UPDATE: I've made a fully open source project that may help you do exactly what you need. Check it out: https://github.com/ethanwa/credit-card-scanner-and-validator
**
You can't do much to improve accuracy beyond adding some preset values to specifically look for, which doesn't make sense with CC numbers so I won't even bother showing that code. You'll need to rely on Apple to improve their text recognition model as iOS iterates for it to truly improve.
What I suggest in the meantime are these two things you can do:
Do validation on your credit card numbers that you think you're recieving. For example, Visa starts with 4, MasterCard starts with 5, Discover with 6, Amex with 3, etc. They have specific lengths and so on. See here: https://www.freeformatter.com/credit-card-number-generator-validator.html
Keep iterating over and over on a camera feed until you get a number that validates. I'm not sure if you are currently just taking a picture of the card, and processing that image (which it sounds like you are doing), but you should be processing many images per second until you get a valid CC. This is most likely how Apple does it when adding a card via Apple Pay on your phone, or when depositing checks digitally using banking apps (finding valid routing and account numbers).
Here's an example of what I mean...
I wrote this code that can pick out and validate ISBN numbers (basically 10 and 13 digit numbers that catalog books, which have a check digit for validation) in any given text and will keep looking until it finds all the numbers and then validates. It works extremely well and is very fast. Check out this Swift 5.3 code:
import UIKit
import Vision
import Photos
import AVFoundation
class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
var recognizedText = ""
var finalText = ""
var image: UIImage?
var processing = false
@IBOutlet weak var nameLabel: UILabel!
@IBOutlet weak var setLabel: UILabel!
@IBOutlet weak var numberLabel: UILabel!
lazy var textDetectionRequest: VNRecognizeTextRequest = {
let request = VNRecognizeTextRequest(completionHandler: self.handleDetectedText)
request.recognitionLevel = .accurate
request.usesLanguageCorrection = false
return request
}()
private let videoOutput = AVCaptureVideoDataOutput()
private let captureSession = AVCaptureSession()
private lazy var previewLayer: AVCaptureVideoPreviewLayer = {
let preview = AVCaptureVideoPreviewLayer(session: self.captureSession)
preview.videoGravity = .resizeAspect
return preview
}()
// MARK: AV
override func viewDidLoad() {
super.viewDidLoad()
self.addCameraInput()
self.addVideoOutput()
}
private func addCameraInput() {
let device = AVCaptureDevice.default(for: .video)!
let cameraInput = try! AVCaptureDeviceInput(device: device)
self.captureSession.addInput(cameraInput)
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
self.previewLayer.frame = self.view.bounds
}
private func addVideoOutput() {
self.videoOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString) : NSNumber(value: kCVPixelFormatType_32BGRA)] as [String : Any]
self.videoOutput.setSampleBufferDelegate(self, queue: DispatchQueue(label: "my.image.handling.queue"))
self.captureSession.addOutput(self.videoOutput)
}
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection)
{
if !processing
{
guard let frame = CMSampleBufferGetImageBuffer(sampleBuffer) else {
debugPrint("unable to get image from sample buffer")
return
}
print("did receive image frame")
// process image here
self.processing = true
let ciimage : CIImage = CIImage(cvPixelBuffer: frame)
let theimage : UIImage = self.convert(cmage: ciimage)
self.image = theimage
processImage()
}
}
// Convert CIImage to CGImage
func convert(cmage:CIImage) -> UIImage
{
let context:CIContext = CIContext.init(options: nil)
let cgImage:CGImage = context.createCGImage(cmage, from: cmage.extent)!
let image:UIImage = UIImage.init(cgImage: cgImage)
return image
}
// AV
func processImage()
{
DispatchQueue.main.async {
self.nameLabel.text = ""
self.setLabel.text = ""
self.numberLabel.text = ""
}
guard let image = image, let cgImage = image.cgImage else { return }
let requests = [textDetectionRequest]
let imageRequestHandler = VNImageRequestHandler(cgImage: cgImage, orientation: .right, options: [:])
DispatchQueue.global(qos: .userInitiated).async {
do {
try imageRequestHandler.perform(requests)
} catch let error {
print("Error: \(error)")
}
}
}
fileprivate func handleDetectedText(request: VNRequest?, error: Error?)
{
self.finalText = ""
if let error = error {
print(error.localizedDescription)
self.processing = false
return
}
guard let results = request?.results, results.count > 0 else {
print("No text was found.")
self.processing = false
return
}
if let requestResults = request?.results as? [VNRecognizedTextObservation] {
self.recognizedText = ""
for observation in requestResults {
guard let candidiate = observation.topCandidates(1).first else { return }
self.recognizedText += candidiate.string
self.recognizedText += " "
}
var replaced = self.recognizedText.replacingOccurrences(of: "-", with: "")
replaced = String(replaced.filter { !"\n\t\r".contains($0) })
let replacedArr = replaced.components(separatedBy: " ")
for here in replacedArr
{
let final = here.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
if (final.count == 10 || final.count == 13) && final.containsISBNnums && Validate.isbn(final) // validate barcode
{
self.finalText += final
print(final)
self.captureSession.stopRunning()
DispatchQueue.main.async {
self.previewLayer.removeFromSuperlayer()
}
break
}
}
DispatchQueue.main.async {
self.numberLabel.text = self.finalText
}
}
self.processing = false
}
// MARK: Buttons
// This is a live camera view that will start a capture session
@IBAction func takePhoto(_ sender: Any) {
self.view.layer.addSublayer(self.previewLayer)
self.captureSession.startRunning()
}
@IBAction func choosePhoto(_ sender: Any) {
presentPhotoPicker(type: .photoLibrary)
}
fileprivate func presentPhotoPicker(type: UIImagePickerController.SourceType) {
let controller = UIImagePickerController()
controller.sourceType = type
controller.delegate = self
present(controller, animated: true, completion: nil)
}
}
extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
dismiss(animated: true, completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
dismiss(animated: true, completion: nil)
image = info[.originalImage] as? UIImage
processImage()
}
}
extension String {
var containsISBNnums: Bool {
guard self.count > 0 else { return false }
let nums: Set<Character> = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "X"]
return Set(self).isSubset(of: nums)
}
}
