Question

我编写此代码以使用opencv4android实时检测功能。但是这个代码不能正常工作，我无法在此代码中找到错误，但我想错误的代码就是这个{detector.detect（mRgba，关键点）对不起我的糟糕解释，我很抱歉。我对这个主题真的很陌生。请帮帮我。

public class MainActivity extends Activity implements CvCameraViewListener2{
        private CameraBridgeViewBase    mOpenCvCameraView;
        private static final String     TAG = "feature detection";
        private Mat             mRgba, mGray;
        private FeatureDetector         detector;
        private DescriptorExtractor     SurfExtractor;
        private MatOfKeyPoint       keypoints;

            BaseLoaderCallback blc = new BaseLoaderCallback(this) {
            public void onManagerConnected(int status) {
                if(status == LoaderCallbackInterface.SUCCESS){
                Log.i(TAG, "OpenCV loaded successfully");
                mOpenCvCameraView.enableView();
                mOpenCvCameraView.setCameraIndex(0);
            }else{
                super.onManagerConnected(status);
            }
            };
        };

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
            this.requestWindowFeature(Window.FEATURE_NO_TITLE);
            setContentView(R.layout.activity_main);
            mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.cam);
            mOpenCvCameraView.setCvCameraViewListener(this);
        }

        @Override
        protected void onResume() {
            super.onResume();
            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_8, this,blc);
        }

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

        @Override
        public void onDestroy() {
            super.onDestroy();
            mOpenCvCameraView.disableView();
        }

        @Override
        public void onCameraViewStarted(int width, int height) {
            mRgba = new Mat(width, height, CvType.CV_8SC4);
            detector = FeatureDetector.create(FeatureDetector.ORB);
            SurfExtractor = DescriptorExtractor.create(DescriptorExtractor.ORB);
        }

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

        @Override
        public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
            mRgba = inputFrame.rgba();
                detector.detect(mRgba, keypoints);
            Features2d.drawKeypoints(mRgba, keypoints, mRgba);
            return mRgba;
        }
    }

Answer 1

使用opencv java包装器，您可以为结果/输出值传递空Mat，但不能为空值传递。

所以你必须至少调用m = new Mat（），或者在这种情况下，keypoints = new MatOfKeyPoint（）：

    @Override
    public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
        mRgba = inputFrame.rgba();
        keypoints = new MatOfKeyPoint();
            detector.detect(mRgba, keypoints);
        Features2d.drawKeypoints(mRgba, keypoints, mRgba);
        return mRgba;
    }

（与下一步中的描述符相同，顺便说一句。）

Answer 2

它必须改变inputFrame.rgba（）; to inputFrame.gray（）;以及

我使用openCV4Android的功能检测代码不起作用？

2 个答案: