在Android上构建人脸检测程序

目录

• 1、导入mlKit依赖包
• 2、配置人脸检测器并且获取人脸检测器
• 3、加载图片资源
• 4、调用人脸检测器
• 5、绘制矩形边框
• 6、完整代码
• 7、效果展示

1、导入mlKit依赖包

dependencies {// ...// Use this dependency to bundle the model with your appimplementation 'com.google.mlkit:face-detection:16.1.5'
}

依赖地址：mlkit

2、配置人脸检测器并且获取人脸检测器

// 1、配置人脸检测器
FaceDetectorOptions faceDetectorOptions = new FaceDetectorOptions.Builder().setPerformanceMode(PERFORMANCE_MODE_FAST).build();
//2、获取人脸检测器
FaceDetector detector = FaceDetection.getClient(faceDetectorOptions);

人脸检测器Api有如下，这里使用了最简单的作为样例：

3、加载图片资源

// 3、从资源中加载图片
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.test3);
imgView.setImageBitmap(bitmap);
InputImage image = InputImage.fromBitmap(bitmap, 0);

这里使用Bitmap，将图片进行转化，然后制作成InputImage流。

4、调用人脸检测器

// 4、处理图片detector.process(image).addOnSuccessListener(new OnSuccessListener<List<Face>>() {@Overridepublic void onSuccess(List<Face> faces) {Log.e("TAG", "onSuccess: " + 1);imgView.setImageBitmap(drawWithRectangle(faces));}}).addOnFailureListener(new OnFailureListener() {@Overridepublic void onFailure(@NonNull Exception e) {Notice();}});

5、绘制矩形边框

private void Notice() {Toast.makeText(this, "识别失败", Toast.LENGTH_SHORT);
}/**** 为人脸绘制边框** @param faces 采集的人脸* @return {@link Bitmap}*/
private Bitmap drawWithRectangle(List<Face> faces) {//复制一个新的BitmapBitmap copiedBitmap = bitmap.copy(bitmap.getConfig(), true);;for (Face face : faces) {//获取边界状态Rect bounds = face.getBoundingBox();// 初始化PaintPaint paint = new Paint();// 设置矩形颜色paint.setColor(Color.BLUE);// 设置绘制样式为轮廓绘制paint.setStyle(Paint.Style.STROKE);// 设置为你需要的宽度paint.setStrokeWidth(10);Canvas canvas = new Canvas(copiedBitmap);canvas.drawRect(bounds, paint);}return copiedBitmap;
}

6、完整代码

import static com.google.mlkit.vision.face.FaceDetectorOptions.PERFORMANCE_MODE_FAST;import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.mlkit.vision.common.InputImage;
import com.google.mlkit.vision.face.Face;
import com.google.mlkit.vision.face.FaceDetection;
import com.google.mlkit.vision.face.FaceDetector;
import com.google.mlkit.vision.face.FaceDetectorOptions;import java.util.List;public class MainActivity extends AppCompatActivity {private ImageView imgView;private Bitmap bitmap;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);imgView = findViewById(R.id.imageView);Button button = findViewById(R.id.button);button.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {// 1、配置人脸检测器FaceDetectorOptions faceDetectorOptions = new FaceDetectorOptions.Builder().setPerformanceMode(PERFORMANCE_MODE_FAST).build();//2、获取人脸检测器FaceDetector detector = FaceDetection.getClient(faceDetectorOptions);// 3、从资源中加载图片bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.test3);imgView.setImageBitmap(bitmap);InputImage image = InputImage.fromBitmap(bitmap, 0);// 4、处理图片detector.process(image).addOnSuccessListener(new OnSuccessListener<List<Face>>() {@Overridepublic void onSuccess(List<Face> faces) {Log.e("TAG", "onSuccess: " + 1);imgView.setImageBitmap(drawWithRectangle(faces));}}).addOnFailureListener(new OnFailureListener() {@Overridepublic void onFailure(@NonNull Exception e) {Notice();}});}});}private void Notice() {Toast.makeText(this, "识别失败", Toast.LENGTH_SHORT);}/**** 为人脸绘制边框** @param faces 采集的人脸* @return {@link Bitmap}*/private Bitmap drawWithRectangle(List<Face> faces) {//复制一个新的BitmapBitmap copiedBitmap = bitmap.copy(bitmap.getConfig(), true);;for (Face face : faces) {//获取边界状态Rect bounds = face.getBoundingBox();// 初始化PaintPaint paint = new Paint();// 设置矩形颜色paint.setColor(Color.BLUE);// 设置绘制样式为轮廓绘制paint.setStyle(Paint.Style.STROKE);// 设置为你需要的宽度paint.setStrokeWidth(10);Canvas canvas = new Canvas(copiedBitmap);canvas.drawRect(bounds, paint);}return copiedBitmap;}}

在相机中识别也是同样的方法，只不过换成相机的视频流。

7、效果展示