0);
    while (res[0] != 1 && res[2] != -1) {
        res = polySearch(center, hierarchy, contours, res[2]);
        if (res[0] == 1)
            break;
    }

    MatOfInt tHull = new MatOfInt();
    int index = 0;
    if (res[1] != -1) {
        index = res[1];
    }
    Imgproc.convexHull(contours.get(index), tHull);

    //get bounding box
    MatOfPoint cont = contours.get(index);
    Point[] points = new Point[tHull.rows()];
    for (int i = 0; i < tHull.rows(); i++) {
        int pIndex = (int) tHull.get(i, 0)[0];
        points[i] = new Point(cont.get(pIndex, 0));
    }
    Rect out = Imgproc.boundingRect(new MatOfPoint(points));
    return out;
}

From source file:edu.ucue.tfc.Modelo.VideoProcessor.java

/**
* Processes {@code firstFrame} and {@code secondFrame}.
* @param firstFrame    the first frame of a cycle.
*///from w ww.  j  ava2 s .  c o  m
private void processFrame(Mat firstFrame) {
    double contourArea = 0;
    int position = 0;
    try {
        /**
         * Redimensiona el el cuadro actual
         *
         */
        Imgproc.resize(firstFrame, firstFrame, frameSize);

        /**
         * Convierte el cuadro por segundo a escala de grises
         */
        Imgproc.cvtColor(firstFrame, firstGrayImage, Imgproc.COLOR_BGR2GRAY);

        /**
         * Lee el siguiente cuadro, lo redimensiona y convierte a escala de grises
         */
        video.read(secondFrame);

        Imgproc.resize(secondFrame, secondFrame, frameSize);

        Imgproc.cvtColor(secondFrame, secondGrayImage, Imgproc.COLOR_BGR2GRAY);

        /**
         * Obtiene la diferencia absoluta por pixel de los cuadros anteriores.
         */
        Core.absdiff(firstGrayImage, secondGrayImage, differenceOfImages);
        Imgproc.threshold(differenceOfImages, thresholdImage, 25, 255, Imgproc.THRESH_BINARY);
        Imgproc.blur(thresholdImage, thresholdImage, new Size(12, 12));
        Imgproc.threshold(thresholdImage, thresholdImage, 20, 255, Imgproc.THRESH_BINARY);
        /////
        for (int i = 0; i < contours.size(); ++i) {
            contours.get(i).release();
        }
        contours.clear();

        /**
         * La linea Horizontal
         */
        Imgproc.line(firstFrame, controlPoints.get(6), controlPoints.get(7), new Scalar(255, 0, 0),
                Imgproc.LINE_4);
        Imgproc.findContours(thresholdImage, contours, hierarchy, Imgproc.RETR_TREE,
                Imgproc.CHAIN_APPROX_SIMPLE);

        for (int i = 0; i < hullPoints.size(); ++i) {
            hullPoints.get(i).release();
        }
        hullPoints.clear();

        for (int i = 0; i < contours.size(); i++) {
            MatOfInt tmp = new MatOfInt();
            Imgproc.convexHull(contours.get(i), tmp, false);
            hullPoints.add(tmp);
        }

        /**
         * Busca el contorno con el rea ms grande
         */
        if (contours.size() > 0) {
            for (int i = 0; i < contours.size(); i++) {
                if (Imgproc.contourArea(contours.get(i)) > contourArea) {
                    contourArea = Imgproc.contourArea(contours.get(i));
                    position = i;
                    boundingRectangle = Imgproc.boundingRect(contours.get(i));
                }

            }
        }
        secondFrame.release();
        hierarchy.release();
        secondGrayImage.release();
        firstGrayImage.release();
        thresholdImage.release();
        differenceOfImages.release();
    } catch (Exception e) {
        System.out.println(e.getMessage());
    }

    if (controlPoints.get(6).inside(boundingRectangle)) {
        Imgproc.line(frame, controlPoints.get(0), controlPoints.get(1), new Scalar(0, 0, 255), 2);
        wasAtLeftPoint = true;
    } else if (!controlPoints.get(6).inside(boundingRectangle)) {
        Imgproc.line(frame, controlPoints.get(0), controlPoints.get(1), new Scalar(0, 255, 0), 2);
    }

    if (controlPoints.get(8).inside(boundingRectangle)) {
        Imgproc.line(frame, controlPoints.get(2), controlPoints.get(3), new Scalar(0, 0, 255), 2);
        wasAtCenterPoint = true;
    } else if (!controlPoints.get(8).inside(boundingRectangle)) {
        Imgproc.line(frame, controlPoints.get(2), controlPoints.get(3), new Scalar(0, 255, 0), 2);
    }

    if (controlPoints.get(7).inside(boundingRectangle)) {
        Imgproc.line(frame, controlPoints.get(4), controlPoints.get(5), new Scalar(0, 0, 255), 2);
        wasAtRightPoint = true;
    } else if (!controlPoints.get(7).inside(boundingRectangle)) {
        Imgproc.line(frame, controlPoints.get(4), controlPoints.get(5), new Scalar(0, 255, 0), 2);
    }

    if (wasAtCenterPoint && wasAtLeftPoint && wasAtRightPoint) {
        detectedCarsCount++;
        wasDetected = true;
        wasAtCenterPoint = false;
        wasAtLeftPoint = false;
        wasAtRightPoint = false;
    }

    if (contourArea > 3000) {
        Imgproc.drawContours(frame, contours, position, new Scalar(255, 255, 255));
    }
}

From source file:fi.conf.tabare.ARDataProvider.java

private void detect() {

    //Mat composite_image;
    Mat input_image = new Mat();
    Mat undistorted_image = new Mat();
    Mat circles = new Mat();
    MatOfKeyPoint mokp = new MatOfKeyPoint();
    Mat cameraMatrix = null;//  w  w w  .  j  av  a 2s.c  om

    //List<Mat> channels = new LinkedList<>();

    //Loop
    while (running) {
        try {
            if (inputVideo.read(input_image)) {
                Mat preview_image = null;

                if (selectedView == View.calib)
                    preview_image = input_image.clone();

                //Imgproc.cvtColor(input_image, input_image, Imgproc.COLOR_RGB2HSV);
                //Core.split(input_image, channels);

                Imgproc.cvtColor(input_image, input_image, Imgproc.COLOR_BGR2GRAY);

                //Imgproc.equalizeHist(input_image, input_image);

                input_image.convertTo(input_image, -1, params.contrast, params.brightness); //image*contrast[1.0-3.0] + brightness[0-255]

                doBlur(input_image, input_image, params.blur, params.blurAmount);

                if (selectedView == View.raw)
                    preview_image = input_image.clone();

                if (params.enableDistortion) {

                    if (cameraMatrix == null)
                        cameraMatrix = Imgproc.getDefaultNewCameraMatrix(Mat.eye(3, 3, CvType.CV_64F),
                                new Size(input_image.width(), input_image.height()), true);

                    Imgproc.warpAffine(input_image, input_image, shiftMat, frameSize);

                    if (undistorted_image == null)
                        undistorted_image = new Mat((int) frameSize.width * 2, (int) frameSize.height * 2,
                                CvType.CV_64F);

                    Imgproc.undistort(input_image, undistorted_image, cameraMatrix, distCoeffs);

                    input_image = undistorted_image.clone();

                    if (selectedView == View.dist)
                        preview_image = input_image.clone();

                }

                //               if(background == null) background = input_image.clone();         
                //               if(recaptureBg){
                //                  backgSubstractor.apply(background, background);
                //                  System.out.println(background.channels() + " " + background.size() );
                //                  System.out.println(input_image.channels() + " " + input_image.size() );
                //                  recaptureBg = false;
                //               }
                //               if(dynamicBGRemoval){
                //                  //Imgproc.accumulateWeighted(input_image, background, dynamicBGAmount);
                //                  //Imgproc.accumulateWeighted(input_image, background, 1.0f);
                //                  //Core.subtract(input_image, background, input_image);
                //                  //Core.bitwise_xor(input_image, background, input_image);
                //
                //                  doBlur(input_image, background, Blur.normal_7x7, 0); //Blur a little, to get nicer result when substracting
                //                  backgSubstractor.apply(background, background, dynamicBGAmount);
                //               }
                //               if(background != null) Core.add(input_image, background, input_image);

                if (params.blobTracking) {
                    Mat blobs_image = input_image.clone();

                    Imgproc.threshold(blobs_image, blobs_image, params.blobThreshold, 254,
                            (params.blobThInverted ? Imgproc.THRESH_BINARY_INV : Imgproc.THRESH_BINARY));

                    Size kernelSize = null;

                    switch (params.blobMorpthKernelSize) {
                    case size_3x3:
                        kernelSize = new Size(3, 3);
                        break;
                    case size_5x5:
                        kernelSize = new Size(5, 5);
                        break;
                    case size_7x7:
                        kernelSize = new Size(7, 7);
                        break;
                    case size_9x9:
                        kernelSize = new Size(9, 9);
                        break;
                    }

                    int kernelType = -1;

                    switch (params.blobMorphKernelShape) {
                    case ellipse:
                        kernelType = Imgproc.MORPH_ELLIPSE;
                        break;
                    case rect:
                        kernelType = Imgproc.MORPH_RECT;
                        break;
                    default:
                        break;
                    }

                    switch (params.blobMorphOps) {
                    case dilate:
                        Imgproc.dilate(blobs_image, blobs_image,
                                Imgproc.getStructuringElement(kernelType, kernelSize));
                        break;
                    case erode:
                        Imgproc.erode(blobs_image, blobs_image,
                                Imgproc.getStructuringElement(kernelType, kernelSize));
                        break;
                    default:
                        break;
                    }

                    if (blobFeatureDetector == null)
                        blobFeatureDetector = FeatureDetector.create(FeatureDetector.SIMPLEBLOB);

                    blobFeatureDetector.detect(blobs_image, mokp);
                    blobData.add(mokp);

                    if (selectedView == View.blob)
                        preview_image = blobs_image.clone();

                    blobs_image.release();
                }

                if (params.tripTracking) {

                    Mat trips_image = undistorted_image.clone();

                    if (params.tripEnableThresholding)
                        if (params.tripAdaptThreshold) {
                            Imgproc.adaptiveThreshold(trips_image, trips_image, 255,
                                    (params.tripThInverted ? Imgproc.THRESH_BINARY_INV : Imgproc.THRESH_BINARY),
                                    Imgproc.ADAPTIVE_THRESH_MEAN_C, 5, params.tripThreshold * 0.256f);
                        } else {
                            Imgproc.threshold(trips_image, trips_image, params.tripThreshold, 255,
                                    (params.tripThInverted ? Imgproc.THRESH_BINARY_INV
                                            : Imgproc.THRESH_BINARY));
                        }

                    switch (params.tripMorphOps) {
                    case dilate:
                        Imgproc.dilate(trips_image, trips_image,
                                Imgproc.getStructuringElement(Imgproc.MORPH_ELLIPSE, new Size(3, 3)));
                        break;
                    case erode:
                        Imgproc.erode(trips_image, trips_image,
                                Imgproc.getStructuringElement(Imgproc.MORPH_ELLIPSE, new Size(3, 3)));
                        break;
                    default:
                        break;
                    }

                    //Imgproc.HoughCircles(tres, circ, Imgproc.CV_HOUGH_GRADIENT, 1, tres.height()/8, 80, 1+p.par4, p.par5, p.par6);
                    Imgproc.HoughCircles(trips_image, circles, Imgproc.CV_HOUGH_GRADIENT, params.tripDP,
                            params.tripCenterDist, params.tripCannyThresh, params.tripAccumThresh,
                            params.tripRadMin, params.tripRadMax);

                    for (int i = 0; i < circles.cols(); i++) {

                        double[] coords = circles.get(0, i);

                        if (coords == null || coords[0] <= 1 || coords[1] <= 1)
                            continue; //If the circle is off the limits, or too small, don't process it.

