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import UIKit
import Vision
import VisionKit
class ViewController: UIViewController, VNDocumentCameraViewControllerDelegate {
@IBOutlet weak var imageView: UIImageView!
@IBOutlet weak var textView: UITextView!
var textRecognitionRequest = VNRecognizeTextRequest(completionHandler: nil)
private let textRecognitionWorkQueue = DispatchQueue(label: "MyVisionScannerQueue", qos: .userInitiated, attributes: [], autoreleaseFrequency: .workItem)
override func viewDidLoad() {
super.viewDidLoad()
textView.isEditable = false
setupVision()
}
@IBAction func btnTakePicture(_ sender: Any) {
let scannerViewController = VNDocumentCameraViewController()
scannerViewController.delegate = self
present(scannerViewController, animated: true)
}
private func setupVision() {
textRecognitionRequest = VNRecognizeTextRequest { (request, error) in
guard let observations = request.results as? [VNRecognizedTextObservation] else { return }
var detectedText = ""
for observation in observations {
guard let topCandidate = observation.topCandidates(1).first else { return }
print("text \(topCandidate.string) has confidence \(topCandidate.confidence)")
detectedText += topCandidate.string
detectedText += "\n"
}
DispatchQueue.main.async {
self.textView.text = detectedText
self.textView.flashScrollIndicators()
}
}
textRecognitionRequest.recognitionLevel = .accurate
}
private func processImage(_ image: UIImage) {
imageView.image = image
recognizeTextInImage(image)
}
private func recognizeTextInImage(_ image: UIImage) {
guard let cgImage = image.cgImage else { return }
textView.text = ""
textRecognitionWorkQueue.async {
let requestHandler = VNImageRequestHandler(cgImage: cgImage, options: [:])
do {
try requestHandler.perform([self.textRecognitionRequest])
} catch {
print(error)
}
}
}
func documentCameraViewController(_ controller: VNDocumentCameraViewController, didFinishWith scan: VNDocumentCameraScan) {
guard scan.pageCount >= 1 else {
controller.dismiss(animated: true)
return
}
let originalImage = scan.imageOfPage(at: 0)
let newImage = compressedImage(originalImage)
controller.dismiss(animated: true)
processImage(newImage)
}
func documentCameraViewController(_ controller: VNDocumentCameraViewController, didFailWithError error: Error) {
print(error)
controller.dismiss(animated: true)
}
func documentCameraViewControllerDidCancel(_ controller: VNDocumentCameraViewController) {
controller.dismiss(animated: true)
}
func compressedImage(_ originalImage: UIImage) -> UIImage {
guard let imageData = originalImage.jpegData(compressionQuality: 1),
let reloadedImage = UIImage(data: imageData) else {
return originalImage
}
return reloadedImage
}
}
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