Android原生人脸识别Camera2示例
景嘉志
1. 简介
Camera2 是最新的低级 Android 相机包，取代了已弃用的Camera类。Camera2 为复杂的用例提供了深入的控制，但需要您管理特定于设备的配置。源码地址
2. Camera2相机开发流程总结
1.检测并访问相机资源：检查手机是否存在相机资源，如果存在则请求访问相机资源。
2.创建预览界面：创建继承自SurfaceView并实现SurfaceHolder接口的拍摄预览类。有了拍摄预览类，即可创建一个布局文件，将预览画面与设计好的用户界面控件融合在一起，实时显示相机的预览图像。
3.设置拍照监听器：给用户界面控件绑定监听器，使其能响应用户操作, 开始拍照过程。
4.拍照并保存文件：将拍摄获得的图像转换成位图文件，最终输出保存成各种常用格式的图片。
5.释放相机资源：相机是一个共享资源，当相机使用完毕后，必须正确地将其释放，以免其它程序访问使用时发生冲突。
3. Camera2消息流转
1.由SystemService创建CameraManager；
2.整个camera2由CameraManager来进行统一管理；
3.CameraManager通过CameraDevice、CameraCharacteristic和CameraCaptureSession对Camera进行操作；
4.CameraDevice和CameraCaptureSession都有回调函数完成相关操作，包括相机打开，capture过程处理，capture完成处理等。
5.Android设备发送CameraCaptureRequest给Camera，而Camera处理完后发送元数据CameraMetaData给Android设备。
4. 示例类
4.1 Camera2Utils
package com.zw.camera2test.camera2;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.ImageFormat;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.CaptureResult;
import android.hardware.camera2.TotalCaptureResult;
import android.hardware.camera2.params.Face;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.media.Image;
import android.media.ImageReader;
import android.os.Build;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Log;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.Surface;
import android.view.TextureView;
import android.view.WindowManager;
import androidx.annotation.RequiresApi;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class Camera2Utils {
private static final String TAG = "Camera2Utils";
private static Camera2Utils mCameraUtils;
private CameraManager cManager;
private Size cPixelSize;//相机成像尺寸
private int cOrientation;
private Size captureSize;
private int[] faceDetectModes;
private TextureView cView;//用于相机预览
private Surface previewSurface;//预览Surface
private ImageReader cImageReader;
private Surface captureSurface;//拍照Surface
HandlerThread cHandlerThread;//相机处理线程
Handler cHandler;//相机处理
CameraDevice cDevice;
CameraCaptureSession cSession;
CameraDevice.StateCallback cDeviceOpenCallback = null;//相机开启回调
CaptureRequest.Builder previewRequestBuilder;//预览请求构建
CaptureRequest previewRequest;//预览请求
CameraCaptureSession.CaptureCallback previewCallback;//预览回调
CaptureRequest.Builder captureRequestBuilder;
CaptureRequest captureRequest;
CameraCaptureSession.CaptureCallback captureCallback;
private Context mContext;
WindowManager mWindowManager;
//为了使照片竖直显示
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
static {
ORIENTATIONS.append(Surface.ROTATION_0, 90);
ORIENTATIONS.append(Surface.ROTATION_90, 0);
ORIENTATIONS.append(Surface.ROTATION_180, 270);
ORIENTATIONS.append(Surface.ROTATION_270, 180);
}
public static Camera2Utils getInstance() {
if (mCameraUtils == null) {
synchronized (Camera2Utils.class) {
if (mCameraUtils == null) {
mCameraUtils = new Camera2Utils();
}
}
}
return mCameraUtils;
}
public void init(WindowManager windowManager, Context context, TextureView textureView) {
this.mWindowManager = windowManager;
this.mContext = context;
this.cView = textureView;
}
@SuppressLint("MissingPermission")
public void startPreview() {
boolean isFront = true;
//前置摄像头
String cId = "";
if (isFront) {
cId = CameraCharacteristics.LENS_FACING_BACK + "";
} else {
cId = CameraCharacteristics.LENS_FACING_FRONT + "";
}
cManager = (CameraManager) mContext.getSystemService(Context.CAMERA_SERVICE);
//根据摄像头ID，开启摄像头
try {
//获取开启相机的相关参数
CameraCharacteristics characteristics = cManager.getCameraCharacteristics(cId);
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
Size[] previewSizes = map.getOutputSizes(SurfaceTexture.class);//获取预览尺寸
Size[] captureSizes = map.getOutputSizes(ImageFormat.JPEG);//获取拍照尺寸
cOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);//获取相机角度
Rect cRect = characteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);//获取成像区域
cPixelSize = characteristics.get(CameraCharacteristics.SENSOR_INFO_PIXEL_ARRAY_SIZE);//获取成像尺寸，同上
Log.i(TAG, "获取相机角度 : " + cOrientation);
//可用于判断是否支持人脸检测，以及支持到哪种程度
faceDetectModes = characteristics.get(CameraCharacteristics
