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feat(example): 实现完整的人脸识别示例

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- 实现注册流程: 人脸检测 -> 活体检测 -> 特征提取(REGISTER) -> 存储
- 实现验证流程: 人脸检测 -> 活体检测 -> 特征提取(RECOGNIZE) -> 比对
- 使用 extractFaceFeature() 和 compareFaceFeature() API
- 使用 SharedPreferences 存储人脸特征数据
- 支持注册/验证模式切换
- 显示相似度和验证结果

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
leon
2026-03-30 16:08:33 +08:00
parent fff221bee2
commit 3c7e992489
2 changed files with 418 additions and 207 deletions
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534
example/lib/main.dart
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@@ -1,10 +1,12 @@
import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:math';
import 'dart:typed_data';
import 'dart:convert';
import 'package:flutter/services.dart';
import 'package:arc/arc.dart';
import 'package:camera/camera.dart';
import 'package:shared_preferences/shared_preferences.dart';
void main() {
runApp(const MyApp());
@@ -123,8 +125,8 @@ class _HomePageState extends State<HomePage> {
final result = await _arcPlugin.init(
detectMode: 0, // 0=VIDEO 模式, 1=IMAGE 模式
orient: 0, // 检测角度优先级
maxFaceNum: 10, // 最大检测人脸数
combinedMask: 0x9D, // 功能组合掩码（人脸检测+识别+年龄+性别+RGB活体）
maxFaceNum: 1, // 单人脸识别场景
combinedMask: 0x9D, // 功能组合掩码
);
if (result != null) {
@@ -146,8 +148,8 @@ class _HomePageState extends State<HomePage> {
}
}
/// 跳转到摄像头预览页面
void _navigateToCameraPreview() async {
/// 跳转到人脸识别页面
void _navigateToFaceRecognition() async {
try {
final cameras = await availableCameras();
if (!mounted) return;
@@ -155,7 +157,7 @@ class _HomePageState extends State<HomePage> {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => CameraPreviewScreen(
builder: (context) => FaceRecognitionScreen(
arcPlugin: _arcPlugin,
cameras: cameras,
),
@@ -253,16 +255,16 @@ class _HomePageState extends State<HomePage> {
),
const SizedBox(height: 24),
// 摄像头预览按钮
// 人脸识别按钮
ElevatedButton(
onPressed: _isInitialized ? _navigateToCameraPreview : null,
onPressed: _isInitialized ? _navigateToFaceRecognition : null,
style: ElevatedButton.styleFrom(
backgroundColor: _isInitialized ? Colors.purple : Colors.grey,
foregroundColor: Colors.white,
padding: const EdgeInsets.symmetric(vertical: 12),
),
child: const Text(
'打开摄像头预览',
'开始人脸识别',
style: TextStyle(fontSize: 16),
),
),
@@ -284,10 +286,11 @@ class _HomePageState extends State<HomePage> {
),
SizedBox(height: 8),
Text(
'1. 请先替换代码中的 _appId、_sdkKey 和 _activeKey 为您的真实密钥\n'
'2. 点击"激活 SDK"按钮进行在线激活\n'
'3. 激活成功后点击"初始化引擎"按钮\n'
'4. 初始化成功后点击"打开摄像头预览"进行人脸检测',
'1. 点击"激活 SDK"按钮进行在线激活\n'
'2. 激活成功后点击"初始化引擎"按钮\n'
'3. 点击"开始人脸识别"进行注册/验证\n\n'
'注册流程: 人脸检测 → 活体检测 → 特征提取 → 存储\n'
'验证流程: 人脸检测 → 活体检测 → 特征提取 → 比对',
style: TextStyle(fontSize: 12),
),
],
@@ -301,42 +304,46 @@ class _HomePageState extends State<HomePage> {
}
}
/// 摄像头预览页面，用于实时人脸检测和 RGB 活体检测
class CameraPreviewScreen extends StatefulWidget {
/// 人脸识别页面 - 实现完整的注册和验证流程
class FaceRecognitionScreen extends StatefulWidget {
final Arc arcPlugin;
final List<CameraDescription> cameras;
const CameraPreviewScreen({
