没有关于camera2面部检测机制的足够信息。我使用了Google的Camera2示例：https://github.com/android/camera-samples
我将面部检测模式设置为FULL。
mPreviewRequestBuilder.set(CaptureRequest.STATISTICS_FACE_DETECT_MODE,
CameraMetadata.STATISTICS_FACE_DETECT_MODE_FULL);
我也检查过
[STATISTICS_INFO_MAX_FACE_COUNT和STATISTICS_INFO_AVAILABLE_FACE_DETECT_MODES：
int max_count = characteristics.get(
CameraCharacteristics.STATISTICS_INFO_MAX_FACE_COUNT);
int modes [] = characteristics.get(
CameraCharacteristics.STATISTICS_INFO_AVAILABLE_FACE_DETECT_MODES);
输出：maxCount：5，模式：[0，2]
我的CaptureCallback：
private CameraCaptureSession.CaptureCallback mCaptureCallback
= new CameraCaptureSession.CaptureCallback() {
private void process(CaptureResult result) {
Integer mode = result.get(CaptureResult.STATISTICS_FACE_DETECT_MODE);
Face [] faces = result.get(CaptureResult.STATISTICS_FACES);
if(faces != null && mode != null)
Log.e("tag", "faces : " + faces.length + " , mode : " + mode );
}
@Override
public void onCaptureProgressed(CameraCaptureSession session, CaptureRequest request,
CaptureResult partialResult) {
process(partialResult);
}
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request,
TotalCaptureResult result) {
process(result);
}
输出：面孔：0，模式：2
public static final int STATISTICS_FACE_DETECT_MODE_FULL = 2;
脸部长度始终为0。看起来无法正确检测到脸部或我错过了某些东西。
我知道使用FaceDetector的方法。我只是想检查一下它在新的camera2 Face中如何工作。
我的尝试是在android 5.0（API 21）上进行的。更新到5.1（API 22）后，它开始工作，无需更改代码。
https://github.com/rajktariya/Android-Camera2-Front-with-Face-Detection
找到带有面部检测功能的两个前置摄像头的工作样本
我发现只有在使用STATE_PREVIEW的情况下，您才能处理结果以显示人脸长。 Change from
private CameraCaptureSession.CaptureCallback mCaptureCallback
= new CameraCaptureSession.CaptureCallback() {
private void process(CaptureResult result) {
Integer mode = result.get(CaptureResult.STATISTICS_FACE_DETECT_MODE);
Face[] faces = result.get(CaptureResult.STATISTICS_FACES);
if(faces != null && mode != null) {
Log.e("tag", "faces : " + faces.length + " , mode : " + mode);
}
switch (mState) {
case STATE_PREVIEW: {
// We have nothing to do when the camera preview is working normally.
break;
}
...
to
private CameraCaptureSession.CaptureCallback mCaptureCallback
= new CameraCaptureSession.CaptureCallback() {
private void process(CaptureResult result) {
switch (mState) {
case STATE_PREVIEW: {
Face[] faces = result.get(CaptureResult.STATISTICS_FACES);
if (faces != null && faces.length > 0) {
Log.e("tag", "faces : " + faces.length);
}
break;
}
请尝试此操作以查看是否有效。
我认为您的手机在使用Google Face检测时效果不佳。您确定它使用HAL3并且可以使用API2吗？]
例如，在我的代码中，我正在使用人脸检测，而没有这样的问题：
private CameraCaptureSession.CaptureCallback mPhotoCaptureCallback
= new CameraCaptureSession.CaptureCallback() {
//more code...
private void process(CaptureResult result) {
switch (mState) {
case STATE_PREVIEW: {
checkFaces(result.get(CaptureResult.STATISTICS_FACES));
//more code....
break;
}
//more code...
