我目前正在开发需要实时面部检测的应用程序。现在,我在应用程序中拥有mlkit库,并且正在使用Firebase人脸检测器。此刻,每次我尝试从文件中检测到人脸时,它都会产生错误:
DynamiteModule(13840): Local module descriptor class for com.google.android.gms.vision.dynamite.face not found.
对于实时部分,我尝试在颤振中使用RepaintBoundary来获取(几乎)每帧相机小部件的屏幕快照,并将其转换为用于面部检测的二进制文件。但是由于某种原因,每次我尝试对相机小部件进行屏幕截图时,抖动都会崩溃。它适用于其他小部件。
在遇到这两个问题并花了相当长的时间试图解决它们之后,我一直在考虑只使用android / iOS本机代码来做应用程序的摄像头部分(我会使用OpenCV来做到这一点,所以我可以进行实时检测)。有没有一种方法可以使用平台通道在Kotlin中实现相机视图并将其快速导入并导入到flutter小部件中?还是有另一种更简单的方法来实现这一点?
答案 0 :(得分:2)
要实时访问摄像机图像流,我在另一个问题How to access camera frames in flutter quickly中回答了您要使用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;
}
}
答案 1 :(得分:0)
我以前用OpenCV做过这样的事情,我的解决方法是:
class FaceScanPlugin(val activity: Activity) : MethodCallHandler, PluginRegistry.ActivityResultListener {
var result: Result? = null
companion 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
}
}
有关如何导航到Android活动或iOS视图的信息,请参见Flutter QR scanner plugin。
除此之外,我想如果要将android或iOS嵌入Flutter应用中,可以尝试使用新的AndroidView或UIKitView。