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我正在尝试使用 firebase ML kit 独立 API 读取barcode128 和 QR 码。我能够读取条形码和二维码。但如果我的条码长度超过 30-35 个字符，则条码扫描仪无法检测到条码。我能够检测到 QR 码，但不能检测到条形码。

这是我的代码：

// Use this dependency to use the dynamically downloaded model in Google Play Services
implementation 'com.google.android.gms:play-services-mlkit-barcode-scanning:16.1.2'
implementation 'com.google.mlkit:barcode-scanning:16.0.3'

扫描仪活动：

    executor = Executors.newSingleThreadExecutor();
    PreviewView previewView = findViewById(R.id.cameraPreviewView);
    cameraProviderFuture = ProcessCameraProvider.getInstance(this);
    cameraProviderFuture.addListener(() -> {
        try {
            ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
            Preview preview = new Preview.Builder().build();
            CameraSelector cameraSelector = new CameraSelector.Builder()
                    .requireLensFacing(CameraSelector.LENS_FACING_BACK)
                    .build();

            preview.setSurfaceProvider(
                    previewView.createSurfaceProvider());

            ImageCapture imageCapture = new ImageCapture.Builder()
                    .setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
                    .build();

            ImageAnalysis imageAnalysis =
                    new ImageAnalysis.Builder()
                            .build();

            imageAnalysis.setAnalyzer(ContextCompat.getMainExecutor(this), new ImageAnalysis.Analyzer() {

                private BarcodeScanner scanner = buildBarCodeScanner();

                @Override
                public void analyze(ImageProxy imageProxy) {
                    @SuppressLint("UnsafeExperimentalUsageError") Image mediaImage = imageProxy.getImage();
                    if (mediaImage != null) {
                        InputImage image =
                                InputImage.fromMediaImage(mediaImage, imageProxy.getImageInfo().getRotationDegrees());
                        Task<List<Barcode>> result = scanner.process(image);

                        result.addOnSuccessListener(new OnSuccessListener<List<Barcode>>() {
                            @Override
                            public void onSuccess(List<Barcode> barcodes) {
                                processBarCodes(barcodes);
                            }
                        }).addOnFailureListener(new OnFailureListener() {
                            @Override
                            public void onFailure(@NonNull Exception e) {
                                // Task failed with an exception
                                Log.i("CameraXApp3", "scanner task failed. Error:" + e);

                            }
                        }).addOnCompleteListener(new OnCompleteListener<List<Barcode>>() {
                            @Override
                            public void onComplete(@NonNull Task<List<Barcode>> task) {
                                mediaImage.close();
                                imageProxy.close();
                            }
                        });
                    }
                }

                private BarcodeScanner buildBarCodeScanner() {
                    BarcodeScannerOptions options =
                            new BarcodeScannerOptions.Builder()
                                    .setBarcodeFormats(
                                            Barcode.FORMAT_QR_CODE,
                                            Barcode.FORMAT_CODE_128)
                                    .build();
                    return BarcodeScanning.getClient(options);
                }

                private void processBarCodes(List<Barcode> barcodes) {
                    for (Barcode barcode : barcodes) {
                        confirmCounter++;
                        if (confirmCounter >= CONFIRM_VALUE) {
                            confirmCounter = 0;
                            final Rect boundingBox = barcode.getBoundingBox();
                            final Point[] cornerPoints = barcode.getCornerPoints();
                            String rawValue = barcode.getRawValue();
                            int valueType = barcode.getValueType();
                            if (valueType == Barcode.TYPE_TEXT) {
                                toast(MainActivity.this, "Received Message:" + rawValue);
                            }
                        }
                    }
                }

                public void toast(final Context context, final String text) {
                    Handler handler = new Handler(Looper.getMainLooper());
                    handler.post(() -> Toast.makeText(context, text, Toast.LENGTH_LONG).show());
                }
            });

            Camera camera = cameraProvider.bindToLifecycle(
                    ((LifecycleOwner) this),
                    cameraSelector,
                    preview,
                    imageCapture,
                    imageAnalysis);

        } catch (InterruptedException | ExecutionException e) {

        }
    }, ContextCompat.getMainExecutor(this));

我也试图通过点击来增加更多的注意力，但没有运气：

 previewView.setOnTouchListener((v, event) -> {
                v.performClick();
                if (event.getAction() == MotionEvent.ACTION_UP) {
                    final MeteringPointFactory factory = previewView.getMeteringPointFactory();
                    final MeteringPoint point = factory.createPoint(event.getX(), event.getY());
                    final FocusMeteringAction action = new FocusMeteringAction.Builder(point).build();
                    camera.getCameraControl().startFocusAndMetering(action);
                    return false;
                }
                return true;
            });
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1 回答 1

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ML Kit 条码要求最细条的宽度至少为 3 像素。Code-128 每个字符是 11 条宽，因此就像素而言，它是 33 像素宽，对于 35 个这样的字符，它需要 1155 像素的宽度。因此，图像中的条形码至少需要 1155 像素宽。这个粗略的计算忽略了 + + 字符。

您可能需要增加此格式的图像分辨率。

于 2020-09-18T17:48:06.590 回答