Solving native open cv code error in androd.mk for developing panorama on android

I am trying to develop an android application for generating panoramic images usig feature of image stitching in Open CV.

I have used the code give on the site given below.

http://ramsrigoutham.com/2012/12/21/panorama-app-on-android-using-stitching-module-opencv/

There is an error shown in the log cat shown below. Please guide me how to solve the error.

This is the screenshot of the native.cpp file where using namespace errors are shown in the image link given above

Android.mk file screenshot is given in the image link given above.

http://i.imgur.com/Hm8gtiY.png

This is the Native call for stitching images.

native.cpp

#include < jni.h >
#include <opencv2/core/core.hpp>
#include <opencv2/features2d/features2d.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/calib3d/calib3d.hpp>
#include <opencv2/stitching/stitcher.hpp>

#include < vector >
#include < iostream >
#include < stdio.h >
#include < list >
#include< sstream >
#include< string >

using namespace std;
using namespace cv;

extern "C" {
//JNIEXPORT Mat JNICALL Java_org_opencv_samples_tutorial3_Sample3Native_FindFeatures(JNIEnv*, jobject, jlong addrGray, jlong addrRgba)

JNIEXPORT void JNICALL Java_org_opencv_samples_tutorial3_Sample3Native_FindFeatures(
        JNIEnv*, jobject, jlong im1, jlong im2, jlong im3, jint no_images) {

    vector < Mat > imgs;
    bool try_use_gpu = false;
    // New testing
    Mat& temp1 = *((Mat*) im1);
    Mat& temp2 = *((Mat*) im2);
    Mat& pano = *((Mat*) im3);

    for (int k = 0; k < no_images; ++k) {
        string id;
        ostringstream convert;
        convert << k;
        id = convert.str();
        Mat img = imread("/storage/emulated/0/panoTmpImage/im" + id + ".jpeg");

        imgs.push_back(img);
    }

    Stitcher stitcher = Stitcher::createDefault(try_use_gpu);
    Stitcher::Status status = stitcher.stitch(imgs, pano);

}

}

This is the android.mk file which i have created having no idea on how to generate it.

Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

include ../../android-development/OpenCV-2.4.10-android-sdk/OpenCV-2.4.10-android-sdk/sdk/native/jni/OpenCV.mk

LOCAL_MODULE    := native_activity
LOCAL_SRC_FILES := native.cpp
LOCAL_LDLIBS    += -lm -llog -landroid
LOCAL_STATIC_LIBRARIES += android_native_app_glue

include $(BUILD_SHARED_LIBRARY)

$(call import-module,android/native_app_glue)

And this is the Main Android code that has main GUI and calls the OpenCV function

Sample3Native.java

package org.opencv.samples.tutorial3;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener;
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.highgui.Highgui;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;

public class Sample3Native extends Activity implements CvCameraViewListener {
    private static final String TAG = "OCVSample::Activity";

    public static final int VIEW_MODE_RGBA = 0;
    public static final int SAVE_IMAGE_MAT = 1;
    public static final int CAPT_STILL_IM = 2;
    private static int viewMode = VIEW_MODE_RGBA;
//  public static int image_count = 0;
    private MenuItem mStitch;
    private MenuItem mItemCaptureImage;
    private Mat mRgba;
    private Mat mGrayMat;
    private Mat panorama;
    private Mat mtemp;
    private List < Mat > images_to_be_stitched = new ArrayList < Mat >();
    private CameraBridgeViewBase mOpenCvCameraView;
    private long mPrevTime = new Date().getTime();
    private static final int FRAME2GRAB = 10;
    private int mframeNum = 0;
    private static final File tempImageDir = new File(Environment.getExternalStorageDirectory() + File.separator + "panoTmpImage");
    private static final File StitchImageDir = new File(Environment.getExternalStorageDirectory()+ File.separator  + "panoStitchIm");
    private static final String mImageName = "im";
    private static final String mImageExt = ".jpeg";
    private long recordStart = new Date().getTime();
    private static final long MAX_VIDEO_INTERVAL_IN_SECONDS = 3 * 1000; // Convert milliseconds to seconds
    public final Handler mHandler = new Handler();

    // Create runnable for posting
    final Runnable mUpdateResults = new Runnable() {
        public void run() {
            updateResultsInUi();
        }
    };

    private void updateResultsInUi()
    {

    }

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

                // Load native library after(!) OpenCV initialization
                System.loadLibrary("native_sample");

                mOpenCvCameraView.enableView();
            }
                break;
            default: {
                super.onManagerConnected(status);
            }
                break;
            }
        }
    };

    public Sample3Native() {
        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);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

        setContentView(R.layout.tutorial3_surface_view);

        final Button btnVidCapt = (Button) findViewById(R.id.btnVidCapt);
        btnVidCapt.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                startVidCap();
            }
        });

        final Button btnStitch = (Button) findViewById(R.id.btnStitch);
        btnStitch.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                stitchImages();
            }
        });

        final Button btnViewStitchedIm = (Button) findViewById(R.id.btnViewStitchedIm);
        btnViewStitchedIm.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                viewStitchImages();
            }
        });

        final Button btnCapStil = (Button) findViewById(R.id.btnCapStil);
        btnCapStil.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                captStillImage();
            }
        });
        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial4_activity_surface_view);
        mOpenCvCameraView.setCvCameraViewListener(this);
    }

