从 com.google.android.gms.vision.CameraSource 和 Increasing/Decreasing 预览亮度访问相机

Question

我必须在 Google Vision API 的 CameraSource 中实现以构建相机并在捕获图像之前进行人脸检测。现在我遇到了一些问题，所以我需要从 CameraSource 访问相机对象。

如何使用 CameraSource 增加或减少相机预览亮度？

这是我的 CameraSource Builder

 mCameraSource = new CameraSource.Builder(context, detector)
                .setRequestedPreviewSize(640, 480)
                .setFacing(CameraSource.CAMERA_FACING_FRONT)
                .setRequestedFps(30.0f)
                .build();

这里我必须尝试 access/get 来自 mCameraSource 对象的相机。

Field[] declaredFields = CameraSource.class.getDeclaredFields();

        for (Field field : declaredFields) {
            if (field.getType() == Camera.class) {
                field.setAccessible(true);
                try {
                    Camera camera = (Camera) field.get(mCameraSource);
                    if (camera != null) {
                        Camera.Parameters params = camera.getParameters();                        
                        params.setExposureCompensation(1500);
                        camera.setParameters(params);
                    }
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }

            }
        }

但 camera returns 仅空，我的第二个问题是如何进行亮度选项...

if (camera != null) {
     Camera.Parameters params = camera.getParameters();                        
     params.setExposureCompensation(1500);
     camera.setParameters(params);
 }

Answer 1

我必须这样实现我的目标，

相机亮度级别是-12到12。所以最小亮度级别是-12，最大亮度级别是12。

现在我必须自定义 CameraSourcePreview 构造函数，例如

private int defaultBrightness = 12;

public CameraSourcePreview(Context context, AttributeSet attrs) {
    super(context, attrs);
    mContext = context;
    mStartRequested = false;
    mSurfaceAvailable = false;

    mSurfaceView = new SurfaceView(context);
    mSurfaceView.getHolder().addCallback(new SurfaceCallback());
    addView(mSurfaceView);
    mSurfaceView.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            cameraFocus(mCameraSource, brightness);
        }
    });
}

private static boolean cameraFocus(@NonNull CameraSource cameraSource, int brightness) {
    Field[] declaredFields = CameraSource.class.getDeclaredFields();

    for (Field field : declaredFields) {
        if (field.getType() == Camera.class) {
            field.setAccessible(true);
            try {
                Camera camera = (Camera) field.get(cameraSource);
                if (camera != null) {
                    Camera.Parameters params = camera.getParameters();
                        params.setExposureCompensation(brightness);
                    camera.setParameters(params);
                    return true;
                }

                return false;
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }

            break;
        }
    }

    return false;
}

然后我要通过seekbar实现动态亮度调节

喜欢

seekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {


                cameraFocus(mCameraSource,i-12);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
            }
        });

搜索栏xml代码

<SeekBar
            android:id="@+id/seekBar1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:max="24"
            android:layout_gravity="center_vertical"/>

终于，我得到了解决方案...:)

从 com.google.android.gms.vision.CameraSource 和 Increasing/Decreasing 预览亮度访问相机

Accessing the Camera from com.google.android.gms.vision.CameraSource and Increasing/Decreasing the Preview Brightness

java

camera

android

surfaceview

vision-api