[FIXED] OpenCV : Contour Detection Android contourldx problems

Issue

I am able to detect the Contour in an image using C++. However, I want to convert it in Android using java lang. So, i make it using android studio. (partly because I am a JAVA newbie)

Then i found some problems, When i run it, i had a error problems with this code :

if(contours[contourIdx].size()>100)

in this main program.

 @Override
    public void onCameraViewStarted(int width, int height) {
        mRgba = new Mat(height, width, CvType.CV_8UC4);
        mHsv = new Mat(height,width,CvType.CV_8UC3);
        hierarchy = new Mat();
        mHsvMask = new Mat();
        mDilated = new Mat(height, width, CvType.CV_8UC4);
    }
@Override
public void onCameraViewStopped() {
    mRgba.release();
    mHsv.release();
    mHsvMask.release();
    mDilated.release();
    hierarchy.release();

}

@Override
public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
    mRgba =inputFrame.rgba();
    mHsv = new Mat();

    Imgproc.cvtColor(mRgba, mHsv, Imgproc.COLOR_RGB2HSV, 3);
    hierarchy.release();
    Scalar lowerThreshold = new Scalar ( 120, 100, 100 ); 
    Scalar upperThreshold = new Scalar ( 179, 255, 255 ); 
    Core.inRange ( mHsv, lowerThreshold , upperThreshold, mHsvMask );

    Imgproc.dilate ( mHsvMask, mDilated, new Mat() );
    Imgproc.findContours(mDilated, contours, hierarchy, Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE);

    for ( int contourIdx=0; contourIdx < contours.size(); contourIdx++ )
    {
        if(contours[contourIdx].size()>100)  // Minimum size allowed for consideration
        {
            Imgproc.drawContours ( mRgba, contours, contourIdx, new Scalar(0,255,0) , -5);
        }
    }
    return mRgba;
}
}

Hopefully, someone has some experience in this. Thanks..

Solution

Use the area concept

 if(Imgproc.contourArea(contours.get(contourIdx))>100) {
             Imgproc.drawContours(mRgba, contours, contourIdx, new Scalar(Math.random() * 255, Math.random() * 255, Math.random() * 255), 1, 8, hierarchy, 0, new Point());
         }

Answered By - user5766922
Answer Checked By - Marie Seifert (JavaFixing Admin)