OpenCV for Android——实时图像处理之表格切割

港控/mmm° 2021-08-30 18:46 344阅读 0赞

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNjA4MDAw_size_16_color_FFFFFF_t_70]

--------------------

QQ 1274510382  
Wechat JNZ\_aming  
商业互捧 QQ群538250800  
技术搞事 QQ群599020441  
技术合作 QQ群152889761  
加入我们 QQ群649347320  
纪年科技aming  
网络安全 ,深度学习,嵌入式,机器强化,生物智能,生命科学。

--------------------

灰化、  
Canny边缘检测、  
Hist直方图计算、  
Sobel边缘检测、  
SEPIA(色调变换)、  
ZOOM放大镜、  
PIXELIZE像素化  
https://blog.csdn.net/u012556077/article/details/79072340

--------------------

##### 》图像信息获取保存、处理和显示： #####

1.在OpenCV中一般都是使用Mat类型来存储图像等矩阵信息，  
所以我们可以声明一个Mat对象用来作为实时帧图像的缓存对象：

//缓存相机每帧输入的数据 
    private Mat mRgba;

对象实例化以及基本属性的设置，包括：长度、宽度和图像类型标志：

public void onCameraViewStarted(int width, int height) {   
        // TODO Auto-generated method stub 
        mRgba = new Mat(height, width, CvType.CV_8UC4);  
    }

对象赋值

/** * 图像处理都写在此处 */  
    @Override  
    public Mat onCameraFrame(CvCameraViewFrame inputFrame) {   
        switch (Cur_State) {   
        case 1:  
            //灰化处理 
            Imgproc.cvtColor(inputFrame.gray(), mRgba, Imgproc.COLOR_GRAY2RGBA,4);  
            break;  
        default:  
            //显示原图 
            mRgba = inputFrame.rgba();  
            break;  
        }  
        //返回处理后的结果数据 
        return mRgba;  
    }

由于用对象存储图像数据的话，  
数据会保存到内存中，所以结束的时候需要进行数据释放，  
不然可能导致崩溃：

@Override  
    public void onCameraViewStopped() {   
        // TODO Auto-generated method stub 
        mRgba.release();  
    }

private Mat mRgba,mTmp;  ;
    
    
    //对象实例化及基本属性的设置，包括长度、宽度和图像类型标志
        public void onCameraViewStarted(int width, int height) { 
            Log.e("Mat","...............4...............");
            mRgba = new Mat(height, width, CvType.CV_8UC4);
    
    
            ///
            mTmp = new Mat(height, width, CvType.CV_8UC4);
        }
    
    
    
     //Canny边缘检测 ///二值化
            mRgba = inputFrame.rgba();
            Imgproc.Canny(inputFrame.gray(), mTmp, 80, 100);
            Imgproc.cvtColor(mTmp, mRgba, Imgproc.COLOR_GRAY2RGBA, 4);

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNjA4MDAw_size_16_color_FFFFFF_t_70 1]

package com.e.opcv;
    import org.opencv.android.BaseLoaderCallback;
    import org.opencv.android.CameraActivity;
    import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
    import org.opencv.android.LoaderCallbackInterface;
    import org.opencv.android.OpenCVLoader;
    import org.opencv.android.Utils;
    import org.opencv.core.CvType;
    import org.opencv.core.Mat;
    import org.opencv.android.CameraBridgeViewBase;
    import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;
    import org.opencv.imgcodecs.Imgcodecs;
    import org.opencv.imgproc.Imgproc;
    
    import android.content.pm.ActivityInfo;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.os.Bundle;
    import android.os.Environment;
    import android.os.Handler;
    import android.os.Message;
    import android.util.Log;
    import android.view.MenuItem;
    import android.view.MotionEvent;
    import android.view.SurfaceView;
    import android.view.View;
    import android.view.WindowManager;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.Toast;
    
    import java.io.File;
    import java.util.Collections;
    import java.util.Date;
    import java.util.List;
    
    
    public class MainActivity extends  CameraActivity implements CvCameraViewListener2{ 
        private static final String TAG = "OCVSample::Activity";
        //opencv接口标志
    
