OpenCV 相机方向问题

Question

我有一个简单的项目，它只显示带有 org.opencv.android.JavaCameraView 的相机。

我的问题是，默认情况下，相机处于横向模式，我无法更改这一点，因为我需要定义 CameraBridgeViewBase 而不是常规相机意图。

这是我的代码的一部分：

XML 代码：

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

            <org.opencv.android.JavaCameraView
                android:layout_width="fill_parent"
                android:layout_height="300dp"
                android:visibility="gone"
                android:id="@+id/HelloOpenCvView"
                opencv:show_fps="true"
                opencv:camera_id="1" />


        </LinearLayout>  

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >


            <Button
                android:id="@+id/BtnVideo"
                android:layout_marginLeft="2dp"
                android:layout_marginRight="2dp"                    
                android:layout_width="0dp"
                style="@style/button"
                android:layout_height="wrap_content"
                android:layout_weight="1.00"
                android:text="@string/videoBtn"
                android:textSize="18dip" />


        </LinearLayout>   

代码：

 CameraBridgeViewBase mOpenCvCameraView;
    Button VideoButton;
 protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        overridePendingTransition(0, 0);

        VideoButton = (Button) this.findViewById(R.id.BtnVideo);

        VideoButton.setOnClickListener(onClickListener);

        mOpenCvCameraView= (CameraBridgeViewBase) findViewById(R.id.HelloOpenCvView);
        mOpenCvCameraView.setVisibility(SurfaceView.INVISIBLE);

    } 

        private OnClickListener onClickListener = new OnClickListener() {

            @Override
            public void onClick(View v) {
                    switch (v.getId()){

                        case R.id.BtnVideo:
                            if(mOpenCvCameraView.getVisibility() == SurfaceView.VISIBLE)
                            {
                                mOpenCvCameraView.setVisibility(SurfaceView.INVISIBLE);
                            }
                            else
                            {
                                mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
                            }

                            break;
                        default :
                            break;
                    }

            }
        };


        public void onResume() {
            super.onResume();
            overridePendingTransition(0, 0);
            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
        }
         public void onPause()
         {
             super.onPause();
             if (mOpenCvCameraView != null)
                 mOpenCvCameraView.disableView();
         }
         public void onDestroy() {
             super.onDestroy();
             if (mOpenCvCameraView != null)
                 mOpenCvCameraView.disableView();
         }
         public void onCameraViewStarted(int width, int height) {
         }

         public void onCameraViewStopped() {
         }
         public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
             return inputFrame.rgba();
         }

        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;
                }
            }
        };

那么如何更改默认方向？

谢谢！

Answer 1

好的，我发现这是一个解决方案：

首先我进入OpenCV 库中的JavaCameraView.java类- 2.4.5

然后在mCamera.startPreview();之前的initializeCamera()函数中mCamera.startPreview(); 我添加了这两个功能：

            setDisplayOrientation(mCamera, 90);
            mCamera.setPreviewDisplay(getHolder());

第一个函数是这样实现的：

protected void setDisplayOrientation(Camera camera, int angle){
    Method downPolymorphic;
    try
    {
        downPolymorphic = camera.getClass().getMethod("setDisplayOrientation", new Class[] { int.class });
        if (downPolymorphic != null)
            downPolymorphic.invoke(camera, new Object[] { angle });
    }
    catch (Exception e1)
    {
        e1.printStackTrace();
    }
}

我只是提醒我使用 OpenCV。

希望这有助于某人。

Answer 2

我正在使用 OpenCV 3.1，我通过在 CameraBridgeViewBase 类的 deliveryAndDrawFrame 方法上绘制位图时应用变换来修复它，希望它有帮助：

在 CameraBridgeViewBase.java 上：

//I added new field
private final Matrix mMatrix = new Matrix();

