OpenCV 相機方向問題

Question

我有一個簡單的項目，它只顯示帶有 org.opencv.android.JavaCameraView 的相機。

我的問題是，默認情況下，相機處於橫向模式，我無法更改這一點，因為我需要定義 CameraBridgeViewBase 而不是常規相機意圖。

這是我的代碼的一部分：

XML 代碼：

        <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>   

代碼：

 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;
                }
            }
        };

那么如何更改默認方向？

謝謝！

Answer 1

好的，我發現這是一個解決方案：

首先我進入OpenCV 庫中的JavaCameraView.java類- 2.4.5

然后在mCamera.startPreview();之前的initializeCamera()函數中mCamera.startPreview(); 我添加了這兩個功能：

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

第一個函數是這樣實現的：

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。

希望這有助於某人。

Answer 2

我正在使用 OpenCV 3.1，我通過在 CameraBridgeViewBase 類的 deliveryAndDrawFrame 方法上繪制位圖時應用變換來修復它，希望它有幫助：

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...
}

你可以在這里獲得完整的源代碼： https : //gist.github.com/thongdoan/d73267eb58863f70c77d1288fe5cd3a4

Answer 3

問題是繪制的代碼不檢查相機參數。 在“CameraBridgeViewBase”類的“deliverAndDrawFrame”函數中，在Surface視圖上繪制Mat。

通過在 CameraBridgeViewBase 類中進行非常簡單的修改，我們可以制作一個旋轉位圖繪制方式的函數。

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);
        }
    }
}

我嘗試了最常見的使用Core.flip函數旋轉Mat但消耗大量資源的解決方案，該解決方案不影響檢測，不影響性能，只是改變了圖像的繪制方式在畫布上。

希望這有幫助。

Answer 4

在您的 onCameraFrame 上試試這個

 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，不要從基類創建實例，而是從擴展類獲取實例

//CameraBridgeViewBase mOpenCvCameraView;
JavaCameraView mOpenCvCameraView;

值得一提的是，CameraBridgeViewBase.java 已經有一個surface holder，所以讓我們使用它而不是創建一個表面紋理。

因此，其次，通過用表面支架替換表面紋理來編輯函數 initializeCamera() 內的 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況下設置方向。 在同一個函數 initializeCamera() 之前 startPreview() 調用 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

我通過在 JavaCameraView.java 類中的 initializeCamera() 方法中進行以下更改來修復它。

setDisplayOrientation(mCamera, 0);

要遵循的步驟：

1. 轉到 JavaCameraView.java 文件。
2. 搜索“setDisplayOrientation”
3. 將方向角設置為 0（默認為 90）。

Answer 7

AndroidManifest.xml 中的 android:screenOrientation 值應該會有所幫助。

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