Question

我正在使用我的Android相机进行一些图像处理。它采用NV21格式的原始数据，然后将其转换为RGB格式，以获得每帧的平均R值。帧速率设置为16，具有最佳的手机分辨率。有很多转换算法，而我使用的算法效果很好。然而，我坚持的问题是我想绘制一个R值对时间的图形，因为我在onPreviewFrame中调用转换，我无法弄清楚如何从这个方法获取R的值我可以执行图处理的主要活动。

我的相机类的onPreviewMethod是：

@Override
public void onPreviewFrame(byte[] data, Camera camera){

    //check if data is null
    if (data == null)
        throw new NullPointerException();

    Camera.Size size = camera.getParameters().getPreviewSize();

    //check if size is null
    if(size == null)
        throw new NullPointerException();


    //set resolution of camera view to optimal setting
    int width = size.width;
    int height = size.height;
    Log.d("Resolution ", " "+String.valueOf(width)+" "+String.valueOf(height));


    //call ImageProcess on the data to decode YUV420SP to RGB
    imgAvg = ImageProcessing.decodeYUV420SPtoRedAvg(data, width, height);
    imageIntensity = imgAvg/255;

    //set value of Y on the text view
    TextView valueOfY = (TextView)getRootView().findViewById(R.id.valueY);
    valueY = imgAvg;
    valueOfY.setText(Double.toString(imgAvg));

}

在这里 imgAvg 变量存储每个帧的平均R值。日志显示正确的结果，每秒有16个结果。我想从我正在绘制图表的主要活动中访问此数据。这样做的正确方法是什么？我可以以某种方式直接访问这些数据，或者我是否需要以某种形式存储数据然后从另一个活动访问它。（N.B我想避免保存整个视频并进行图像处理。）谢谢。

Answer 1

示例：

public class Camera {

public interface PreviewReadyCallback {
  void onPreviewFrame(String value1, int value2, Double value3, Float value4, Bitmap value5); // Any value you want to get
}




PreviewReadyCallback mPreviewReadyCallback = null;

public void setOnPreviewReady(PreviewReadyCallback cb) {
    mPreviewReadyCallback = cb;
}

@Override
public void onPreviewFrame(byte[] data, Camera camera){

//check if data is null
if (data == null)
    throw new NullPointerException();

Camera.Size size = camera.getParameters().getPreviewSize();

//check if size is null
if(size == null)
    throw new NullPointerException();


//set resolution of camera view to optimal setting
int width = size.width;
int height = size.height;
Log.d("Resolution ", " "+String.valueOf(width)+" "+String.valueOf(height));


//call ImageProcess on the data to decode YUV420SP to RGB
imgAvg = ImageProcessing.decodeYUV420SPtoRedAvg(data, width, height);
imageIntensity = imgAvg/255;

//set value of Y on the text view
TextView valueOfY = (TextView)getRootView().findViewById(R.id.valueY);
valueY = imgAvg;
valueOfY.setText(Double.toString(imgAvg));
mPreviewReadyCallback.onPreviewFrame(value1, value2, value3, value4, value5);

} 
}

在YourActivity中

public class YourActivity extends Activity implements PreviewReadyCallback{
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Camera camera = new Camera();
     camera.setOnPreviewReady(this);
}
@Override
public void onPreviewFrame(String value1, int value2, Double value3, Float value4, Bitmap value5) {

  // Code here!

   }
 }

将来自java类内的onPreviewFrame的数据转换为另一个活动：Android

1 个答案: