從SurfaceView的相機流中獲取RGB

Question

我無法從surfaceView獲取RGB值。我正在與Xamarin，C＃合作。 試圖用getBitmap，但這種方法不適合SurfaceView .. 我需要通過觸摸surfaceView一些地方，從相機的實時數據流RGB。 也許我需要使用別的東西而不是surfaceView？ '

public class MainActivity : Activity, ISurfaceHolderCallback, Camera.IPreviewCallback, View.IOnTouchListener 
    { 
Camera _camera; 
     SurfaceView _surfaceview; 
     int redValue,blueValue,greenValue; 
     int pixel; 
     Bitmap bitmap; 
     TextView _textview; 


     protected override void OnCreate (Bundle savedInstanceState) 
     { 
      base.OnCreate (savedInstanceState); 
      SetContentView (Resource.Layout.Main); 
      _surfaceview = (SurfaceView)FindViewById (Resource.Id.surfaceView1); 
      _surfaceview.SetOnTouchListener (this); 
      var holder = _surfaceview.Holder; 
      holder.AddCallback (this); 
      holder.SetType (Android.Views.SurfaceType.PushBuffers); 


      TabHost tabhost = FindViewById<TabHost> (Resource.Id.myTab); 

      tabhost.Setup(); 

      TabHost.TabSpec tabhost1 = tabhost.NewTabSpec ("Tab1"); 
      tabhost1.SetContent (Resource.Id.tab1); 
      tabhost1.SetIndicator ("CAMERA"); 
      tabhost.AddTab (tabhost1); 

      TabHost.TabSpec tabhost2 = tabhost.NewTabSpec ("Tab2"); 
      tabhost2.SetContent (Resource.Id.tab2); 
      tabhost2.SetIndicator ("RGB"); 
      tabhost.AddTab (tabhost2); 

      _textview = (TextView)FindViewById (Resource.Id.textView1); 

     } 

     public bool OnTouch(View v, MotionEvent e) 
     { 
      switch (e.Action) 
      { 
      case MotionEventActions.Down: 
       break; 
      case MotionEventActions.Up: 
       pixel = bitmap.GetPixel ((int)e.GetX(), (int)e.GetY()); 
       var _color = new Color (pixel); 
       redValue = _color.R; 
       blueValue = _color.G; 
       greenValue = _color.B; 
       _textview.Text = "Hello"; 
       break; 
      } 
      return true; 
     } 

     public void SurfaceCreated(ISurfaceHolder holder) 
     { 
      try{ 
       _camera = Android.Hardware.Camera.Open(); 
       Android.Hardware.Camera.Parameters p = _camera.GetParameters(); 
       p.PictureFormat = Android.Graphics.ImageFormatType.Jpeg; 
       _camera.SetParameters(p); 
       _camera.SetPreviewCallback(this); 
       _camera.Lock(); 

       _camera.SetDisplayOrientation(90); 
       _camera.SetPreviewDisplay(holder); 
       _camera.StartPreview(); 

      } 
      catch(System.IO.IOException e){ 
      } 
     } 

     public void SurfaceDestroyed(ISurfaceHolder holder){ 

      _camera.Unlock(); 
      _camera.StopPreview(); 
      _camera.Release(); 
     } 

     public void SurfaceChanged(ISurfaceHolder holder,Android.Graphics.Format f,int i, int j) 
     { 
     } 

     void Camera.IPreviewCallback.OnPreviewFrame(byte[] b, Android.Hardware.Camera c) 
     { 
     } 

    }} 

`

Answer 1

在PreviewCallBack

：

Camera.Parameters parameters = camera.getParameters(); 
      Camera.Size size = parameters.getPreviewSize(); 
      Camera.CameraInfo info = new Camera.CameraInfo(); 
      Camera.getCameraInfo(0, info); 
      if(mBitmapWidth == 0 || mBitmapHeight == 0) { 
       mBitmapWidth = size.width; 
       mBitmapHeight = size.height; 
      } 

      mCurrentImageRGB = new int[mBitmapWidth*mBitmapHeight]; 
      Recognize.decodeYUV420SP2(mCurrentImageRGB, data, mBitmapWidth, mBitmapHeight); 

在CameraPreview：

mCamera.getParameters().setPreviewFormat(ImageFormat.NV21); 

在surfaceChanged

：

setCameraDisplayOrientation((Activity)mContext,0,mCamera); 

和setCameraDisplayOrientation（此方法我在CameraPreview類加）：

public static void setCameraDisplayOrientation(Activity activity, int cameraId, android.hardware.Camera camera) { 
     android.hardware.Camera.CameraInfo info = new android.hardware.Camera.CameraInfo(); 
     android.hardware.Camera.getCameraInfo(cameraId, info); 
     int rotation = activity.getWindowManager().getDefaultDisplay().getRotation(); 
     int degrees = 0; 
     switch (rotation) { 
      case Surface.ROTATION_0: 
       degrees = 0; 
       break; 
      case Surface.ROTATION_90: 
       degrees = 90; 
       break; 
      case Surface.ROTATION_180: 
       degrees = 180; 
       break; 
      case Surface.ROTATION_270: 
       degrees = 270; 
       break; 
     } 

     int result; 
     if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) { 
      result = (info.orientation + degrees) % 360; 
      result = (360 - result) % 360; 
     } else { 
      result = (info.orientation - degrees + 360) % 360; 
     } 

     camera.setDisplayOrientation(result); 
    } 

希望這將有助於）

在mCurrentImageRGB

將是你的int數組與RGB整數這個形象，你可以將它們做它任何你想要的）

int middlePixel = mCurrentImageRGB[mBitmapWidth/2 + mBitmapHeight/2]; // this is your rgb pixel somewhere in center of image :) 

我忘了，解碼器：

public static void decodeYUV420SP2(int[] rgb, byte[] yuv420sp, int width, int height) { 

     final int frameSize = width * height; 

     for (int j = 0, yp = 0; j < height; j++) { 
      int uvp = frameSize + (j >> 1) * width, u = 0, v = 0; 
      for (int i = 0; i < width; i++, yp++) { 
       int y = (0xff & ((int) yuv420sp[yp])) - 16; 
       if (y < 0) 
        y = 0; 
       if ((i & 1) == 0) { 
        v = (0xff & yuv420sp[uvp++]) - 128; 
        u = (0xff & yuv420sp[uvp++]) - 128; 
       } 

       int y1192 = 1192 * y; 
       int r = (y1192 + 1634 * v); 
       int g = (y1192 - 833 * v - 400 * u); 
       int b = (y1192 + 2066 * u); 

       if (r < 0) 
        r = 0; 
       else if (r > 262143) 
        r = 262143; 
       if (g < 0) 
        g = 0; 
       else if (g > 262143) 
        g = 262143; 
       if (b < 0) 
        b = 0; 
       else if (b > 262143) 
        b = 262143; 
       rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff); 
      } 
     } 
    }