如何从Android相机中找到框架的轮廓并将其转换为box2d实体？

使用openframeworks,OpenCV和Box2D,我能够以良好的帧速率实现它.使用 Android似乎是一项更复杂的任务(部分原因是我是JAVA新手).

这就是我的开始：

>使用“OpenCV示例 – 图像处理”并删除除“canny”效果之外的所有内容,这会产生一个漂亮的黑色&白色图像,非常适合找到轮廓.

public Mat onCameraFrame(CvCameraviewFrame inputFrame)
{
    mRgba = inputFrame.rgba();
    Imgproc.Canny(mRgbaInnerWindow,mIntermediateMat,50,100);
    Imgproc.cvtColor(mIntermediateMat,mRgbaInnerWindow,Imgproc.COLOR_GRAY2BGRA,4);

    return mRgba;
}

>从“OpenCV Sample – color-blob-detection”中我抓住了在Mat中找到轮廓的逻辑：

// These two lines are actually in the function onCameraviewStarted
mHierarchy = new Mat();
CONTOUR_COLOR = new Scalar(255,255);

// These lines are in function onCameraFrame
List<MatOfPoint> contours = new ArrayList<MatOfPoint>();        
Imgproc.findContours(mRgbaInnerWindow,contours,mHierarchy,Imgproc.RETR_EXTERNAL,Imgproc.CHAIN_APPROX_SIMPLE);
Imgproc.drawContours(mIntermediateMat,-1,CONTOUR_COLOR);

所以,我当前的函数看起来像这样,它不起作用：

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

    if ((mRgbaInnerWindow == null) || (mGrayInnerWindow == null) || (mRgba.cols() != mSizeRgba.width) || (mRgba.height() != mSizeRgba.height))
        CreateAuxiliaryMats();

    Imgproc.Canny(mRgbaInnerWindow,100);
    //Imgproc.cvtColor(mIntermediateMat,4);

    List<MatOfPoint> contours = new ArrayList<MatOfPoint>();

    Imgproc.findContours(mRgbaInnerWindow,Imgproc.CHAIN_APPROX_SIMPLE);
    //Imgproc.drawContours(mIntermediateMat,CONTOUR_COLOR);

    return mRgba;
}

>现在,这就是我被困的地方.我不断得到例外,我认为我没有使用正确的尺寸或将Mat转换为正确的颜色空间.这篇文章有一些见解,但我不知道它是否正确：OpenCV on Android findContours throws Exception

解决方法

嗨我也是openCV的新手,不过这段代码可能有帮助,

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceView;
import org.opencv.android.*;
import org.opencv.core.*;
import org.opencv.imgproc.Imgproc;


import java.util.ArrayList;
import java.util.List;

public class MainActivity extends Activity implements CvCameraviewListener2{

private static final String TAG = MainActivity.class.getCanonicalName();

private CameraBridgeViewBase mOpenCvCameraview;

private Mat                    mRgba;
private Mat                    mIntermediateMat;
private Mat                    mGray;
Mat hierarchy;


List<MatOfPoint> contours;

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;
        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mOpenCvCameraview = (CameraBridgeViewBase) findViewById(R.id.java_surface_view);
    mOpenCvCameraview.setVisibility(SurfaceView.VISIBLE);

    mOpenCvCameraview.setCvCameraviewListener(this);

}

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

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



@Override
public void onCameraviewStarted(int width,int height) {
    mRgba = new Mat(height,width,CvType.CV_8UC4);
    mIntermediateMat = new Mat(height,CvType.CV_8UC4);
    mGray = new Mat(height,CvType.CV_8UC1);
    hierarchy = new Mat();
}

@Override
public void onCameraviewStopped() {
    mRgba.release();
    mGray.release();
    mIntermediateMat.release();
    hierarchy.release();
}

@Override
public Mat onCameraFrame(CvCameraviewFrame inputFrame) {
     mRgba = inputFrame.gray();
        contours = new ArrayList<MatOfPoint>();
        hierarchy = new Mat();

     Imgproc.Canny(mRgba,80,100);
     Imgproc.findContours(mIntermediateMat,hierarchy,Imgproc.RETR_TREE,Imgproc.CHAIN_APPROX_SIMPLE,new Point(0,0));
    /* Mat drawing = Mat.zeros( mIntermediateMat.size(),CvType.CV_8UC3 );
     for( int i = 0; i< contours.size(); i++ )
     {
    Scalar color =new Scalar(Math.random()*255,Math.random()*255,Math.random()*255);
     Imgproc.drawContours( drawing,i,color,2,8,new Point() );
     }*/
     hierarchy.release();
     Imgproc.drawContours(mRgba,new Scalar(Math.random()*255,Math.random()*255));//,new Point());
    // Imgproc.cvtColor(mIntermediateMat,mRgba,Imgproc.COLOR_GRAY2RGBA,4);
    return mRgba;
}

}

我知道这可能不是实现这一目标的最佳方式,但我们都在这里学习新方法:)