android29人脸识别

Android 29 人脸识别

什么是人脸识别？

人脸识别是一种生物特征识别技术，通过分析人脸图像或视频流中的特征来识别和验证个人的身份。这项技术已经广泛应用于安全领域、人机交互以及数字娱乐等领域。

Android 29 人脸识别新特性

Android 29 版本引入了新的人脸识别 API，使开发人员能够更方便地在应用中集成人脸识别功能。下面我们将介绍如何在 Android 29 中使用人脸识别 API。

步骤一：添加权限和依赖

在 AndroidManifest.xml 文件中添加以下权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.INTERNET" />

在 build.gradle 文件中添加以下依赖：

implementation 'androidx.camera:camera-camera2:1.0.0-beta01'
implementation 'androidx.camera:camera-lifecycle:1.0.0-beta01'
implementation 'org.tensorflow:tensorflow-lite:2.3.0'
implementation 'org.tensorflow:tensorflow-lite-gpu:2.3.0'

步骤二：创建人脸检测器

在你的项目中创建一个人脸检测器类，用于检测图像中的人脸。以下是一个简单的示例：

import android.graphics.Bitmap;
import android.media.Image;
import android.os.Bundle;

import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageProxy;

import com.google.android.gms.tasks.Task;
import com.google.android.gms.tasks.TaskCompletionSource;

import java.nio.ByteBuffer;

public class FaceDetector implements ImageAnalysis.Analyzer {

    private static final int IMAGE_MEAN = 128;
    private static final float IMAGE_STD = 128.0f;

    private final TaskCompletionSource<Bitmap> bitmapTaskCompletionSource = new TaskCompletionSource<>();

    public Task<Bitmap> getBitmapTask() {
        return bitmapTaskCompletionSource.getTask();
    }

    @Override
    public void analyze(ImageProxy imageProxy) {
        Image image = imageProxy.getImage();
        if (image != null) {
            ByteBuffer buffer = image.getPlanes()[0].getBuffer();
            byte[] bytes = new byte[buffer.remaining()];
            buffer.get(bytes);

            int width = image.getWidth();
            int height = image.getHeight();

            Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
            bitmap.copyPixelsFromBuffer(ByteBuffer.wrap(bytes));

            bitmapTaskCompletionSource.setResult(bitmap);

            image.close();
            imageProxy.close();
        }
    }
}

步骤三：在 Activity 中使用人脸识别功能

在你的 Activity 中使用 CameraX API 来启动相机预览，并将预览的图像传递给人脸检测器进行人脸识别。以下是一个简单的示例：

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.Camera;
import androidx.camera.core.CameraSelector;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageCapture;
import androidx.camera.core.ImageCaptureException;
import androidx.camera.lifecycle.ProcessCameraProvider;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import com.google.common.util.concurrent.ListenableFuture;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_CAMERA_PERMISSION = 100;

    private ImageView previewImageView;
    private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        previewImageView = findViewById(R.id.preview_image_view);

        cameraProviderFuture = ProcessCameraProvider.getInstance(this);
        cameraProviderFuture.addListener(() -> {
            try {
                ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
                bindCameraPreview(cameraProvider);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }, ContextCompat.getMainExecutor(this));
    }

    private void bindCameraPreview(ProcessCameraProvider cameraProvider) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.CAMERA},
                    REQUEST_CAMERA_PERMISSION);
            return;
        }

        CameraSelector cameraSelector = new CameraSelector.Builder()
                .requireLensFacing(CameraSelector.LENS_FACING_FRONT)
                .build();

        ImageAnalysis imageAnalysis = new ImageAnalysis.Builder()
                .setBackpressure