使用Flutter和Firebase_ml_vision无法使人脸检测正常工作

如何解决使用Flutter和Firebase_ml_vision无法使人脸检测正常工作

我已经为此苦苦挣扎了大约24个小时，而关于如何解决这个问题的想法已经结束。

我编写了从Firebase加载图像并在其中检测到人脸的代码-完全没有问题。但是，当我随后尝试使用Flutter中的标准imagePicker类拍照时，尽管我实际上在屏幕上显示了图像以检查其是否为有效文件，但是faceDetector却无法在图片。

下面是该代码的编辑后版本。由于我的项目中缺少某些内容，因此不会进行编译，但希望您能理解。测试平台是iOS（设备，而不是模拟器）。插件为firebase_ml_vision 0.9.6 + 2，而flutter的版本是几天前的最新版本。

有人有什么想法吗？

import 'package:flutter/material.dart';
import 'package:firebase_ml_vision/firebase_ml_vision.dart';
import 'package:image_picker/image_picker.dart';
import 'package:modal_progress_hud/modal_progress_hud.dart';
import 'dart:io';
import 'dart:async';
import 'package:camera/camera.dart';

class imageComparison extends StatefulWidget {
  @override
  _imageComparison createState() => _imageComparison();
}

class _imageComparison extends State<imageComparison> {
  CameraController controller;
  List<CameraDescription> cameras;
  File chosenImage;
  bool gotImage = false;
  File grabbedImage;
  FaceDetector faceDetector;
  File tempImg;

  @override
  void initState() {
    super.initState();

    faceDetector = FirebaseVision.instance.faceDetector(FaceDetectorOptions(enableLandmarks: true,enableContours: true,enableClassification: true));

    availableCameras().then((value) {
      cameras = value;
      controller = CameraController(cameras[1],ResolutionPreset.medium);
      controller.initialize().then((_) {
        if (!mounted) {
          return;
        }
        setState(() {});
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    if (controller == null) {
      return Scaffold(
        backgroundColor: Colors.white,body: Container(),);
    }

    if (!gotImage) {
      File img;
      downloadImage(imageURLs[0],'verificationImage.jpg').then((value) {
        img = tempImg = value;
        extractFace(img).then((value2) {
          print('got image');
          gotImage = true;
          setState(() {});
        });
      });
    }

    return Scaffold(
      backgroundColor: Colors.white,body: ModalProgressHUD(
        inAsyncCall: globals.showSpinner,child: Container(
          width: globals.SizeConfig.blockSizeHorizontal * 100,height: globals.SizeConfig.blockSizeVertical * 100,decoration: BoxDecoration(
            gradient: gradient,),child: Stack(
            children: <Widget>[
              Positioned(
                left: globals.SizeConfig.blockSizeHorizontal * 10,top: globals.SizeConfig.blockSizeVertical * 5,child: Column(
                  children: [
                    FlatButton(
                      child: Text(
                        'check',textAlign: TextAlign.center,style: TextStyle(color: Colors.white,fontSize: globals.SizeConfig.blockSizeHorizontal * 4),color: Colors.red,onPressed: () async {
                        bool res = await takeAndAnalyseImage();
                        //other stuff
                      },],);
  }

  Future<bool> takeAndAnalyseImage() async {
    //String filepath = await takePicture();

    grabbedImage = File((await ImagePicker().getImage(source: ImageSource.camera)).path);

    //grabbedImage = File(filepath);
    setState(() {
      print('setting state');
    });
    while (grabbedImage == null) {}

    if (mounted) {
      extractFace(grabbedImage).then((value) {
        //irrelevant stuff
      });
    }
    return null;
  }

  Future<Map<String,dynamic>> extractFace(File img) async {
    FirebaseVisionImage visionImage;

    visionImage = FirebaseVisionImage.fromFile(img);

    Map<String,dynamic> facevals = Map<String,dynamic>();
    List<Face> faces;
    try {
      faces = await faceDetector.processImage(visionImage);
    } catch (e) {
      print('can\'t extract face from image. e = ' + e.toString());
    }
    for (Face face in faces) {
      //do irrelevant stuff to question.
    }
    return facevals;
  }
}

编辑：将图像转换为'FirebaseVisionImage'似乎效果很好-是FaceDetector.processImage失败了...