.STATISTICS_INFO_AVAILABLE_FACE_DETECT_MODES);//支持的人脸检测模式
int maxFaceCount = characteristics.get(CameraCharacteristics.STATISTICS_INFO_MAX_FACE_COUNT);
int mFaceDetectMode = CaptureRequest.STATISTICS_FACE_DETECT_MODE_OFF;
for (int i = 0; i < faceDetectModes.length; i++) {
int face = faceDetectModes[i];
if (face == CaptureRequest.STATISTICS_FACE_DETECT_MODE_FULL || face == CaptureRequest.STATISTICS_FACE_DETECT_MODE_SIMPLE) {
Log.i(TAG, "相机硬件不支持人脸检测---" + face);
mFaceDetectMode = CaptureRequest.STATISTICS_FACE_DETECT_MODE_FULL;
break;
}
}
if (mFaceDetectMode == CaptureRequest.STATISTICS_FACE_DETECT_MODE_OFF) {
Log.i(TAG, "相机硬件不支持人脸检测");
return;
}
//支持的最大检测人脸数量
//此处写死640*480，实际从预览尺寸列表选择
// previewSizes[2];
Size sSize = new Size(640, 480);
//设置预览尺寸（避免控件尺寸与预览画面尺寸不一致时画面变形）
transformImage(previewSizes, cView.getWidth(), cView.getHeight());
cView.getSurfaceTexture().setDefaultBufferSize(sSize.getWidth(), sSize.getHeight());
cManager.openCamera(cId, getCDeviceOpenCallback(), getCHandler());
} catch (CameraAccessException e) {
}
}
private void transformImage(Size[] previewSizes, int width, int height) {
Size mPreviewSize = getOptimalSize(previewSizes, width, height);
if (mPreviewSize == null || cView == null) {
return;
}
Matrix matrix = new Matrix();
int rotation = mWindowManager.getDefaultDisplay().getRotation();
RectF textureRectF = new RectF(0, 0, width, height);
RectF previewRectF = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth());
float centerX = textureRectF.centerX();
float centery = textureRectF.centerY();
if (rotation == Surface.ROTATION_0 || rotation == Surface.ROTATION_270) {
} else if (rotation == Surface.ROTATION_90 || rotation == Surface.ROTATION_270) {
previewRectF.offset(centerX - previewRectF.centerX(), centery - previewRectF.centerY());
matrix.setRectToRect(textureRectF, previewRectF, Matrix.ScaleToFit.FILL);
float scale = Math.max((float) width / mPreviewSize.getWidth(), (float) height / mPreviewSize.getHeight());
matrix.postScale(scale, scale, centerX, centery);
matrix.postRotate(90 * (rotation - 2), centerX, centery);
cView.setTransform(matrix);
}
}
/**
* 解决预览变形问题
*
* @param sizeMap
* @param width
* @param height
* @return
*/
//选择sizeMap中大于并且最接近width和height的size
private Size getOptimalSize(Size[] sizeMap, int width, int height) {
List<Size> sizeList = new ArrayList<>();
for (Size option : sizeMap) {
if (width > height) {
if (option.getWidth() > width && option.getHeight() > height) {
sizeList.add(option);
}
} else {
if (option.getWidth() > height && option.getHeight() > width) {
sizeList.add(option);
}
}
}
if (sizeList.size() > 0) {
return Collections.min(sizeList, new Comparator<Size>() {
@Override
public int compare(Size lhs, Size rhs) {
return Long.signum(lhs.getWidth() * lhs.getHeight() - rhs.getWidth() * rhs.getHeight());
}
});
}
return sizeMap[0];
}
private Size getOptimalPreviewSize(Size[] sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) w / h;
if (sizes == null) return null;
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Try to find an size match aspect ratio and size
Size size = null;
for (int i = 0; i < sizes.length; i++) {
size = sizes[i];
double ratio = (double) size.getWidth() / size.getHeight();
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
if (Math.abs(size.getHeight() - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.getHeight() - targetHeight);
}
}
// Cannot find the one match the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (int i = 0; i < sizes.length; i++) {
size = sizes[i];
if (Math.abs(size.getHeight() - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.getHeight() - targetHeight);
}
}
}
return optimalSize;
}
private void configureTransform(int viewWidth, int viewHeight) {
int rotation = 1;
Matrix matrix = new Matrix();
RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
float centerX = viewRect.centerX();
float centerY = viewRect.centerY();
if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
// matrix.postScale(scale, scale, centerX, centerY);
matrix.postRotate(90 * (rotation - 2), centerX, centerY);
