基于Google Vision Face Tracker的Face Tracker应用。默认情况下，脸部追踪器使用后/后相机，但我想用前置相机检测脸部。
这是Google愿景提供的CameraSourcePreview代码：
package com.google.android.gms.samples.vision.face.facetracker.ui.camera;
import android.content.Context;
import android.content.res.Configuration;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.ViewGroup;
import com.google.android.gms.common.images.Size;
import com.google.android.gms.vision.CameraSource;
import java.io.IOException;
public class CameraSourcePreview extends ViewGroup {
private static final String TAG = "CameraSourcePreview";
private Context mContext;
private SurfaceView mSurfaceView;
private boolean mStartRequested;
private boolean mSurfaceAvailable;
private CameraSource mCameraSource;
private GraphicOverlay mOverlay;
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);
}
public void start(CameraSource cameraSource) throws IOException {
if (cameraSource == null) {
stop();
}
mCameraSource = cameraSource;
if (mCameraSource != null) {
mStartRequested = true;
startIfReady();
}
}
public void start(CameraSource cameraSource, GraphicOverlay overlay) throws IOException {
mOverlay = overlay;
start(cameraSource);
}
public void stop() {
if (mCameraSource != null) {
mCameraSource.stop();
}
}
public void release() {
if (mCameraSource != null) {
mCameraSource.release();
mCameraSource = null;
}
}
private void startIfReady() throws IOException {
if (mStartRequested && mSurfaceAvailable) {
mCameraSource.start(mSurfaceView.getHolder());
if (mOverlay != null) {
Size size = mCameraSource.getPreviewSize();
int min = Math.min(size.getWidth(), size.getHeight());
int max = Math.max(size.getWidth(), size.getHeight());
if (isPortraitMode()) {
// Swap width and height sizes when in portrait, since it will be rotated by
// 90 degrees
mOverlay.setCameraInfo(min, max, mCameraSource.getCameraFacing());
} else {
mOverlay.setCameraInfo(max, min, mCameraSource.getCameraFacing());
}
mOverlay.clear();
}
mStartRequested = false;
}
}
private class SurfaceCallback implements SurfaceHolder.Callback {
@Override
public void surfaceCreated(SurfaceHolder surface) {
mSurfaceAvailable = true;
try {
startIfReady();
} catch (IOException e) {
Log.e(TAG, "Could not start camera source.", e);
}
}
@Override
public void surfaceDestroyed(SurfaceHolder surface) {
mSurfaceAvailable = false;
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
int width = 640;
int height = 480;
if (mCameraSource != null) {
Size size = mCameraSource.getPreviewSize();
if (size != null) {
width = size.getWidth();
height = size.getHeight();
}
}
// Swap width and height sizes when in portrait, since it will be rotated 90 degrees
if (isPortraitMode()) {
int tmp = width;
width = height;
height = tmp;
}
final int layoutWidth = right - left;
final int layoutHeight = bottom - top;
// Computes height and width for potentially doing fit width.
int childWidth = layoutWidth;
int childHeight = (int)(((float) layoutWidth / (float) width) * height);
// If height is too tall using fit width, does fit height instead.
if (childHeight > layoutHeight) {
childHeight = layoutHeight;
childWidth = (int)(((float) layoutHeight / (float) height) * width);
}
for (int i = 0; i < getChildCount(); ++i) {
getChildAt(i).layout(0, 0, childWidth, childHeight);
}
try {
startIfReady();
} catch (IOException e) {
Log.e(TAG, "Could not start camera source.", e);
}
}
private boolean isPortraitMode() {
int orientation = mContext.getResources().getConfiguration().orientation;
if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
return false;
}
if (orientation == Configuration.ORIENTATION_PORTRAIT) {
return true;
}
Log.d(TAG, "isPortraitMode returning false by default");
return false;
}
}
我用这种方法调用相机源：
private void startCameraSource() {
// check that the device has play services available.
int code = GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(
getApplicationContext());
if (code != ConnectionResult.SUCCESS) {
Dialog dlg =
GoogleApiAvailability.getInstance().getErrorDialog(this, code, RC_HANDLE_GMS);
dlg.show();
}
if (mCameraSource != null) {
try {
mPreview.start(mCameraSource, mGraphicOverlay);
} catch (IOException e) {
Log.e(TAG, "Unable to start camera source.", e);
mCameraSource.release();
mCameraSource = null;
}
}
}
与默认手机相机应用程序相比，Face Tracker前置摄像头仍然太暗。
如何在脸部追踪器谷歌愿景中照亮前置摄像头？它与表面视图有关吗？
<com.google.android.gms.samples.vision.face.facetracker.ui.camera.CameraSourcePreview
android:id="@+id/preview"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1.00"
android:weightSum="1">
<com.google.android.gms.samples.vision.face.facetracker.ui.camera.GraphicOverlay
android:id="@+id/faceOverlay"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.79" />
</com.google.android.gms.samples.vision.face.facetracker.ui.camera.CameraSourcePreview>
答案 0 :(得分：1)
它根本与SurfaceView无关。这是Camera API配置错误。您必须在CameraSource.java文件中进行一些其他更改。 您可以在this GitHub repository
上找到它首先，您需要知道这是一个曝光问题。它指的是相机允许在镜头上接收的光线。您需要知道您的相机是否支持曝光补偿。您必须从Camera.Parameters实例中查询getMinExposureCompensation()和getMaxExposureCompensation()。正如文档所解释的那样，如果两种方法都返回0，则不支持曝光补偿，并且您无能为力。
幸运的是，大多数时候所有手机都支持这一特性。现在，您可以通过调用getExposureCompensation()来检查当前的相机曝光，这将返回默认值（通常为0，这意味着不调整曝光）。现在以防止黑暗图像，您只需使用setExposureCompensation()在最小值和最大值之间设置新曝光，然后将Camera.Parameters应用到相机。
最后，您可以使用setAutoExposureLock()，getAutoExposureLock()锁定曝光以避免丢失配置，最重要的是：在设置曝光锁定之前，您必须确保isAutoExposureLockSupported()返回true。 / p>
祝你好运！