const FaceRecognitionScreen({
super.key,
required this.arcPlugin,
required this.cameras,
});
@override
State<CameraPreviewScreen> createState() => _CameraPreviewScreenState();
State<FaceRecognitionScreen> createState() => _FaceRecognitionScreenState();
}
class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
class _FaceRecognitionScreenState extends State<FaceRecognitionScreen> {
CameraController? _cameraController;
bool _isDetecting = false;
int _faceCount = 0;
String _lastDetectionTime = '';
bool _isProcessing = false;
String _statusMessage = '正在初始化摄像头...';
// RGB 活体检测相关状态
// 检测结果
int _faceCount = 0;
int _rgbLivenessResult = -1; // -1=未检测, 0=非真人, 1=真人
String _rgbLivenessStatus = '未检测';
// 人脸ID管理
/// 存储人脸特征到ID的映射（使用人脸矩形区域的hashCode作为特征标识）
final Map<String, String> _faceIdMap = {};
/// 当前帧检测到的人脸ID列表
List<String> _currentFaceIds = [];
/// 当前帧检测到的人脸特征标识列表（用于注册时关联）
List<String> _currentFaceKeys = [];
/// 随机数生成器
final Random _random = Random();
// 注册的人脸特征数据存储 key
static const String _storedFeatureKey = 'stored_face_feature';
// 当前帧的人脸信息
Map<String, dynamic>? _currentFaceInfo;
Uint8List? _currentNv21Data;
int _currentWidth = 0;
int _currentHeight = 0;
// 模式: 0=注册, 1=验证
int _mode = 0;
String _modeLabel = '注册模式';
// 验证结果
double _similarity = 0.0;
bool _verified = false;
@override
void initState() {
@@ -347,35 +354,22 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
/// 初始化摄像头
Future<void> _initCamera() async {
if (widget.cameras.isEmpty) {
debugPrint('没有可用的摄像头');
setState(() {
_statusMessage = '没有可用的摄像头';
});
return;
}
// 打印所有摄像头信息
debugPrint('========== 摄像头列表 ==========');
for (int i = 0; i < widget.cameras.length; i++) {
final camera = widget.cameras[i];
debugPrint('摄像头 $i:');
debugPrint(' - name: ${camera.name}');
debugPrint(' - lensDirection: ${camera.lensDirection}');
debugPrint(' - sensorOrientation: ${camera.sensorOrientation}');
}
debugPrint('================================');
// 选择后置摄像头作为默认摄像头
// 选择前置摄像头
CameraDescription? selectedCamera;
for (var camera in widget.cameras) {
if (camera.lensDirection == CameraLensDirection.back) {
if (camera.lensDirection == CameraLensDirection.front) {
selectedCamera = camera;
break;
}
}
selectedCamera ??= widget.cameras.first;
debugPrint('选择摄像头: ${selectedCamera.name}');
_cameraController = CameraController(
selectedCamera,
ResolutionPreset.medium,
@@ -385,19 +379,13 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
try {
await _cameraController!.initialize();
debugPrint('摄像头初始化成功');
final size = _cameraController!.value.previewSize;
debugPrint('预览尺寸: ${size?.width}x${size?.height}');
if (mounted) {
setState(() {
_statusMessage = '摄像头: ${selectedCamera?.name ?? "未知"}';
_statusMessage = '摄像头就绪';
});
_startImageStream();
}
} catch (e) {
debugPrint('摄像头初始化失败: $e');
if (mounted) {
setState(() {
_statusMessage = '摄像头初始化失败: $e';
@@ -409,91 +397,66 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
/// 启动图像流
void _startImageStream() {
_cameraController?.startImageStream(_onImageAvailable);
debugPrint('已启动图像流');
}
/// 图像帧回调，进行人脸检测
/// 图像帧回调 - 人脸检测