}
这里是checkFaces方法：
private void checkFaces(Face[] faces) {
if (faces != null) {
CameraUtil.CustomFace[] mMappedCustomFaces;
mMappedCustomFaces = computeFacesFromCameraCoordinates(faces);
if (faces != null && faces.length > 0) {
mHandler.sendEmptyMessage(SHOW_FACES_MSG);
mLastTimeRenderingFaces = System.currentTimeMillis();
}
} else {
if (System.currentTimeMillis() > (mLastTimeRenderingFaces + 100)) {
mHandler.sendEmptyMessage(HIDE_FACES_MSG);
}
}
}
我的自定义Face类：
// public static class CustomFace extends Camera.CustomFace{
public static class CustomFace {
private int score = 0;
private Rect rect = null;
public CustomFace(Rect rect, int score) {
this.score = score;
this.rect = rect;
}
public int getScore() {
return score;
}
public Rect getBounds() {
return rect;
}
}
最后使用此方法，您可以正确绘制面孔（可以使用默认的android面孔，但是矩形在4：3或16：9尺寸或旋转手机时效果不佳：
public static RectF rectToRectF(Rect r) {
return new RectF(r.left, r.top, r.right, r.bottom);
}
private CameraFaceUtil.CustomFace[] computeFacesFromCameraCoordinates(Face[] faces) {
CameraFaceUtil.CustomFace[] mappedFacesList = new CameraFaceUtil.CustomFace[faces.length];
mCameraCharacteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);
float toStandardAspectRatio = ((float) mPreviewRect.bottom / (float) mPreviewRect.right) / AutoFitTextureView.RATIO_STANDARD;
//
for (int i = 0; i < faces.length; i++) {
RectF mappedRect = new RectF();
Log.i(TAG, "[computeFacesFromCameraCoordinates] toStandardAspectRatio: " + toStandardAspectRatio);
Log.i(TAG, "[computeFacesFromCameraCoordinates] preview rect: " + mPreviewRect);
Log.i(TAG, "[computeFacesFromCameraCoordinates] raw rect: " + faces[i].getBounds());
mCameraToPreviewMatrix.mapRect(mappedRect, CameraUtil.rectToRectF(faces[i].getBounds()));
Log.i(TAG, "[computeFacesFromCameraCoordinates] mapped rect: " + mappedRect);
Rect auxRect = new Rect(CameraUtil.rectFToRect(mappedRect));
Log.i(TAG, "[computeFacesFromCameraCoordinates] aux rect: " + auxRect);
int cameraSensorOrientation = mCameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
Log.i(TAG, "[computeFacesFromCameraCoordinates] cameraSensorOrientation: " + cameraSensorOrientation);
switch (cameraSensorOrientation) {
case 90:
mappedRect.top = auxRect.left;
mappedRect.bottom = auxRect.right;
mappedRect.left = (mPreviewRect.right - auxRect.bottom);
mappedRect.right = (mPreviewRect.right - auxRect.top);
break;
case 180:
mappedRect.top = (mPreviewRect.bottom - auxRect.bottom) * toStandardAspectRatio;
mappedRect.bottom = (mPreviewRect.bottom - auxRect.top) * toStandardAspectRatio;
mappedRect.left = (mPreviewRect.right - auxRect.right) * toStandardAspectRatio;
mappedRect.right = (mPreviewRect.right - auxRect.left) * toStandardAspectRatio;
break;
case 270:
mappedRect.top = (mPreviewRect.bottom - auxRect.right) * toStandardAspectRatio;
mappedRect.bottom = (mPreviewRect.bottom - auxRect.left) * toStandardAspectRatio;
mappedRect.left = auxRect.top;
mappedRect.right = auxRect.bottom;
break;
}
Log.i(TAG, "[computeFacesFromCameraCoordinates] rotated by camera driver orientation rect without scale: "
+ mappedRect + ", with score: " + faces[i].getScore());
float topOffset = mappedRect.top;
float leftOffset = mappedRect.left;
mappedRect.top = mappedRect.top * toStandardAspectRatio;
mappedRect.bottom = mappedRect.bottom * toStandardAspectRatio;
mappedRect.left = mappedRect.left * toStandardAspectRatio;
mappedRect.right = mappedRect.right * toStandardAspectRatio;
Log.i(TAG, "[computeFacesFromCameraCoordinates] rotated by camera driver orientation rect with scale: "
+ mappedRect + ", with score: " + faces[i].getScore());
topOffset = mappedRect.top - topOffset;
leftOffset = mappedRect.left - leftOffset;
mappedRect.top -= topOffset /*- (mMirror ? mPreviewRect.height() : 0)*/;
mappedRect.bottom -= topOffset /* - (mMirror ? mPreviewRect.height() : 0)*/;
mappedRect.left -= leftOffset;
mappedRect.right -= leftOffset;
Log.i(TAG, "[computeFacesFromCameraCoordinates] rotated by camera driver orientation rect with offset: "
+ mappedRect + " topOffset " + topOffset + " leftOffset " + leftOffset);
// set the new values to the mapping array to get rendered
mappedFacesList[i] = new CameraFaceUtil.CustomFace(CameraUtil.rectFToRect(mappedRect), faces[i].getScore());
}
return mappedFacesList;
}
我正在做的是根据屏幕比例和大小绘制面孔。随时询问您是否需要有关camera2API的其他信息。