//added updateMatrix method 
private void updateMatrix() {
    float hw = this.getWidth() / 2.0f;
    float hh = this.getHeight() / 2.0f;
    boolean isFrontCamera = Camera.CameraInfo.CAMERA_FACING_FRONT == mCameraIndex;
    mMatrix.reset();
    if (isFrontCamera) {
        mMatrix.preScale(-1, 1, hw, hh);
    }
    mMatrix.preTranslate(hw, hh);
    if (isFrontCamera)
        mMatrix.preRotate(270);
    else
        mMatrix.preRotate(90);
    mMatrix.preTranslate(-hw, -hh);
}

//then We need call updateMatrix on layout
@Override
public void layout(int l, int t, int r, int b) {
    super.layout(l, t, r, b);
    updateMatrix();
}

//I think we should also call updateMatrix on measure
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    updateMatrix();
}


//then We need update deliverAndDrawFrame
protected void deliverAndDrawFrame(CvCameraViewFrame frame) {
    //....Origin Code...

    //Set matrix before OpenCV draw bitmap
    int saveCount = canvas.save();
    canvas.setMatrix(mMatrix);

    //Begin OpenCv origin source
    if (mScale != 0) {
        canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
             new Rect((int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2),
             (int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2),
             (int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2 + mScale*mCacheBitmap.getWidth()),
             (int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2 + mScale*mCacheBitmap.getHeight())), null);
    } else {
         canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
             new Rect((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,
             (canvas.getHeight() - mCacheBitmap.getHeight()) / 2,
             (canvas.getWidth() - mCacheBitmap.getWidth()) / 2 + mCacheBitmap.getWidth(),
             (canvas.getHeight() - mCacheBitmap.getHeight()) / 2 + mCacheBitmap.getHeight()), null);
    }
    //End OpenCv origin source

    //Restore canvas after draw bitmap
    canvas.restoreToCount(saveCount);

    //....Origin code...
}



//After that We can see that the camera preview is so small, the easiest way is change mScale Value (should we change mScale to "private" instead "protected" ?)
protected void deliverAndDrawFrame(CvCameraViewFrame frame) {
    //....Origin Code...

    //Set matrix before OpenCV draw bitmap to screen
    int saveCount = canvas.save();
    canvas.setMatrix(mMatrix);


    //Change mScale to "Aspect to fill"
    mScale = Math.max((float) canvas.getHeight() / mCacheBitmap.getWidth(), (float) canvas.getWidth() / mCacheBitmap.getHeight());

    //Begin OpenCv origin source
    if (mScale != 0) {
        canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
             new Rect((int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2),
             (int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2),
             (int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2 + mScale*mCacheBitmap.getWidth()),
             (int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2 + mScale*mCacheBitmap.getHeight())), null);
    } else {
         canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
             new Rect((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,
             (canvas.getHeight() - mCacheBitmap.getHeight()) / 2,
             (canvas.getWidth() - mCacheBitmap.getWidth()) / 2 + mCacheBitmap.getWidth(),
             (canvas.getHeight() - mCacheBitmap.getHeight()) / 2 + mCacheBitmap.getHeight()), null);
    }
    //End OpenCv origin source

    //Restore canvas after draw bitmap
    canvas.restoreToCount(saveCount);

    //....Origin Code...
}

你可以在这里获得完整的源代码： https : //gist.github.com/thongdoan/d73267eb58863f70c77d1288fe5cd3a4

Answer 3

问题是绘制的代码不检查相机参数。 在“CameraBridgeViewBase”类的“deliverAndDrawFrame”函数中，在Surface视图上绘制Mat。

通过在 CameraBridgeViewBase 类中进行非常简单的修改，我们可以制作一个旋转位图绘制方式的函数。

int userRotation= 0;

public void setUserRotation(int userRotation) {
    this.userRotation = userRotation;
}