void _onImageAvailable(CameraImage image) async {
if (_isDetecting) return;
_isDetecting = true;
if (_isProcessing) return;
_isProcessing = true;
try {
final int width = image.width;
final int height = image.height;
// 将图像数据转换为连续的 NV21 格式
final nv21Data = _extractNV21(image, width, height);
// 人脸检测（同时进行 RGB 活体检测）
// 保存当前帧数据用于后续特征提取
_currentNv21Data = nv21Data;
_currentWidth = width;
_currentHeight = height;
// 人脸检测 + RGB 活体检测
final detectResult = await widget.arcPlugin.detectFaces(
data: nv21Data,
width: width,
height: height,
format: 2050, // NV21 格式
format: 2050,
);
if (detectResult != null) {
final success = detectResult['success'] == true;
final faceList = detectResult['faceList'] as List? ?? [];
final rgbLiveness = detectResult['rgbLiveness'] as int? ?? -1;
if (success && faceList.isNotEmpty) {
final now = DateTime.now();
final timeStr = '${now.hour.toString().padLeft(2, '0')}:'
'${now.minute.toString().padLeft(2, '0')}:'
'${now.second.toString().padLeft(2, '0')}.'
'${now.millisecond.toString().padLeft(3, '0')}';
debugPrint('========== 人脸检测 [$timeStr] ==========');
debugPrint('检测到 ${faceList.length} 张人脸');
for (int i = 0; i < faceList.length; i++) {
final face = faceList[i] as Map;
debugPrint('人脸 ${i + 1}: (${face['rectLeft']}, ${face['rectTop']}, ${face['rectRight']}, ${face['rectBottom']})');
}
// 获取 RGB 活体检测结果
final rgbLiveness = detectResult['rgbLiveness'] as int? ?? -1;
final rgbIsAlive = rgbLiveness == 1;
// 保存第一张人脸信息
_currentFaceInfo = Map<String, dynamic>.from(faceList[0] as Map);
if (mounted) {
setState(() {
_faceCount = faceList.length;
_lastDetectionTime = timeStr;
_rgbLivenessResult = rgbLiveness;
_rgbLivenessStatus = rgbIsAlive ? '真人' : (rgbLiveness == 0 ? '非真人' : '未知');
// 更新当前人脸特征标识和ID列表
_currentFaceKeys = faceList.map((face) {
return _getFaceKey(face as Map);
}).toList();
_currentFaceIds = _currentFaceKeys.map((key) {
return _faceIdMap[key] ?? '未注册';
}).toList();
_statusMessage = _rgbLivenessResult == 1 ? '检测到真人' : '检测中...';
});
}
debugPrint('RGB 活体: liveness=$rgbLiveness, isAlive=$rgbIsAlive');
debugPrint('========================================');
} else {
// 未检测到人脸时重置状态
_currentFaceInfo = null;
if (mounted) {
setState(() {
_faceCount = 0;
_rgbLivenessResult = -1;
_rgbLivenessStatus = '未检测';
_currentFaceIds = [];
_currentFaceKeys = [];
_statusMessage = '未检测到人脸';
});
}
}
}
} catch (e, stackTrace) {
} catch (e) {
debugPrint('人脸检测异常: $e');
debugPrint('堆栈: $stackTrace');
} finally {
_isDetecting = false;
_isProcessing = false;
}
}
/// 提取 NV21 数据（处理 stride 对齐）
/// 提取 NV21 数据
Uint8List _extractNV21(CameraImage image, int width, int height) {
final ySize = width * height;
final nv21Size = ySize * 3 ~/ 2;
@@ -550,27 +513,182 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
return nv21;
}
/// 生成随机人脸ID
/// 生成格式: F + 8位随机数字
String _generateRandomFaceId() {
final id = _random.nextInt(100000000).toString().padLeft(8, '0');
return 'F$id';
/// 注册人脸
Future<void> _registerFace() async {
if (_currentFaceInfo == null || _currentNv21Data == null) {
_showMessage('未检测到人脸');
return;
}
