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I followed the color-blob-detection technique sample from opencv android sdk.

For the time being i was able to select a object from the live camera frame and then opencv actually marks the object but what i noticed it also detects the objects with same color.

I just want to select the object that i just touched. How to mark that only selected region.

ColorBlobDetectionActivity

public boolean onTouch(View v, MotionEvent event) {
        int cols = mRgba.cols();
        int rows = mRgba.rows();

        int xOffset = (mOpenCvCameraView.getWidth() - cols) / 2;
        int yOffset = (mOpenCvCameraView.getHeight() - rows) / 2;

        int x = (int)event.getX() - xOffset;
        int y = (int)event.getY() - yOffset;

        Log.i(TAG, "Touch image coordinates: (" + x + ", " + y + ")");

        if ((x < 0) || (y < 0) || (x > cols) || (y > rows)) return false;

        Rect touchedRect = new Rect();

        touchedRect.x = (x>4) ? x-4 : 0;
        touchedRect.y = (y>4) ? y-4 : 0;

        touchedRect.width = (x+4 < cols) ? x + 4 - touchedRect.x : cols - touchedRect.x;
        touchedRect.height = (y+4 < rows) ? y + 4 - touchedRect.y : rows - touchedRect.y;


        Mat touchedRegionRgba = mRgba.submat(touchedRect);


        Mat touchedRegionHsv = new Mat();
        Imgproc.cvtColor(touchedRegionRgba, touchedRegionHsv, Imgproc.COLOR_RGB2HSV_FULL);

        // Calculate average color of touched region
        mBlobColorHsv = Core.sumElems(touchedRegionHsv);
        int pointCount = touchedRect.width*touchedRect.height;
        for (int i = 0; i < mBlobColorHsv.val.length; i++)
            mBlobColorHsv.val[i] /= pointCount;

        Toast.makeText(ColorBlobDetectionActivity.this,"HSV = "+mBlobColorHsv,Toast.LENGTH_LONG).show();

        mBlobColorRgba = converScalarHsv2Rgba(mBlobColorHsv);

        Log.i(TAG, "Touched rgba color: (" + mBlobColorRgba.val[0] + ", " + mBlobColorRgba.val[1] +
                ", " + mBlobColorRgba.val[2] + ", " + mBlobColorRgba.val[3] + ")");

        mDetector.setHsvColor(mBlobColorHsv);

        Imgproc.resize(mDetector.getSpectrum(), mSpectrum, SPECTRUM_SIZE);

        mIsColorSelected = true;

        touchedRegionRgba.release();
        touchedRegionHsv.release();

        return false; // don't need subsequent touch events
    }

    public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
        mRgba = inputFrame.rgba();

        if (mIsColorSelected) {
            mDetector.process(mRgba);
            List<MatOfPoint> contours = mDetector.getContours();
            Log.e(TAG, "Contours count: " + contours.size());
            Imgproc.drawContours(mRgba, contours, -1, CONTOUR_COLOR);

            Mat colorLabel = mRgba.submat(4, 68, 4, 68);
            colorLabel.setTo(mBlobColorRgba);

            Mat spectrumLabel = mRgba.submat(4, 4 + mSpectrum.rows(), 70, 70 + mSpectrum.cols());
            mSpectrum.copyTo(spectrumLabel);
        }

        return mRgba;
    }

    private Scalar converScalarHsv2Rgba(Scalar hsvColor) {
        Mat pointMatRgba = new Mat();
        Mat pointMatHsv = new Mat(1, 1, CvType.CV_8UC3, hsvColor);
        Imgproc.cvtColor(pointMatHsv, pointMatRgba, Imgproc.COLOR_HSV2RGB_FULL, 4);

        return new Scalar(pointMatRgba.get(0, 0));
    }