カメラのプレビューのビットマップからピクセルを読み取る

Question

カメラのプレビューのビットマップを作成する必要があるAndroidアプリケーションを作成していますが、プレビューの中央にあるピクセルを平均することができますカメラが指し示されると、画面中央の9x9の正方形の平均値から読み取られたRGB値として、常に0、0、0が返されます。 preview.javaとメインのJavaファイルの両方があります。これはアンドロイドの問題ですか（もしそうであれば、その方法がありますか）、それとも私のコードに問題がありますか？ありがとう！あなたはピクセルがで返さ作成しないで、あなたの新しいビットマップb内の画素値は

import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import android.app.Activity; 
import android.graphics.Bitmap; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.hardware.Camera; 
import android.hardware.Camera.PictureCallback; 
import android.hardware.Camera.ShutterCallback; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.Display; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.Button; 
import android.widget.TextView; 
import android.widget.FrameLayout; 

public class CameraTest2Activity extends Activity { 
private static final String TAG = "ZTG"; 
Camera camera; 
Preview preview; 


/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    preview = new Preview(this); 
    ((FrameLayout) findViewById(R.id.preview)).addView(preview); 
    final Button button = (Button) findViewById(R.id.bFire); 
    button.setOnClickListener(new View.OnClickListener() { 
     public void onClick(View v) { 
      long timeAtStart = System.currentTimeMillis(); 
      TextView rgbDisplay = (TextView) findViewById(R.id.RGBText); 
      Display display = getWindowManager().getDefaultDisplay(); 
      int width = display.getWidth(); 
      int height = display.getHeight(); 
      Log.d(TAG, "Width and Height Retrieved As: " + width + ", " + height); 
      Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config. RGB_565); 
      Canvas c = new Canvas(b); 
      Preview view = (Preview) ((ViewGroup) findViewById(R.id.preview)).getChildAt(0); 
      view.draw(c); 
      String hexValue; 
      int centerX = (display.getWidth()/2); 
      int centerY = (display.getHeight()/2); 

      int test; 


      //test = b.getPixel(240, 350); 
      int sampleWidth = 9; 
      int sampleHeight = 9; 
      int[] pixels = new int[sampleWidth * sampleHeight]; 
      b.getPixels(pixels, 0, 9, centerX - 4, centerY - 4, sampleWidth, sampleHeight); 
      int l = 0; 
      int tempNum; 
      int tempBlue; 
      int tempRed; 
      int tempGreen; 
      int blue = 0; //Color.blue(test); 
      int red = 0; //Color.red(test); 
      int green = 0; // Color.green(test); 
      test = 0; 
      Log.d("lookingFor", "test: " + pixels[1]); 
      while(l < 81){ 
       tempNum = (Integer) pixels[l]; 
       Log.d("lookingFor", "Pixel Num: " + Color.blue(tempNum)); 
       tempBlue = Color.blue(tempNum); 
       tempRed = Color.red(tempNum); 
       tempGreen = Color.green(tempNum); 
       Log.d("lookingFor", "current Blue: " + tempBlue); 
       blue = blue + tempBlue; 
       Log.d("lookingFor", "added blue: " + blue); 
       red = red + tempRed; 
       green = green + tempGreen; 
       l = l + 1; //test g 

      } 
      Log.v("lookingFor", blue + " " + red + " " + green); 
      blue = blue/81; 
      red = red/81; 
      green = green/81; 

      hexValue = Integer.toHexString(test); 
      Log.d(TAG, "pixel at (" + centerX + ", " + centerY + " succesfully retreived! with value of: " + test); 

      Log.d(TAG, "and an Hex value of: " + hexValue); 
      // blue = Color.blue(test); 
      // red = Color.red(test); 
      // green = Color.green(test); 
      //this is a modification 

      Log.d(TAG, "RGB COLOR! R:" + red + " G:" + green + " B:" + blue); 
      long timeAtEnd = System.currentTimeMillis(); 
      long totalTime = timeAtEnd - timeAtStart; 
      Log.d(TAG, "Fetching the color took " + totalTime + " milliseconds"); 
      rgbDisplay.setText("R:" + red + " G:" + green + " B:" + blue); 