if (_rgbLivenessResult != 1) {
_showMessage('请确保是真人');
return;
}
setState(() {
_statusMessage = '正在提取特征...';
});
try {
// 提取特征 (REGISTER 模式)
final result = await widget.arcPlugin.extractFaceFeature(
data: _currentNv21Data!,
width: _currentWidth,
height: _currentHeight,
rectLeft: _currentFaceInfo!['rectLeft'] as int,
rectTop: _currentFaceInfo!['rectTop'] as int,
rectRight: _currentFaceInfo!['rectRight'] as int,
rectBottom: _currentFaceInfo!['rectBottom'] as int,
faceOrientation: _currentFaceInfo!['orient'] as int? ?? 0,
faceId: _currentFaceInfo!['faceId'] as int? ?? -1,
extractType: 0, // REGISTER 模式
mask: 0,
);
if (result != null && result['success'] == true) {
final featureData = result['featureData'] as Uint8List;
// 存储特征数据到本地
final prefs = await SharedPreferences.getInstance();
await prefs.setString(_storedFeatureKey, _bytesToBase64(featureData));
setState(() {
_statusMessage = '注册成功！特征已保存';
});
_showMessage('人脸注册成功！');
} else {
final errorMsg = result?['message'] ?? '未知错误';
setState(() {
_statusMessage = '特征提取失败: $errorMsg';
});
}
} catch (e) {
setState(() {
_statusMessage = '注册异常: $e';
});
}
}
/// 根据人脸矩形区域生成特征标识
String _getFaceKey(Map face) {
// 使用人脸矩形区域的位置和大小作为特征标识
final rectLeft = face['rectLeft'] as int? ?? 0;
final rectTop = face['rectTop'] as int? ?? 0;
final rectRight = face['rectRight'] as int? ?? 0;
final rectBottom = face['rectBottom'] as int? ?? 0;
// 使用位置和大小计算一个简单的特征值（允许一定容差）
final centerX = (rectLeft + rectRight) ~/ 2;
final centerY = (rectTop + rectBottom) ~/ 2;
// 按照区块划分（每50像素为一个区块）
final blockX = centerX ~/ 50;
final blockY = centerY ~/ 50;
return '$blockX-$blockY';
/// 验证人脸
Future<void> _verifyFace() async {
if (_currentFaceInfo == null || _currentNv21Data == null) {
_showMessage('未检测到人脸');
return;
}
if (_rgbLivenessResult != 1) {
_showMessage('请确保是真人');
return;
}
// 读取存储的特征
final prefs = await SharedPreferences.getInstance();
final storedFeatureBase64 = prefs.getString(_storedFeatureKey);
if (storedFeatureBase64 == null) {
_showMessage('请先注册人脸');
return;
}
setState(() {
_statusMessage = '正在提取特征...';
});
try {
// 提取当前帧特征 (RECOGNIZE 模式)
final result = await widget.arcPlugin.extractFaceFeature(
data: _currentNv21Data!,
width: _currentWidth,
height: _currentHeight,
rectLeft: _currentFaceInfo!['rectLeft'] as int,
rectTop: _currentFaceInfo!['rectTop'] as int,
rectRight: _currentFaceInfo!['rectRight'] as int,
rectBottom: _currentFaceInfo!['rectBottom'] as int,
faceOrientation: _currentFaceInfo!['orient'] as int? ?? 0,
faceId: _currentFaceInfo!['faceId'] as int? ?? -1,
extractType: 1, // RECOGNIZE 模式
mask: 0,
);
if (result != null && result['success'] == true) {
final currentFeature = result['featureData'] as Uint8List;
final storedFeature = _base64ToBytes(storedFeatureBase64);
// 比对特征
final compareResult = await widget.arcPlugin.compareFaceFeature(
featureData1: currentFeature,
featureData2: storedFeature,
compareModel: 0, // LIFE_PHOTO 模式
);
if (compareResult != null && compareResult['success'] == true) {
final similarity = compareResult['similarity'] as double? ?? 0.0;
final threshold = 0.8; // 推荐阈值