} else if (Surface.ROTATION_180 == rotation) {
matrix.postRotate(180, centerX, centerY);
}
cView.setTransform(matrix);
}
/**
* 初始化并获取相机开启回调对象。当准备就绪后，发起预览请求
*/
@SuppressLint("NewApi")
private CameraDevice.StateCallback getCDeviceOpenCallback() {
if (cDeviceOpenCallback == null) {
cDeviceOpenCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice camera) {//打开摄像头
cDevice = camera;
try {
//创建Session，需先完成画面呈现目标（此处为预览和拍照Surface）的初始化
camera.createCaptureSession(Arrays.asList(getPreviewSurface(), getCaptureSurface()), new
CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(CameraCaptureSession session) {
cSession = session;
//构建预览请求，并发起请求
Log.i(TAG, "[发出预览请求]");
try {
session.setRepeatingRequest(getPreviewRequest(), getPreviewCallback(),
getCHandler());
} catch (CameraAccessException e) {
Log.i(TAG, "--" + e.getMessage());
}
}
@Override
public void onConfigureFailed(CameraCaptureSession session) {
session.close();
}
}, getCHandler());
} catch (CameraAccessException e) {
Log.i(TAG, "--" + e.getMessage());
}
}
@Override
public void onDisconnected(CameraDevice camera) {
//关闭摄像头
camera.close();
}
@Override
public void onError(CameraDevice camera, int error) {
//发生错误
camera.close();
}
};
}
return cDeviceOpenCallback;
}
/**
* 初始化并获取相机线程处理
*
* @return
*/
private Handler getCHandler() {
if (cHandler == null) {
//单独开一个线程给相机使用
cHandlerThread = new HandlerThread("cHandlerThread");
cHandlerThread.start();
cHandler = new Handler(cHandlerThread.getLooper());
}
return cHandler;
}
/**
* 获取支持的最高人脸检测级别
*
* @return
*/
private int getFaceDetectMode() {
if (faceDetectModes == null) {
Log.i(TAG, "getFaceDetectMode: ----");
return CaptureRequest.STATISTICS_FACE_DETECT_MODE_FULL;
} else {
Log.i(TAG, "getFaceDetectMode: --2--" + faceDetectModes[faceDetectModes.length - 1]);
return faceDetectModes[faceDetectModes.length - 1];
}
}
/**
* 初始化并获取预览回调对象
*
* @return
*/
@SuppressLint("NewApi")
private CameraCaptureSession.CaptureCallback getPreviewCallback() {
if (previewCallback == null) {
previewCallback = new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest
request, TotalCaptureResult result) {
onCameraImagePreviewed(result);
}
};
}
return previewCallback;
}
/**
* 生成并获取预览请求
*
* @return
*/
@SuppressLint("NewApi")
private CaptureRequest getPreviewRequest() {
previewRequest = getPreviewRequestBuilder().build();
return previewRequest;
}
/**
* 初始化并获取预览请求构建对象，进行通用配置，并每次获取时进行人脸检测级别配置
*
* @return
*/
@SuppressLint("NewApi")
private CaptureRequest.Builder getPreviewRequestBuilder() {
if (previewRequestBuilder == null) {
try {
previewRequestBuilder = cSession.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
previewRequestBuilder.addTarget(getPreviewSurface());
previewRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);//自动曝光、白平衡、对焦
} catch (CameraAccessException e) {
Log.i(TAG, "--" + e.getMessage());
}
}
// previewRequestBuilder.set(CaptureRequest.STATISTICS_FACE_DETECT_MODE, getFaceDetectMode());//设置人脸检测级别
previewRequestBuilder.set(CaptureRequest.STATISTICS_FACE_DETECT_MODE, CameraCharacteristics.STATISTICS_FACE_DETECT_MODE_SIMPLE);//设置人脸检测级别
previewRequestBuilder.set(CaptureRequest.JPEG_ORIENTATION, 0);
return previewRequestBuilder;
}
/**
* 获取预览Surface
*
* @return
*/
private Surface getPreviewSurface() {
if (previewSurface == null) {
previewSurface = new Surface(cView.getSurfaceTexture());
}
return previewSurface;
}
/**
* 处理相机画面处理完成事件，获取检测到的人脸坐标，换算并绘制方框
*
* @param result
*/
@SuppressLint({"NewApi", "LocalSuppress"})
private void onCameraImagePreviewed(CaptureResult result) {
Face faces[] = result.get(CaptureResult.STATISTICS_FACES);
Log.i(TAG, "检测到有人脸，进行拍照操作：faceLength=" + faces.length);
if (faces.length > 0) {
Log.i(TAG, "检测到有人脸，-----------------------------------");
//检测到有人脸，控制相机进行拍照操作
executeCapture();
}
}
/**
* 初始化拍照相关
*/
@SuppressLint("NewApi")
private Surface getCaptureSurface() {
if (cImageReader == null) {
cImageReader = ImageReader.newInstance(getCaptureSize().getWidth(), getCaptureSize().getHeight(),
ImageFormat.JPEG, 2);
cImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader reader) {