    
        /** * CV相机 */
        private CameraBridgeViewBase mOpenCvCameraView;
        //缓存相机每帧输入的数据
    
    
    
        private Mat mRgba,mTmp;  ;
        private Button button;
    
        private boolean              mIsJavaCamera = true;
        private MenuItem             mItemSwitchCamera = null;
    
    
    /** * 加载OpenCV的回调 * 通过OpenCV管理Android服务，初始化OpenCV */
        private BaseLoaderCallback mLoaderCallback ;
    
    
    
        public MainActivity() { 
            Log.i(TAG, "Instantiated new " + this.getClass());
        }
    
    
        Handler handler = new Handler(){ 
            @Override
            public void handleMessage(Message msg){ 
                super.handleMessage(msg);
                if(msg.what == 1){ 
                    button.performClick();
                }
            }
        };
    
    
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) { 
            Log.i(TAG, "called onCreate");
            super.onCreate(savedInstanceState);
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    
            setContentView(R.layout.activity_main);
    
    
            // //初始化并设置预览部件 // 初始化CV相机
            mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_java_surface_view);
    
            mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
            // 设置相机监听
            mOpenCvCameraView.setCvCameraViewListener(this);
    
    
    
    
            //拍照按键
            button = (Button) findViewById(R.id.deal_btn);
    
            button.setOnClickListener(new View.OnClickListener() { 
                @Override
                public void onClick(View v) { 
                    if(mRgba != null) { 
                        if(!mRgba.empty()) { 
                            Mat inter = new Mat(mRgba.width(), mRgba.height(), CvType.CV_8UC4);
                            Log.e("Mat","...............1...............");
                            //将四通道的RGBA转为三通道的BGR，重要！！
                            Imgproc.cvtColor(mRgba, inter, Imgproc.COLOR_RGBA2BGR);
                            Log.e("Mat","...............2...............");
                            File sdDir = null;
                            //判断是否存在机身内存
                            boolean sdCardExist = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);
                            if(sdCardExist) { 
                                //获得机身储存根目录
                                sdDir = Environment.getExternalStorageDirectory();
                                Log.e("Mat","...............3...............");
                            }
                            //将拍摄准确时间作为文件名
                            java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat("yyyy-MM-dd_HH-mm-ss");
                            String filename = sdf.format(new Date());
                            String savepath=sdDir + "/Pictures/OpenCV/";
                            File f=new File(savepath);
                            if(!f.exists()){ 
                                f.mkdirs();
                            }
                            String filePath = sdDir + "/Pictures/OpenCV/" + filename + ".png";
                            Log.e("Mat","..............."+filePath+"...............");
                            //将转化后的BGR矩阵内容写入到文件中
                            Imgcodecs.imwrite(filePath, inter);
                            Toast.makeText(MainActivity.this, "图片保存到: "+ filePath, Toast.LENGTH_SHORT).show();
                        }
                    }
                }
            });
    
            // moveTaskToBack(true);
    // new test().start();
    
    
    
            // 连接到OpenCV的回调
            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;
                    }
                }
            };
    
    
    
    
        }
    
    
    
        private class test extends Thread{ 
            @Override
            public void run() { 
                super.run();
                while (true){ 
                    try { 
                        Thread.sleep(2000);
                        Log.e("begin","kaishi.........");
    
                        Message message = new Message();
                        message.what = 1;
                        handler.sendMessage(message);
                    }catch (Exception e){ 
                        Log.e("error",e.getMessage());
                    }
                }
            }
        }
    
    
    
    
    
    
        @Override
        public void onPause()
        { 
            super.onPause();
            if (mOpenCvCameraView != null)
                mOpenCvCameraView.disableView();
        }
    
        @Override
        public void onResume()
        { 
    
    
    
    
            // 界面加载完成的时候向OpenCV的连接回调发送连接成功的信号
            if (!OpenCVLoader.initDebug()) { 
                Log.d(TAG, "Internal OpenCV library not found. Using OpenCV Manager for initialization");
                OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_0_0, this, mLoaderCallback);
            } else { 
                Log.d(TAG, "OpenCV library found inside package. Using it!");
                mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
            }
    
            super.onResume();
        }
    
        @Override
        public List<? extends CameraBridgeViewBase> getCameraViewList() { 
            return Collections.singletonList(mOpenCvCameraView);
        }
    