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

    @Override
    public void onResume() {
        super.onResume();
        OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this,
                mLoaderCallback);
    }

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

    public void onCameraViewStarted(int width, int height) {
        mRgba = new Mat(height, width, CvType.CV_8UC3);
        mGrayMat = new Mat(height, width, CvType.CV_8UC1);
        mtemp = new Mat(height, width, CvType.CV_8UC3);
        panorama = new Mat(height, width, CvType.CV_8UC3);
    }

    public void onCameraViewStopped() {
        mRgba.release();
        mGrayMat.release();
        mtemp.release();
        panorama.release();
    }

    public Mat onCameraFrame(Mat inputFrame) {
        inputFrame.copyTo(mRgba);
        switch (Sample3Native.viewMode) {
        case Sample3Native.VIEW_MODE_RGBA: {
            Core.putText(mRgba, "Video Mode", new Point(10, 50), 3, 1, new Scalar(255, 0, 0, 255), 2);
            // Update start recordtime until starting recording
        }break;
        case Sample3Native.SAVE_IMAGE_MAT: {
            long curTime = new Date().getTime();
            Core.putText(mRgba, "Record Mode", new Point(10, 50), 3, 1, new Scalar(255, 0, 0, 255), 2);
            long timeDiff = curTime - recordStart;
            Log.i("timeDiff", Long.toString(timeDiff));

            if ( timeDiff < MAX_VIDEO_INTERVAL_IN_SECONDS) {
                if ((mframeNum % FRAME2GRAB) == 0) {
                    saveImageToArray(inputFrame);
                    mframeNum++;
                }
                else
                    mframeNum++;
            }
            else
            {
                mframeNum = 0;
                turnOffCapture();
            }
        }break;
        case Sample3Native.CAPT_STILL_IM :
        {
            saveImageToArray(inputFrame);
            Sample3Native.viewMode = Sample3Native.VIEW_MODE_RGBA;
        }
        }
        return mRgba;
    }

    public void startVidCap() {
        if (Sample3Native.viewMode == Sample3Native.VIEW_MODE_RGBA)
        {
            turnOnCapture();
        }
        else if (Sample3Native.viewMode == Sample3Native.SAVE_IMAGE_MAT)
        {
            turnOffCapture();
        }
    }

    private void turnOffCapture()
    {

        Sample3Native.viewMode = Sample3Native.VIEW_MODE_RGBA;
    }

    private void turnOnCapture()
    {

        Sample3Native.viewMode = Sample3Native.SAVE_IMAGE_MAT;
//      startVidCapture.setText("Stop Video Capture");
        images_to_be_stitched.clear();
        recordStart = new Date().getTime();

    }

    public void stitchImages() {
        if(!images_to_be_stitched.isEmpty())
        {
            for (int j = 0; j < images_to_be_stitched.size(); j++) {
                writeImage(images_to_be_stitched.get(j), j);
            }
        Log.i("stitchImages", "Done writing 2 disk. Starting stitching " + images_to_be_stitched.size() + " images");
            FindFeatures(images_to_be_stitched.get(0).getNativeObjAddr(),
                    images_to_be_stitched.get(0).getNativeObjAddr(),
                    panorama.getNativeObjAddr(), images_to_be_stitched.size());
        Log.i("stitchImages", "Done stitching. Writing panarama");
            writePano(panorama);

        Log.i("stitchImages", "deleting temp files");

            deleteTmpIm();
        }
    }

    public void captStillImage()
    {
        Sample3Native.viewMode = Sample3Native.CAPT_STILL_IM;

    }

    private String getFullFileName( int num)
    {
        return mImageName + num + mImageExt;
    }

    private void writeImage(Mat image, int imNum)
    {
        writeImage(image, getFullFileName(imNum));
    }

    private void writeImage(Mat image, String fileName) {
        File createDir = tempImageDir;
        if(!createDir.exists())
            createDir.mkdir();
        Highgui.imwrite(tempImageDir+File.separator + fileName, image);
    }

    private void writePano(Mat image)
    {
        Date dateNow = new  Date();
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd_HHmmss");
        if(!StitchImageDir.exists())
            StitchImageDir.mkdir();
        Highgui.imwrite(StitchImageDir.getPath()+ File.separator + "panoStich"+dateFormat.format(dateNow) +mImageExt, image);

    }

    private void deleteTmpIm()
    {
        File curFile;
        for (int j = 0; j < images_to_be_stitched.size(); j++) {
            curFile = new File(getFullFileName(j));
            curFile.delete();
        }
        images_to_be_stitched.clear();
    }

    public void viewStitchImages()
    {

        Intent intent = new Intent(this, GalleryActivity.class);

        startActivity(intent);
    }

    private void saveImageToArray(Mat inputFrame) {
        images_to_be_stitched.add(inputFrame.clone());
    }

    private int FPS() {
        long curTime = new Date().getTime();
        int FPS = (int) (1000 / (curTime - mPrevTime));
        mPrevTime = curTime;
        return FPS;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return true;

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
    return true;
    }

    // public native void FindFeatures(List pano_images, Long stitch );
    public native void FindFeatures(long image1, long image2, long image3,
            int count);
}

Answer

I was going to ask you to show us your Application.mk file, but since I don’t have enough rep I can’t comment your question, however, I was able to reproduce your problem by deleting some lines of my working project Application.mk, so try adjusting your Application.mk to something like this:

APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
APP_PLATFORM := android-16