为什么 BoofCV 不断向左旋转 Camera Preview？

Question

我正在尝试将 BoofCV 线检测与来自 the BoofCV Android Demo 的给定示例一起使用。为此，我复制了 classes 并使用来自 Android 的相机 API 设置了所有内容。虽然演示使用的是横向，但我的 Activity 需要纵向，但设置时相机向左旋转 90°。当我尝试相应地设置相机时，没有任何反应。我用过：

Camera.setDisplayOrientation(90)
Camera.setParameters("orientation", "portrait")

一段时间后我发现它与设备无关（在不同的设备和 API 级别上测试过）并且它也与相机 API 没有任何关系（因为我在注释掉 VideoProcessor.init() 函数时设法得到它的肖像）。

尝试了一段时间后，我仍然不明白为什么 VideoProcessor 一直向左旋转图像...

这是我的 VideoProcessor 代码：

public class LineProcessor extends Thread implements VideoProcessing {

    /**
     * Lock for reading and writing images with processing and render
     */
    private final Object lockGui = new Object();

    /**
     * Lock used when converting the video stream.
     */
    private final Object lockConvert = new Object();

    private Paint mPaint;
    private ImageType<GrayU8> imageType;
    private GrayU8 image;
    private GrayU8 image2;
    private volatile boolean requestStop = false;
    private volatile boolean running = false;
    private int outputWidth;
    private int outputHeight;
    private View view;
    private Thread thread;

    private DetectLine detector;
    private FastQueue<LineSegment2D_F32> lines = new FastQueue<LineSegment2D_F32>(LineSegment2D_F32.class,true);
    private Bitmap bitmap;
    private byte[] storage;

    private double scale;
    private double tranX,tranY;

    /**
     * Creates a new Line Processor from a Line Detector
     * @param detector the Line Detector Segment
     */
    public LineProcessor(DetectLine detector) {
        this.imageType = ImageType.single(GrayU8.class);
        this.detector = detector;

        mPaint = new Paint();
        mPaint.setColor(Color.RED);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(2.0f);
    }

    @Override
    public void init(View view, Camera camera) {
        synchronized (lockGui) {
            this.view = view;

            Camera.Size size = camera.getParameters().getPreviewSize();
            outputWidth = size.width;
            outputHeight = size.height;
            declareImages(size.width,size.height);
        }

        // start the thread for processing
        running = true;
        start();
    }



    @Override
    public void onDraw(Canvas canvas) {
        synchronized (lockGui) {
            // the process class could have been swapped
            if( image == null )
                return;

            int w = view.getWidth();
            int h = view.getHeight();

            // fill the window and center it
            double scaleX = w/(double)outputWidth;
            double scaleY = h/(double)outputHeight;

            scale = Math.min(scaleX,scaleY);
            tranX = (w-scale*outputWidth)/2;
            tranY = (h-scale*outputHeight)/2;

            canvas.translate((float)tranX,(float)tranY);
            canvas.scale((float)scale,(float)scale);

            render(canvas, scale);
        }
    }



    @Override
    public void convertPreview(byte[] bytes, Camera camera) {
        if( thread == null )
            return;

        synchronized ( lockConvert ) {
            ConvertUtils.nv21ToGray(bytes, image.width, image.height, image);

        }
        // wake up the thread and tell it to do some processing
        thread.interrupt();
    }

    @Override
    public void stopProcessing() {
        if( thread == null )
            return;

        requestStop = true;
        while( running ) {
            // wake the thread up if needed
            thread.interrupt();
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {}
        }
    }

    @Override
    public void run() {
        thread = Thread.currentThread();
        while( !requestStop ) {
            synchronized ( thread ) {
                try {
                    wait();
                    if( requestStop )
                        break;
                } catch (InterruptedException e) {}
            }

            // swap gray buffers so that convertPreview is modifying the copy which is not in use
            synchronized ( lockConvert ) {
                GrayU8 tmp = image;
                image = image2;
                image2 = tmp;
            }

            process(image2);

            view.postInvalidate();
        }
        running = false;
    }

    /**
     * Scaling applied to the drawing canvas
     */
    public double getScale() {
        return scale;
    }

    /**
     * Translation x applied to the drawing canvas
     */
    public double getTranX() {
        return tranX;
    }

    /**
     * Translation y applied to the drawing canvas
     */
    public double getTranY() {
        return tranY;
    }


    public void process(GrayU8 gray) {

        if( detector != null ) {
            List<LineParametric2D_F32> found = detector.detect(gray);

            synchronized ( lockGui ) {
                ConvertUtils.grayToBitmap(gray,bitmap,storage);
                lines.reset();
                for( LineParametric2D_F32 p : found ) {
                    LineSegment2D_F32 ls = ConvertUtils.convert(p, gray.width,gray.height);
                    lines.grow().set(ls.a,ls.b);
                }
            }

        }
    }

    protected void render(Canvas canvas, double imageToOutput) {

        canvas.drawBitmap(bitmap,0,0,null);

        for( LineSegment2D_F32 s : lines.toList() )  {
            canvas.drawLine(s.a.x,s.a.y,s.b.x,s.b.y,mPaint);
        }

}

    protected void declareImages( int width , int height ) {
        image = imageType.createImage(width, height);
        image2 = imageType.createImage(width, height);

        bitmap = Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
        storage = ConvertUtils.declareStorage(bitmap,storage);
    }
}

我扩展的class是VideoProcessing.java

有人遇到过这个问题吗？

Answer 1

解决方案是将渲染函数更改为以下内容：

    protected void render(Canvas canvas, double imageToOutput) {

        canvas.rotate(90, 640f/2, 480f/2);
        canvas.scale(480f/640f, 640f/480f, 640f/2, 480f/2);
        canvas.drawBitmap(bitmap,0,0,null);

        for( LineSegment2D_F32 s : lines.toList() )  {
            canvas.drawLine(s.a.x,s.a.y,s.b.x,s.b.y,mPaint);
        }
}

我以前认为这不是干净的方式，但它实际上是唯一的工作方式....

为什么 BoofCV 不断向左旋转 Camera Preview？

Why does BoofCV constantly rotate the Camera Preview to the left?

android

android-camera

android-canvas

boofcv