qadirsuh's profile - activity

First I really appreciate the the blog http://opencv-code.com/tutorials/auto...

I'm following this, but I'm not processing the image (Used in the blog above) but, rather I,m trying to detect the paper sheet of any size (A4, legal or any normal rectangular paper size) in real time camera preview.

Problem Im getting is After "Expanding the hough line segments to fit the image" Im getting large number of hough lines hence getting more than 4 intersecting points (not == 4)

like this http://s17.postimg.org/i0a57fb8v/devi...

How can I remove the rest invalid points, I just need the 4 corners points,

Please Help me in this regard

Im using OpenCV Library for Android

please mainly focus on detectPaperSheet() method :)

here is my code

package org.opencv.samples.tutorial1;

import java.util.ArrayList;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.Point;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.imgproc.Imgproc;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SurfaceView;
import android.view.WindowManager;
import android.widget.Toast;

public class Tutorial1Activity extends Activity implements
        CvCameraViewListener2 {
    private static final String TAG = "OCVSample::Activity";

private CameraBridgeViewBase mOpenCvCameraView;
private boolean mIsJavaCamera = true;
private MenuItem mItemSwitchCamera = null;

private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
    @Override
    public void onManagerConnected(int status) {
        switch (status) {
        case LoaderCallbackInterface.SUCCESS: {
            Log.i(TAG, "OpenCV loaded successfully");
            mOpenCvCameraView.enableView();
        }
            break;
        default: {
            super.onManagerConnected(status);
        }
            break;
        }
    }
};

public Tutorial1Activity() {
    Log.i(TAG, "Instantiated new " + this.getClass());
}

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    Log.i(TAG, "called onCreate");
    super.onCreate(savedInstanceState);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

    setContentView(R.layout.tutorial1_surface_view);

    if (mIsJavaCamera)
        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_java_surface_view);
    else
        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_native_surface_view);

    mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);

    mOpenCvCameraView.setCvCameraViewListener(this);
}

@Override
public void onPause() {
    super.onPause();
    if (mOpenCvCameraView != null)
        mOpenCvCameraView.disableView();
}

@Override
public void onResume() {
    super.onResume();
    OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_9, this,
            mLoaderCallback);
}

public void onDestroy() {
    super.onDestroy();
    if (mOpenCvCameraView != null)
        mOpenCvCameraView.disableView();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    Log.i(TAG, "called onCreateOptionsMenu");
    mItemSwitchCamera = menu.add("Toggle Native/Java camera");
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    String toastMesage = new String();
    Log.i(TAG, "called onOptionsItemSelected; selected item: " + item);

    if (item == mItemSwitchCamera) {
        mOpenCvCameraView.setVisibility(SurfaceView.GONE);
        mIsJavaCamera = !mIsJavaCamera;

        if (mIsJavaCamera) {
            mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_java_surface_view);
            toastMesage = "Java Camera";
        } else {
            mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_native_surface_view);
            toastMesage = "Native Camera";
        }

        mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
        mOpenCvCameraView.setCvCameraViewListener(this);
        mOpenCvCameraView.enableView();
        Toast toast = Toast.makeText(this, toastMesage, Toast.LENGTH_LONG);
        toast.show();
    }

    return true;
}

public void onCameraViewStarted(int width, int height) {
}

public void onCameraViewStopped() {
}

public Mat onCameraFrame(CvCameraViewFrame inputFrame) {

    return detectPaperSheet(inputFrame.rgba());

}

private Mat detectPaperSheet(Mat original_image ...