/**
 * This method shall be called by the subclasses when they have valid
 * object and want it to be delivered to external client (via callback) and
 * then displayed on the screen.
 * @param frame - the current frame to be delivered
 */
protected void deliverAndDrawFrame(CvCameraViewFrame frame) {
    Mat modified;

    if (mListener != null) {
        modified = mListener.onCameraFrame(frame);
    } else {
        modified = frame.rgba();
    }

    boolean bmpValid = true;
    if (modified != null) {
        try {
            Utils.matToBitmap(modified, mCacheBitmap);
        } catch(Exception e) {
            Log.e(TAG, "Mat type: " + modified);
            Log.e(TAG, "Bitmap type: " + mCacheBitmap.getWidth() + "*" + mCacheBitmap.getHeight());
            Log.e(TAG, "Utils.matToBitmap() throws an exception: " + e.getMessage());
            bmpValid = false;
        }
    }

    if (bmpValid && mCacheBitmap != null) {
        Canvas canvas = getHolder().lockCanvas();
        if (canvas != null) {
            canvas.drawColor(Color.parseColor("#8BC34A"), PorterDuff.Mode.SRC_IN);
 //this is the rotation part
            canvas.save();
            canvas.rotate(userRotation,  (canvas.getWidth()/ 2),(canvas.getHeight()/ 2));

            if (mScale != 0) {
                canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
                     new Rect((int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2),
                     (int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2),
                     (int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2 + mScale*mCacheBitmap.getWidth()),
                     (int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2 + mScale*mCacheBitmap.getHeight())), null);
            } else {
                 canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
                     new Rect((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,
                     (canvas.getHeight() - mCacheBitmap.getHeight()) / 2,
                     (canvas.getWidth() - mCacheBitmap.getWidth()) / 2 + mCacheBitmap.getWidth(),
                     (canvas.getHeight() - mCacheBitmap.getHeight()) / 2 + mCacheBitmap.getHeight()), null);
            }

            if (mFpsMeter != null) {
                mFpsMeter.measure();
                mFpsMeter.draw(canvas, 20, 30);
            }
//remember to restore the canvas 
            canvas.restore();
            getHolder().unlockCanvasAndPost(canvas);
        }
    }
}

我尝试了最常见的使用Core.flip函数旋转Mat但消耗大量资源的解决方案，该解决方案不影响检测，不影响性能，只是改变了图像的绘制方式在画布上。

希望这有帮助。

Answer 4

在您的 onCameraFrame 上试试这个

 mRgba = inputFrame.rgba();
 Mat mRgbaT = mRgba.t();
 Core.flip(mRgba.t(), mRgbaT, 1);
 Imgproc.resize(mRgbaT, mRgbaT, mRgba.size());
 return mRgbaT;

Answer 5

首先，不要从基类创建实例，而是从扩展类获取实例

//CameraBridgeViewBase mOpenCvCameraView;
JavaCameraView mOpenCvCameraView;

值得一提的是，CameraBridgeViewBase.java 已经有一个surface holder，所以让我们使用它而不是创建一个表面纹理。

因此，其次，通过用表面支架替换表面纹理来编辑函数 initializeCamera() 内的 JavaCameraView.java

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {

    //mSurfaceTexture = new SurfaceTexture(MAGIC_TEXTURE_ID);
    //mCamera.setPreviewTexture(mSurfaceTexture);

    mCamera.setPreviewDisplay(getHolder());

} else
    mCamera.setPreviewDisplay(null);

最后一步是在不添加任何特殊功能的情况下设置方向。 在同一个函数 initializeCamera() 之前 startPreview() 调用 setDisplayOrientation(degrees)

/* Finally we are ready to start the preview */
Log.d(TAG, "startPreview");
mCamera.setDisplayOrientation(90);
mCamera.startPreview();

Answer 6

在 OpenCV 版本 3.4.3 中

我通过在 JavaCameraView.java 类中的 initializeCamera() 方法中进行以下更改来修复它。

setDisplayOrientation(mCamera, 0);

要遵循的步骤：

1. 转到 JavaCameraView.java 文件。
2. 搜索“setDisplayOrientation”
3. 将方向角设置为 0（默认为 90）。

Answer 7

AndroidManifest.xml 中的 android:screenOrientation 值应该会有所帮助。

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