final isMatch = similarity >= threshold;
setState(() {
_similarity = similarity;
_verified = isMatch;
_statusMessage = isMatch
? '验证通过！相似度: ${(similarity * 100).toStringAsFixed(1)}%'
: '验证失败！相似度: ${(similarity * 100).toStringAsFixed(1)}%';
});
} else {
setState(() {
_statusMessage = '比对失败';
});
}
} else {
setState(() {
_statusMessage = '特征提取失败';
});
}
} catch (e) {
setState(() {
_statusMessage = '验证异常: $e';
});
}
}
/// 切换模式
void _toggleMode() {
setState(() {
_mode = _mode == 0 ? 1 : 0;
_modeLabel = _mode == 0 ? '注册模式' : '验证模式';
_similarity = 0.0;
_verified = false;
});
}
/// 清除注册数据
Future<void> _clearRegistration() async {
final prefs = await SharedPreferences.getInstance();
await prefs.remove(_storedFeatureKey);
setState(() {
_similarity = 0.0;
_verified = false;
_statusMessage = '已清除注册数据';
});
_showMessage('注册数据已清除');
}
/// 字节数组转 Base64
String _bytesToBase64(Uint8List bytes) {
return base64Encode(bytes);
}
/// Base64 转字节数组
Uint8List _base64ToBytes(String base64) {
return base64Decode(base64);
}
/// 显示消息
void _showMessage(String message) {
if (mounted) {
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(content: Text(message)),
);
}
}
@override
@@ -584,9 +702,21 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('人脸检测预览'),
title: Text(_modeLabel),
backgroundColor: Colors.purple,
foregroundColor: Colors.white,
actions: [
IconButton(
icon: const Icon(Icons.swap_horiz),
onPressed: _toggleMode,
tooltip: '切换模式',
),
IconButton(
icon: const Icon(Icons.delete_outline),
onPressed: _clearRegistration,
tooltip: '清除注册数据',
),
],
),
body: Column(
children: [
@@ -595,10 +725,7 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
child: _cameraController != null &&
_cameraController!.value.isInitialized
? Center(
child: RotatedBox(
quarterTurns: -1,
child: CameraPreview(_cameraController!),
),
child: CameraPreview(_cameraController!),
)
: Center(
child: Column(
@@ -612,7 +739,7 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
),
),
// 检测信息显示
// 检测信息和操作面板
Container(
width: double.infinity,
padding: const EdgeInsets.all(16),
@@ -620,26 +747,34 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
// 状态信息
Text(
'检测到人脸数: $_faceCount',
_statusMessage,
style: const TextStyle(
color: Colors.white,
fontSize: 18,
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
const SizedBox(height: 4),
Text(
'最后检测时间: $_lastDetectionTime',
style: const TextStyle(
color: Colors.white70,
fontSize: 14,
),
),
const SizedBox(height: 8),
// RGB 活体检测状态
// 人脸和活体状态
Row(
children: [
Icon(
_faceCount > 0 ? Icons.face : Icons.face_retouching_off,
color: _faceCount > 0 ? Colors.green : Colors.grey,
size: 20,
),
const SizedBox(width: 8),
Text(
'人脸: ${_faceCount > 0 ? "已检测" : "未检测"}',
style: TextStyle(
color: _faceCount > 0 ? Colors.green : Colors.grey,
fontSize: 14,
),
),
const SizedBox(width: 16),
Icon(
_rgbLivenessResult == 1
? Icons.check_circle
@@ -655,98 +790,83 @@ class _CameraPreviewScreenState extends State<CameraPreviewScreen> {
),
const SizedBox(width: 8),
Text(
'RGB活体: $_rgbLivenessStatus',
