坏像素化图像 - 自定义 android 相机

Posted 2023-04-17

【中文标题】坏像素化图像 - 自定义 android 相机

【英文标题】：Bad pixelated image - custom android camera

【发布时间】：2015-12-19 21:32:25

【问题描述】：

我制作了自己的定制相机。这给了我糟糕的像素化图像，我不知道为什么。我使用 JPEG 压缩质量为 100。这是我得到的图像 Camera picture

这是我的代码：

public class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback 
private SurfaceHolder mHolder;
private Context mContext;
private Camera.Parameters parameters;
private byte[] mBuffer;

public CameraSurfaceView(Context context) 
    super(context);
    mContext = context;
    mHolder = getHolder();
    mHolder.addCallback(this);
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);


public void surfaceCreated(SurfaceHolder holder) 
    // The Surface has been created, now tell the camera where to draw the preview.
    try 
        if (CameraConfigurationUtils.mCameraInstance != null) 
            CameraConfigurationUtils.mCameraInstance.setDisplayOrientation(90);
            CameraConfigurationUtils.mCameraInstance.setPreviewDisplay(holder);
            parameters = CameraConfigurationUtils.mCameraInstance.getParameters();
            if (android.os.Build.VERSION.SDK_INT >= 14) 
                CameraConfigurationUtils.setFocus(parameters, true, true, false);
             else 
                CameraConfigurationUtils.setFocus(parameters, true, true, true);
            
            WindowManager manager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
            Display display = manager.getDefaultDisplay();
            Point theScreenResolution = new Point();
            theScreenResolution.set(display.getHeight(), display.getWidth());
            CameraConfigurationUtils.findBestPreviewSizeValue(parameters, theScreenResolution);
            CameraConfigurationUtils.mCameraInstance.setParameters(parameters);
            updateBufferSize();
            CameraConfigurationUtils.mCameraInstance.addCallbackBuffer(mBuffer);
            CameraConfigurationUtils.mCameraInstance.setPreviewCallbackWithBuffer(new Camera.PreviewCallback() 
                public synchronized void onPreviewFrame(byte[] data, Camera c) 
                    if (CameraConfigurationUtils.mCameraInstance != null) 
                        CameraConfigurationUtils.mCameraInstance.addCallbackBuffer(mBuffer);
                    
                
            );
            CameraConfigurationUtils.startPreview(mContext);
        
     catch (IOException e) 
        e.printStackTrace();
        CameraConfigurationUtils.releaseCamera();
    



public void surfaceDestroyed(SurfaceHolder holder) 
    mHolder.removeCallback(this);
    CameraConfigurationUtils.stopPreview();


public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) 
    if (mHolder.getSurface() == null) 
        return;
    
    try 
        CameraConfigurationUtils.mCameraInstance.setPreviewDisplay(mHolder);
        CameraConfigurationUtils.startPreview(mContext);
     catch (Exception e) 
        CameraConfigurationUtils.releaseCamera();
    


public byte[] getPic(int x, int y, int width, int height) 
    System.gc();
    Camera.Size s = parameters.getPreviewSize();
    YuvImage yuvimage = new YuvImage(mBuffer, ImageFormat.NV21, s.width, s.height, null);
    ByteArrayOutputStream outStream = new ByteArrayOutputStream();
    yuvimage.compressToJpeg(new Rect(x, y, width, height), 100, outStream); // make JPG

    yuvimage = null;
    System.gc();
    return outStream.toByteArray();


private void updateBufferSize() 
    mBuffer = null;
    System.gc();
    // prepare a buffer for copying preview data to
    int h = parameters.getPreviewSize().height;
    int w = parameters.getPreviewSize().width;
    int bitsPerPixel = ImageFormat.getBitsPerPixel(parameters.getPreviewFormat());
    mBuffer = new byte[w * h * bitsPerPixel / 8];
    //Log.i("surfaceCreated", "buffer length is " + mBuffer.length + " bytes");

我做错了什么？

【参考方案1】：

您的图片示例看起来就像来自相机的常规低分辨率预览图像，但我可以看到在高分辨率屏幕中它会显示像素化。我相信你的问题在于这部分代码：

CameraConfigurationUtils.findBestPreviewSizeValue(parameters, theScreenResolution);
CameraConfigurationUtils.mCameraInstance.setParameters(parameters);

您似乎只是在计算最佳预览尺寸，该尺寸正在返回给您，但您并未将其设置为实际预览尺寸。试试这样：

Point bestPreviewSize = CameraConfigurationUtils.findBestPreviewSizeValue(parameters, theScreenResolution);
parameters.setPreviewSize(bestPreviewSize.x, bestPreviewSize.y);
CameraConfigurationUtils.mCameraInstance.setParameters(parameters);

另一件事是，如果您打算拍摄高分辨率图片，则不应使用 getPic() 方法，因为它只是将预览帧作为 jpeg 获取，这是较低分辨率的图像。您应该为此查看Camera#takePicture method。