Android - Real-Time get image data from camera?

Question

I want to do some image processing jobs and I want to get real-time image data from my camera(during preview state) instead of after taking pictures.

I looked on this post but don't know how to use this.

After setting this,

SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback() 
{   
    public void surfaceCreated(SurfaceHolder holder) {
       camera.setPreviewCallback(previewCallback);
    }
}

and this

private Camera.PreviewCallback  previewCallback= new Camera.PreviewCallback()
{   
    @Override
    public void onPreviewFrame(byte[] data,Camera cam)
    {
            Camera.Size previewSize = cam.getParameters().getPreviewSize();
            YuvImage yuvImage = new YuvImage(data, ImageFormat.NV21,previewSize.width,previewSize.height, null);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            yuvImage.compressToJpeg(new Rect(0,0,previewSize.width,previewSize.height),80,baos);
            byte[] jdata = baos.toByteArray();
            Bitmap bitmap = BitmapFactory.decodeByteArray(jdata,0,jdata.length);    
    }
};

How can I real-time get my image data? Could anyone please kindly give me an short example code?

Thanks

@greenapps Ahh, I found all I need to do is put my code inside it. — Jian-Lun, Mar 30 '17 at 02:57

score 3 · Answer 1 · answered Mar 29 '17 at 13:11

For doing image processing based operations you can use with OpenCV Library. Here i given sample code to process the frames directly from camera using OpenCV

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.JavaCameraView;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.Mat;

import static org.opencv.core.CvType.CV_8UC1;

public class MainActivity extends AppCompatActivity implements CameraBridgeViewBase.CvCameraViewListener2 {

    private static final String TAG = "MainActivity";
    JavaCameraView javaCameraView;
    Mat frame;
    public static final int CAMERA_PERMISSION_REQUEST_CODE = 3;

    static {
        System.loadLibrary("MyOpenCVLibs");
    }

    private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
        @Override
        public void onManagerConnected(int status) {
            switch(status){
                case LoaderCallbackInterface.SUCCESS:
                {
                    javaCameraView.enableView();
                } break;
                default:
                {
                    super.onManagerConnected(status);
                } break;
            }
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (ContextCompat.checkSelfPermission(this,Manifest.permission.CAMERA)!= PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.CAMERA},CAMERA_PERMISSION_REQUEST_CODE);
        }

        javaCameraView = (JavaCameraView) findViewById(R.id.java_camera_view);
        javaCameraView.setVisibility(View.VISIBLE);
        javaCameraView.setCvCameraViewListener(this);
    }

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

    @Override
    protected void onDestroy(){
        super.onDestroy();
        if(javaCameraView!=null)
            javaCameraView.disableView();
    }

    @Override
    protected void  onResume(){

        super.onResume();
        if (OpenCVLoader.initDebug()) {
            Log.i(TAG, "OpenCV loaded successfully.");
            mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
        } else {
            Log.i(TAG, "OpenCV not loaded.");
            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_1_0, this, mLoaderCallback);
        }
    }

    @Override
    public void onCameraViewStarted(int width, int height) {
        frame=new Mat(height,width,CV_8UC4);

    }

    @Override
    public void onCameraViewStopped() {
        frame.release();
    }

    @Override
    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
        frame=inputFrame.rgba();

    }
}

This code checks OpenCV properly imported or not and Checks permission for Camera.
And each input frames are saved in frame variable.

Android - Real-Time get image data from camera?

1 Answers1