'活体: ${_rgbLivenessResult == 1 ? "真人" : _rgbLivenessResult == 0 ? "非真人" : "未知"}',
style: TextStyle(
color: _rgbLivenessResult == 1
? Colors.green
: _rgbLivenessResult == 0
? Colors.red
: Colors.white70,
: Colors.orange,
fontSize: 14,
),
),
],
),
// 人脸ID显示
if (_currentFaceIds.isNotEmpty) ...[
// 验证结果显示
if (_mode == 1 && _similarity > 0) ...[
const SizedBox(height: 8),
const Divider(color: Colors.white24),
const SizedBox(height: 8),
Text(
'人脸ID:',
style: const TextStyle(
color: Colors.white,
fontSize: 14,
fontWeight: FontWeight.bold,
),
),
const SizedBox(height: 4),
Wrap(
spacing: 8,
runSpacing: 4,
children: _currentFaceIds.asMap().entries.map((entry) {
final index = entry.key;
final id = entry.value;
final isRegistered = id != '未注册';
return Container(
padding: const EdgeInsets.symmetric(
horizontal: 8,
vertical: 4,
Row(
children: [
Icon(
_verified ? Icons.verified_user : Icons.warning,
color: _verified ? Colors.green : Colors.red,
size: 24,
),
const SizedBox(width: 8),
Text(
'相似度: ${(_similarity * 100).toStringAsFixed(1)}%',
style: TextStyle(
color: _verified ? Colors.green : Colors.red,
fontSize: 18,
fontWeight: FontWeight.bold,
),
decoration: BoxDecoration(
color: isRegistered ? Colors.green.withValues(alpha: 0.3) : Colors.orange.withValues(alpha: 0.3),
borderRadius: BorderRadius.circular(4),
border: Border.all(
color: isRegistered ? Colors.green : Colors.orange,
),
),
const SizedBox(width: 8),
Text(
_verified ? '验证通过' : '非本人',
style: TextStyle(
color: _verified ? Colors.green : Colors.red,
fontSize: 14,
),
child: Text(
'人脸${index + 1}: $id',
style: TextStyle(
color: isRegistered ? Colors.greenAccent : Colors.orangeAccent,
fontSize: 12,
),
),
);
}).toList(),
),
],
),
],
// 注册按钮
if (_faceCount > 0) ...[
const SizedBox(height: 12),
SizedBox(
width: double.infinity,
child: ElevatedButton.icon(
onPressed: () {
// 为未注册的人脸生成随机ID，并存入映射表
setState(() {
for (int i = 0; i < _faceCount; i++) {
if (_currentFaceIds[i] == '未注册') {
final newId = _generateRandomFaceId();
final faceKey = _currentFaceKeys[i];
// 将特征标识和ID存入映射表
_faceIdMap[faceKey] = newId;
_currentFaceIds[i] = newId;
}
}
});
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(
content: Text('人脸ID已生成！'),
backgroundColor: Colors.green,
),
);
},
icon: const Icon(Icons.person_add),
label: const Text('注册人脸（生成随机ID）'),
style: ElevatedButton.styleFrom(
backgroundColor: Colors.blue,
foregroundColor: Colors.white,
padding: const EdgeInsets.symmetric(vertical: 12),
const SizedBox(height: 12),
// 操作按钮
Row(
children: [
Expanded(
child: ElevatedButton.icon(
onPressed: _mode == 0 ? _registerFace : _verifyFace,
icon: Icon(_mode == 0 ? Icons.person_add : Icons.verified_user),
label: Text(_mode == 0 ? '注册人脸' : '验证身份'),
style: ElevatedButton.styleFrom(
backgroundColor: _mode == 0 ? Colors.blue : Colors.green,
foregroundColor: Colors.white,
padding: const EdgeInsets.symmetric(vertical: 12),
),
),
),
],
),
// 提示
const SizedBox(height: 8),
Text(
_mode == 0
? '提示: 注册时会提取人脸特征并保存到本地'
: '提示: 验证时会与已注册的特征进行比对，阈值 0.8',
style: const TextStyle(
color: Colors.white54,
fontSize: 11,
),
],
),
],
),
),