     } 
    }); 

    Log.d(TAG, "onCreate'd"); 
} 

ShutterCallback shutterCallback = new ShutterCallback() { 
    public void onShutter() { 
     Log.d(TAG, "onShutter'd"); 
    } 
}; 

/** Handles data for raw picture */ 
PictureCallback rawCallback = new PictureCallback() { 
    public void onPictureTaken(byte[] data, Camera camera) { 
     Log.d(TAG, "onPictureTaken - raw"); 
    } 
}; 

/** Handles data for jpeg picture */ 
PictureCallback jpegCallback = new PictureCallback() { 
    public void onPictureTaken(byte[] data, Camera camera) { 
     FileOutputStream outStream = null; 
     try { 
      // write to local sandbox file system 
      // outStream = 
      // CameraDemo.this.openFileOutput(String.format("%d.jpg", 
      // System.currentTimeMillis()), 0); 
      // Or write to sdcard 
      outStream = new FileOutputStream(String.format(
        "/sdcard/%d.jpg", System.currentTimeMillis())); 
      outStream.write(data); 
      outStream.close(); 
      Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length); 
     } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } finally { 
     } 
     Log.d(TAG, "onPictureTaken - jpeg"); 
    } 
}; 

} 

（メインjavaファイルのthats）

import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 

import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.hardware.Camera; 
import android.hardware.Camera.PreviewCallback; 
import android.util.Log; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 

class Preview extends SurfaceView implements SurfaceHolder.Callback { 
private static final String TAG = "Preview"; 

SurfaceHolder mHolder; 
public Camera camera; 

Preview(Context context) { 
    super(context); 

    // Install a SurfaceHolder.Callback so we get notified when the 
    // underlying surface is created and destroyed. 
    mHolder = getHolder(); 
    mHolder.addCallback(this); 
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 
} 

public void surfaceCreated(SurfaceHolder holder) { 
    // The Surface has been created, acquire the camera and tell it where 
    // to draw. 
    camera = Camera.open(); 
    try { 
     camera.setPreviewDisplay(holder); 

     camera.setPreviewCallback(new PreviewCallback() { 

      public void onPreviewFrame(byte[] data, Camera arg1) { 
       /*FileOutputStream outStream = null; 
       try { 
        outStream = new FileOutputStream(String.format(
          "/sdcard/%d.jpg", System.currentTimeMillis())); 
        outStream.write(data); 
        outStream.close(); 
        Log.d(TAG, "onPreviewFrame - wrote bytes: " 
          + data.length); 
       } catch (FileNotFoundException e) { 
        e.printStackTrace(); 
       } catch (IOException e) { 
        e.printStackTrace(); 
       } finally { 
       }*/ 
       Preview.this.invalidate(); 
      } 
     }); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
} 

public void surfaceDestroyed(SurfaceHolder holder) { 
    // Surface will be destroyed when we return, so stop the preview. 
    // Because the CameraDevice object is not a shared resource, it's very 
    // important to release it when the activity is paused. 
    camera.stopPreview(); 
    camera = null; 
} 

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { 
    // Now that the size is known, set up the camera parameters and begin 
    // the preview. 
    Camera.Parameters parameters = camera.getParameters(); 
    parameters.setPreviewSize(w, h); 
    camera.setParameters(parameters); 
    camera.startPreview(); 
} 

@Override 
public void draw(Canvas canvas) { 
    super.draw(canvas); 
    Paint p = new Paint(Color.RED); 
    Log.d(TAG, "draw"); 
    canvas.drawText("PREVIEW", canvas.getWidth()/2, 
      canvas.getHeight()/2, p); 
} 
} 

Answer 1

あなたのコードの平均値（コードは少し厄介である場合には申し訳ありません）カメラのプレビューまたはカメラの画像。

あなたはonPreviewFrameに渡されたバイト配列を受け取り、それをプレビューフォーマット（おそらくYUV422またはYUV420）から好みのRGBフォーマットに変換し、RGBカラーで数学を行う必要があると思います。