Unable to detect a barcode from an image using Firebase's MLKit

Question

So, i'am trying to scan a barcode with MLKit, but there are no barcodes in the barcode variable in the completion block of self.barcodeDetector?.detect.

The UIImage(named: "barcode.jpg") exists and is loaded correctly (and has barcodes).

So what am I doing wrong/what am I missing?

private var barcodeDetector: VisionBarcodeDetector?
private lazy var vision = Vision.vision()

override func viewDidLoad() {
    super.viewDidLoad()

    guard let barcodeImage = self.imageView.image else { return }

    let format = VisionBarcodeFormat.all
    let barcodeOptions = VisionBarcodeDetectorOptions(formats: format)
    let barcodeDetector = self.vision.barcodeDetector(options: barcodeOptions)

    let imageMetadata = VisionImageMetadata()
    imageMetadata.orientation = UIUtilities.visionImageOrientation(from: barcodeImage.imageOrientation)

    let visionImage = VisionImage(image: barcodeImage)
    visionImage.metadata = imageMetadata

    self.textView.text = ""

    barcodeDetector.detect(in: visionImage) { (barcodes, error) in
    guard error == nil, let barcodes = barcodes, !barcodes.isEmpty else {
        let errorString = error?.localizedDescription ?? "No error description available"
        self.textView.text = "On-Device barcode detection failed with error: \(errorString)"
        return
    }

    self.textView.text = self.textView.text + "\(self.dateFormatter.string(from: Date())) detecting ...\n"
    self.textView.text = self.textView.text + "barcodes.count = \(barcodes.count)" + "\n"
    print(barcodes.count)

    for barcode in barcodes {
        self.textView.text = self.textView.text + "\(barcode)" + "\n"
        print(barcode)
    }
}

So the problem is that the barcodes var is empty so the code in the for loop is not reached...:

        for barcode in barcodes! {
            print(barcode.rawValue!)
        }

P.s. The error variable = nil, so that's not the problem.

image used:

Answer 1

You are most likely missing the "orientation" of the image.

// Define the metadata for the image.
let imageMetadata = VisionImageMetadata()
imageMetadata.orientation = UIUtilities.visionImageOrientation(from: image.imageOrientation)

// Initialize a VisionImage object with the given UIImage.
let visionImage = VisionImage(image: image)
visionImage.metadata = imageMetadata

if that doesn't resolve, try setting the barcode format to "all"

let format = VisionBarcodeFormat.all
let barcodeOptions = VisionBarcodeDetectorOptions(formats: format)
// Create a barcode detector.
let barcodeDetector = vision.barcodeDetector(options: barcodeOptions)

Answer 2

Verify that you have added this line in your pod file:

pod 'Firebase / MLVisionBarcodeModel'