                        TripcodeCandidateSample tc = new TripcodeCandidateSample(undistorted_image, coords);

                        if (tc.isValid())
                            tripcodeData.add(tc);

                    }

                    if (selectedView == View.trip)
                        preview_image = trips_image.clone();
                    trips_image.release();

                }

                if (preview_image != null) {
                    camPreviewPanel.updatePreviewImage(preview_image);
                    preview_image.release();
                }

            } else {
                System.out.println("frame/cam failiure!");
            }

        } catch (Exception e) {
            e.printStackTrace();
            running = false;
        }

        //FPS calculations
        if (camPreviewPanel != null) {
            long t = System.currentTimeMillis();
            detectTime = (t - lastFrameDetectTime);
            lastFrameDetectTime = t;
            camPreviewPanel.updateDetectTime(detectTime);
        }

    }

    //De-init
    circles.release();
    undistorted_image.release();
    input_image.release();
    inputVideo.release();
    shiftMat.release();
}

From source file:finalpro.FinalPro.java

public static String threshholding() {
    Mat destination = null;/*from w w  w  .j a  v  a  2  s.  c  om*/
    Mat source = null;
    String str = "";
    try {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        source = Imgcodecs.imread("C:/QuadPotroler/FinalPro/src/images/20151207_153915.jpg",
                Imgcodecs.CV_LOAD_IMAGE_COLOR);
        destination = new Mat(source.rows(), source.cols(), source.type());
        destination = source;
        Imgproc.threshold(source, destination, 127, 255, Imgproc.THRESH_TOZERO);
        Imgcodecs.imwrite("C:/QuadPotroler/FinalPro/src/images/threshdold.jpg", destination);
        str = "C:/QuadPotroler/FinalPro/src/images/threshdold.jpg";
    } catch (Exception e) {
        System.out.println("error: " + e.getMessage());
    }
    return str;
}

From source file:fuzzycv.MainFrame.java

private Mat removeBG(Mat frame) {

    Mat hsvImg = new Mat();
    List<Mat> hsvPlanes = new ArrayList<>();
    Mat thresholdImg = new Mat();

    //threshold the image with the histogram average value
    hsvImg.create(frame.size(), CvType.CV_8U);
    Imgproc.cvtColor(frame, hsvImg, Imgproc.COLOR_BGR2HSV);
    Core.split(hsvImg, hsvPlanes);// w w w . j a v  a2  s. c  om

    double threshValue = getHistoAvg(hsvImg, hsvPlanes.get(0));

    if (inverseCheckBox.isSelected()) {
        Imgproc.threshold(hsvPlanes.get(0), thresholdImg, threshValue, 179.0, Imgproc.THRESH_BINARY_INV);
    } else {
        Imgproc.threshold(hsvPlanes.get(0), thresholdImg, threshValue, 179.0, Imgproc.THRESH_BINARY);
    }

    Imgproc.blur(thresholdImg, thresholdImg, new Size(5, 5));

    // dilate to fill gaps, erode to smooth edges
    Imgproc.dilate(thresholdImg, thresholdImg, new Mat(), new Point(-1, 1), 6);
    Imgproc.erode(thresholdImg, thresholdImg, new Mat(), new Point(-1, 1), 6);

    Imgproc.threshold(thresholdImg, thresholdImg, threshValue, 179.0, Imgproc.THRESH_BINARY);

    // create the new image
    Mat foreground = new Mat(frame.size(), CvType.CV_8UC3, new Scalar(255, 255, 255));
    frame.copyTo(foreground, thresholdImg);

    return foreground;
}

From source file:gab.opencv.OpenCV.java

License:Open Source License

/**
 * Apply a global threshold to an image. Produces a binary image
 * with white pixels where the original image was above the threshold
 * and black where it was below.//from w  w  w. j  a  v a 2 s. c  o m
 * 
 * @param threshold
 *       An int from 0-255.
 */
public void threshold(int threshold) {
    Imgproc.threshold(getCurrentMat(), getCurrentMat(), threshold, 255, Imgproc.THRESH_BINARY);
}

From source file:gab.opencv.OpenCV.java

License:Open Source License

/**
 * Apply a global threshold to the image. The threshold is determined by Otsu's method, which
 * attempts to divide the image at a threshold which minimizes the variance of pixels in the black
 * and white regions.// www .j a va 2  s . c o  m
 *
 * See: https://en.wikipedia.org/wiki/Otsu's_method
 */
public void threshold() {
    Imgproc.threshold(getCurrentMat(), getCurrentMat(), 0, 255, Imgproc.THRESH_BINARY | Imgproc.THRESH_OTSU);
}

From source file:gab.opencv.OpenCVProcessingUtils.java

License:Open Source License

public void threshold(int threshold) {
    Imgproc.threshold(getCurrentMat(), getCurrentMat(), threshold, 255, Imgproc.THRESH_BINARY);
}