//拍照最终回调
onCaptureFinished(reader);
}
}, getCHandler());
captureSurface = cImageReader.getSurface();
}
return captureSurface;
}
/**
* 获取拍照尺寸
*
* @return
*/
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
private Size getCaptureSize() {
if (captureSize != null) {
return captureSize;
} else {
return new Size(cView.getWidth(), cView.getHeight());
}
}
/**
* 执行拍照
*/
@SuppressLint("NewApi")
private void executeCapture() {
try {
Log.i(TAG, "发出请求");
cSession.capture(getCaptureRequest(), getCaptureCallback(), getCHandler());
} catch (CameraAccessException e) {
Log.i(TAG, "--" + e.getMessage());
}
}
@SuppressLint("NewApi")
private CaptureRequest getCaptureRequest() {
captureRequest = getCaptureRequestBuilder().build();
return captureRequest;
}
@SuppressLint("NewApi")
private CaptureRequest.Builder getCaptureRequestBuilder() {
if (captureRequestBuilder == null) {
try {
captureRequestBuilder = cSession.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
//设置拍照回调接口
captureRequestBuilder.addTarget(getCaptureSurface());
//TODO 1 照片旋转
// int rotation =getWindowManager().getDefaultDisplay().getRotation();
int rotation = 0;
int rotationTo = getOrientation(rotation);
captureRequestBuilder.set(CaptureRequest.JPEG_ORIENTATION, rotationTo);
} catch (CameraAccessException e) {
Log.i(TAG, "--" + e.getMessage());
}
}
return captureRequestBuilder;
}
@SuppressLint("NewApi")
private CameraCaptureSession.CaptureCallback getCaptureCallback() {
if (captureCallback == null) {
captureCallback = new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest
request, TotalCaptureResult result) {
}
};
}
return captureCallback;
}
/**
* Retrieves the JPEG orientation from the specified screen rotation.
*
* @param rotation The screen rotation.
* @return The JPEG orientation (one of 0, 90, 270, and 360)
*/
private int getOrientation(int rotation) {
return (ORIENTATIONS.get(rotation) + cOrientation + 270) % 360;
}
/**
* 处理相机拍照完成的数据
*
* @param reader
*/
Bitmap takeBitmap = null;
Bitmap takeBitmap2 = null;
@SuppressLint("NewApi")
private void onCaptureFinished(ImageReader reader) {
Image image = reader.acquireLatestImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] data = new byte[buffer.remaining()];
buffer.get(data);
image.close();
buffer.clear();
takeBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
/**
* 为了解决预览和拍照左右颠倒问题
*/
Matrix m = new Matrix();
m.postScale(-1, 1); // 镜像水平翻转
takeBitmap2 = Bitmap.createBitmap(takeBitmap,0,0,takeBitmap.getWidth(),takeBitmap.getHeight(),m,true);
if (ioShowBitmapListener != null) {
ioShowBitmapListener.showBitmap(takeBitmap2);
}
// Runtime.getRuntime()
// .gc();
}
@SuppressLint("NewApi")
public void closeCamera() {
if (cSession != null) {
try {
cSession.stopRepeating();
} catch (CameraAccessException e) {
e.printStackTrace();
}
cSession.close();
cSession = null;
}
if (cDevice != null) {
cDevice.close();
cDevice = null;
}
if (cImageReader != null) {
cImageReader.close();
cImageReader = null;
captureRequestBuilder = null;
}
if (cHandlerThread != null) {
cHandlerThread.quitSafely();
try {
cHandlerThread.join();
cHandlerThread = null;
cHandler = null;
} catch (InterruptedException e) {
Log.i(TAG, "--" + e.getMessage());
}
}
if (captureRequestBuilder != null) {
captureRequestBuilder.removeTarget(captureSurface);
captureRequestBuilder = null;
}
if (captureSurface != null) {
captureSurface.release();
captureSurface = null;
}
if (previewRequestBuilder != null) {
previewRequestBuilder.removeTarget(previewSurface);
previewRequestBuilder = null;
}
if (previewSurface != null) {
previewSurface.release();
previewSurface = null;
}
if (takeBitmap!=null){
takeBitmap.recycle();
takeBitmap=null;
}
}
private IOShowBitmapListener ioShowBitmapListener;
public void setIoShowBitmapListener(IOShowBitmapListener ioShowBitmapListener) {
this.ioShowBitmapListener = ioShowBitmapListener;
}
public interface IOShowBitmapListener {
void showBitmap(Bitmap bitmap);
}
}
5. 参考文献
https://blog.csdn.net/wangzhicheng1983/article/details/122660654
6. 下载地址
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