使用 CameraX 时，前置摄像头的 Facebase MLKit 人脸检测失败

Posted 2023-03-16

【中文标题】使用 CameraX 时，前置摄像头的 Facebase MLKit 人脸检测失败

【英文标题】：Facebase MLKit face detection failed with front camera when using CameraX

【发布时间】：2020-02-15 16:19:01

【问题描述】：

我正在尝试使用Firebase MLKit 和CameraX ImageAnalysis 实现人脸检测。使用后置摄像头时效果很好，但是当我尝试使用前置摄像头时，它什么也没检测到：

val config = PreviewConfig.Builder()
        .setLensFacing(CameraX.LensFacing.FRONT)
        .build()
val previewUseCase = Preview(config)
previewUseCase.setOnPreviewOutputUpdateListener  previewOutput ->
    viewFinder.post 
        removeView(viewFinder)
        addView(viewFinder, 0)
        viewFinder.surfaceTexture = previewOutput.surfaceTexture
        updateTransform(previewOutput)
    


val highAccuracyOpts = FirebaseVisionFaceDetectorOptions.Builder()
    .setPerformanceMode(FirebaseVisionFaceDetectorOptions.ACCURATE)
    .build()
val detector = FirebaseVision.getInstance().getVisionFaceDetector(highAccuracyOpts)
val imageAnalysisConfig = ImageAnalysisConfig.Builder()
    .setImageReaderMode(ImageAnalysis.ImageReaderMode.ACQUIRE_LATEST_IMAGE)
    .build()
val imageAnalysis = ImageAnalysis(imageAnalysisConfig).apply 
    setAnalyzer(
        Executors.newSingleThreadExecutor(),
        ImageAnalysis.Analyzer  image, rotationDegrees ->
            if (image.image != null && isBusy.compareAndSet(false, true)) 
                val visionImage = FirebaseVisionImage.fromMediaImage(image.image!!, degreesToFirebaseRotation(rotationDegrees))
                detector.detectInImage(visionImage)
                    .addOnSuccessListener  faces ->
                        // faces.size always zero when using front camera
                        Timber.d("$faces.size")
                        isBusy.set(false)
                    
                    .addOnFailureListener  error ->
                        Timber.d("$error")
                    
            
        )


CameraX.bindToLifecycle(lifecycleOwner, previewUseCase, imageAnalysis)

我在装有 android 10 的诺基亚 8.1 上进行了测试。我尝试了https://github.com/firebase/quickstart-android/tree/master/mlkit，它不使用CameraX，它与前置摄像头配合良好。

【参考方案1】：

通过将lensfacing 的ImageAnalysis 设置为CameraX.LensFacing.FRONT 来解决它：

val imageAnalysisConfig = ImageAnalysisConfig.Builder()
    .setLensFacing(CameraX.LensFacing.FRONT)
    .setImageReaderMode(ImageAnalysis.ImageReaderMode.ACQUIRE_LATEST_IMAGE)
    .build()