flutter real time face detection

For the real-time access to camera image stream, I answered in another question How to access camera frames in flutter quickly that you want to use CameraController#startImageStream

import 'package:camera/camera.dart';import 'package:flutter/foundation.dart';import 'package:flutter/material.dart';void main() => runApp(MaterialApp(home: _MyHomePage()));class _MyHomePage extends StatefulWidget {  @override  _MyHomePageState createState() => _MyHomePageState();}class _MyHomePageState extends State<_MyHomePage> {  dynamic _scanResults;  CameraController _camera;  bool _isDetecting = false;  CameraLensDirection _direction = CameraLensDirection.back;  @override  void initState() {    super.initState();    _initializeCamera();  }  Future<CameraDescription> _getCamera(CameraLensDirection dir) async {    return await availableCameras().then(      (List<CameraDescription> cameras) => cameras.firstWhere(            (CameraDescription camera) => camera.lensDirection == dir,          ),    );  }  void _initializeCamera() async {    _camera = CameraController(      await _getCamera(_direction),      defaultTargetPlatform == TargetPlatform.iOS          ? ResolutionPreset.low          : ResolutionPreset.medium,    );    await _camera.initialize();    _camera.startImageStream((CameraImage image) {      if (_isDetecting) return;      _isDetecting = true;      try {        // await doOpenCVDectionHere(image)      } catch (e) {        // await handleExepction(e)      } finally {        _isDetecting = false;      }    });  }  Widget build(BuildContext context) {    return null;  }}

I did something this with OpenCV before, my solution was:

1. Start a new Activity or ViewController on Android and iOS respectively via platform channel. Example:

class FaceScanPlugin(val activity: Activity) : MethodCallHandler, PluginRegistry.ActivityResultListener {

var result: Result? = nullcompanion object {    @JvmStatic    fun registerWith(registrar: Registrar): Unit {        val channel = MethodChannel(registrar.messenger(), "com.example.facescan")        val plugin = BarcodeScanPlugin(registrar.activity())        channel.setMethodCallHandler(plugin)        registrar.addActivityResultListener(plugin)    }}override fun onMethodCall(call: MethodCall, result: Result): Unit {    if (call.method.equals("scan")) {        this.result = result        showFaceScanView()    } else {        result.notImplemented()    }}private fun showFaceScanView() {    val intent = Intent(activity, FaceScannerActivity::class.java)    activity.startActivityForResult(intent, 100)}override fun onActivityResult(code: Int, resultCode: Int, data: Intent?): Boolean {    if (code == 100) {        if (resultCode == Activity.RESULT_OK) {            return true        }    }    return false}}

Refer to Flutter QR scanner plugin on how to navigate to Android activity or iOS View.

2. Then do your OpenCV real-time face detection via Camera2 and AVFoundation.

Other than that, I supposed you can try out the new AndroidView or UIKitView if you want to embed the android or iOS into your Flutter app.