        @Override
        public boolean onTouch(View v, MotionEvent event) { 
            return false;
        }
    
        public void onDestroy() { 
            super.onDestroy();
            if (mOpenCvCameraView != null)
                mOpenCvCameraView.disableView();
        }
    
    
        //对象实例化及基本属性的设置，包括长度、宽度和图像类型标志
        public void onCameraViewStarted(int width, int height) { 
            Log.e("Mat","...............4...............");
            mRgba = new Mat(height, width, CvType.CV_8UC4);
    
    
            ///
            mTmp = new Mat(height, width, CvType.CV_8UC4);
        }
    
    
    
    
        /**图像处理都写在这里！！！**/
        public Mat onCameraFrame(CvCameraViewFrame inputFrame) { 
    
    
           //灰度
            Imgproc.cvtColor(inputFrame.gray(), mRgba, Imgproc.COLOR_GRAY2RGBA,4);
    
            //Canny边缘检测 ///二值化
            mRgba = inputFrame.rgba();
            Imgproc.Canny(inputFrame.gray(), mTmp, 80, 100);
            Imgproc.cvtColor(mTmp, mRgba, Imgproc.COLOR_GRAY2RGBA, 4);
    
    
    // mRgba = inputFrame.rgba(); //一定要有！！！不然数据保存不进MAT中！！！
            //直接返回输入视频预览图的RGB数据并存放在Mat数据中
            Log.e("Mat","...............5...............");
            return mRgba;
    
        }
    
        @Override
        public void onPointerCaptureChanged(boolean hasCapture) { 
    
        }
    
    
        //结束时释放
        public void onCameraViewStopped() { 
    
            Log.e("Mat","...............6...............");
            mRgba.release();
            // mTmp.release();
        }
    
    
    
    
    
    
    
        }

https://pqpo.me/2017/09/11/opencv-border-recognition/

#### 》》形态学处理保留直线 霍夫直线检测 ####

*  霍夫直线检测的作用——计算得到输入图像  
    （一般是二值化的边缘检测结果图像）中包含的所有直线的数目与位置

在取得图像边缘的基础上，
    对一些特定的几何形状边缘，
    如直线、圆，通过图像霍夫变换把图像从平面坐标空间变换到霍夫坐标空间，
    就可以通过求取霍夫空间的局部极大值方法
    （其实就是霍夫空间中的曲线交集点）,
    得到极坐标空间对应参数方程中直线的两个参数（r，θ），
    从而计算得到边缘图像中的所有直线（基于平面坐标）的数目与位置。

参考文献：  
https://www.jianshu.com/p/ae5b49b4e5a2  
https://www.sohu.com/a/279670020\_823210  
https://www.cnblogs.com/cheermyang/p/5348820.html

https://vimsky.com/examples/detail/java-method-org.opencv.imgproc.Imgproc.HoughLinesP.html  
（…霍夫直线检测　Imgproc.HoughLinesP ）

http://www.what21.com/sys/view/media\_img\_1536741795822.html  
（　图形图像上的拉普拉斯平滑（Imgproc.line） ）

#### 数学形态学中运算 ####

有 膨胀（或扩张）、腐蚀（或侵蚀）、开启、闭合、骨架抽取、极线腐蚀、击中击不中变换、Top-hat变换、颗粒分析、流域变换、形态学梯度等，  
其中腐蚀与扩张就是我们今天所有讲的要点。  
opencv中对腐蚀和扩张有相对的函数去实现，多用于图像的取噪、分割出独立的图像元素，在图像中连接相邻的元素、寻找图像中明显的极大值或极小值区、求图像的梯度。  
————————————————

https://blog.csdn.net/xuyankuanrong/article/details/79145730  
( android使用opencv图片腐蚀与扩张 )  
https://blog.csdn.net/m1109048058/article/details/76640714  
（膨胀与腐蚀）

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNjA4MDAw_size_16_color_FFFFFF_t_70 2]

package com.e.opcv;
    import org.opencv.android.BaseLoaderCallback;
    import org.opencv.android.CameraActivity;
    import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
    import org.opencv.android.LoaderCallbackInterface;
    import org.opencv.android.OpenCVLoader;
    import org.opencv.android.Utils;
    import org.opencv.core.CvType;
    import org.opencv.core.Mat;
    import org.opencv.android.CameraBridgeViewBase;
    import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;
    import org.opencv.core.Size;
    import org.opencv.imgcodecs.Imgcodecs;
    import org.opencv.imgproc.Imgproc;
    
    import android.content.pm.ActivityInfo;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.Point;
    import android.os.Bundle;
    import android.os.Environment;
    import android.os.Handler;
    import android.os.Message;
    import android.util.Log;
    import android.view.MenuItem;
    import android.view.MotionEvent;
    import android.view.SurfaceView;
    import android.view.View;
    import android.view.WindowManager;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.Toast;
    
    import java.io.File;
    import java.util.Collections;
    import java.util.Date;
    import java.util.List;
    
    
    public class MainActivity extends  CameraActivity implements CvCameraViewListener2{ 
        private static final String TAG = "OCVSample::Activity";
        //opencv接口标志
    
    
        /** * CV相机 */
        private CameraBridgeViewBase mOpenCvCameraView;
        //缓存相机每帧输入的数据
    
    
    
        private Mat mRgba,mTmp;
        private Button button;
    
        private boolean              mIsJavaCamera = true;
        private MenuItem             mItemSwitchCamera = null;
    
    
    /** * 加载OpenCV的回调 * 通过OpenCV管理Android服务，初始化OpenCV */
        private BaseLoaderCallback mLoaderCallback ;
    
    
    
        public MainActivity() { 
            Log.i(TAG, "Instantiated new " + this.getClass());
        }
    
    
        Handler handler = new Handler(){ 
            @Override
            public void handleMessage(Message msg){ 
                super.handleMessage(msg);
                if(msg.what == 1){ 
                    button.performClick();
                }
            }
        };
    
    
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) { 
            Log.i(TAG, "called onCreate");
            super.onCreate(savedInstanceState);
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    
            setContentView(R.layout.activity_main);
    
    
            // //初始化并设置预览部件 // 初始化CV相机
            mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_java_surface_view);
    
            mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
            // 设置相机监听
            mOpenCvCameraView.setCvCameraViewListener(this);
    
    
    
    
            //拍照按键
            button = (Button) findViewById(R.id.deal_btn);
    
            button.setOnClickListener(new View.OnClickListener() { 
                @Override
                public void onClick(View v) { 
                    if(mRgba != null) { 
                        if(!mRgba.empty()) { 
                            Mat inter = new Mat(mRgba.width(), mRgba.height(), CvType.CV_8UC4);
                            Log.e("Mat","...............1...............");
                            //将四通道的RGBA转为三通道的BGR，重要！！
                            Imgproc.cvtColor(mRgba, inter, Imgproc.COLOR_RGBA2BGR);
                            Log.e("Mat","...............2...............");
                            File sdDir = null;
                            //判断是否存在机身内存
                            boolean sdCardExist = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);
                            if(sdCardExist) { 
                                //获得机身储存根目录
                                sdDir = Environment.getExternalStorageDirectory();
                                Log.e("Mat","...............3...............");
                            }
                            //将拍摄准确时间作为文件名
                            java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat("yyyy-MM-dd_HH-mm-ss");
                            String filename = sdf.format(new Date());
                            String savepath=sdDir + "/Pictures/OpenCV/";
                            File f=new File(savepath);
                            if(!f.exists()){ 
                                f.mkdirs();
                            }
                            String filePath = sdDir + "/Pictures/OpenCV/" + filename + ".png";
                            Log.e("Mat","..............."+filePath+"...............");
                            //将转化后的BGR矩阵内容写入到文件中
                            Imgcodecs.imwrite(filePath, inter);
                            Toast.makeText(MainActivity.this, "图片保存到: "+ filePath, Toast.LENGTH_SHORT).show();
                        }
                    }
                }
            });
    
            // moveTaskToBack(true);
    // new test().start();
    
    
    
            // 连接到OpenCV的回调
            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;
                    }
                }
            };
    
    
    
    
        }
    
    
    
        private class test extends Thread{ 
            @Override
            public void run() { 
                super.run();
                while (true){ 
                    try { 
                        Thread.sleep(2000);
                        Log.e("begin","kaishi.........");
    
                        Message message = new Message();
                        message.what = 1;
                        handler.sendMessage(message);
                    }catch (Exception e){ 
                        Log.e("error",e.getMessage());
                    }
                }
            }
        }
    
    
    
    
    
    
        @Override
        public void onPause()
        { 
            super.onPause();
            if (mOpenCvCameraView != null)
                mOpenCvCameraView.disableView();
        }
    
        @Override
        public void onResume()
        { 
    
    
    
    
            // 界面加载完成的时候向OpenCV的连接回调发送连接成功的信号
            if (!OpenCVLoader.initDebug()) { 
                Log.d(TAG, "Internal OpenCV library not found. Using OpenCV Manager for initialization");
                OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_0_0, this, mLoaderCallback);
            } else { 
                Log.d(TAG, "OpenCV library found inside package. Using it!");
                mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
            }
    
            super.onResume();
        }
    
        @Override
        public List<? extends CameraBridgeViewBase> getCameraViewList() { 
            return Collections.singletonList(mOpenCvCameraView);
        }
    
        @Override
        public boolean onTouch(View v, MotionEvent event) { 
            return false;
        }
    
        public void onDestroy() { 
            super.onDestroy();
            if (mOpenCvCameraView != null)
                mOpenCvCameraView.disableView();
        }
    
    
        //对象实例化及基本属性的设置，包括长度、宽度和图像类型标志
        public void onCameraViewStarted(int width, int height) { 
            Log.e("Mat","...............4...............");
            mRgba = new Mat(height, width, CvType.CV_8UC4);
    
    
            ///
            mTmp = new Mat(height, width, CvType.CV_8UC4);
        }
    
    
    
    
        /**图像处理都写在这里！！！**/
        public Mat onCameraFrame(CvCameraViewFrame inputFrame) { 
    
    
           //灰度
            Imgproc.cvtColor(inputFrame.gray(), mRgba, Imgproc.COLOR_GRAY2RGBA,4);
    
            //Canny边缘检测 ///二值化
            mRgba = inputFrame.rgba();
            Imgproc.Canny(inputFrame.gray(), mTmp, 80, 100);
            Imgproc.cvtColor(mTmp, mRgba, Imgproc.COLOR_GRAY2RGBA, 4);
    
    
    
            Mat dilateImage = mRgba.clone();
            Mat erodeImage = mRgba.clone();
            Mat element = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size(3,3));
    
            //膨胀
            Imgproc.dilate(mRgba, dilateImage, element, new Point(-1, -1), 1);
            //腐蚀
            Imgproc.erode(mRgba, erodeImage, element, new Point(-1, -1), 1);
            
    
    
    
    // mRgba = inputFrame.rgba(); //一定要有！！！不然数据保存不进MAT中！！！
            //直接返回输入视频预览图的RGB数据并存放在Mat数据中
            Log.e("Mat","...............5...............");
            return mRgba;
    
        }
    
        @Override
        public void onPointerCaptureChanged(boolean hasCapture) { 
    
        }
    
    
        //结束时释放
        public void onCameraViewStopped() { 
    
            Log.e("Mat","...............6...............");
            mRgba.release();
            // mTmp.release();
        }
    
    
    
    
    
    
    
        }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNjA4MDAw_size_16_color_FFFFFF_t_70]: /images/20210725/839c92584303404cb08cbf53b0cffc4c.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNjA4MDAw_size_16_color_FFFFFF_t_70 1]: /images/20210725/acd0ac4b7af14e86a00cbfe7521e112f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNjA4MDAw_size_16_color_FFFFFF_t_70 2]: /images/20210725/801e5f577a8e4e8b9edc3d8a2e1c1372.png